Perkutane Entfernung eines intraperitonealen Fremdkörpers

MR-Angiographie peripherer Gefäße mit automatischer Verschiebetisch-Technik bei 1.0 T im Vergleich zur i. a. DSA

PURPOSE Contrast-enhanced (CE) 3D-MR angiography of peripheral arteries was performed in 8 patients with peripheral arterial occlusive disease by applying a new tracking technique on a 1.0 T system (Magnetom Harmony, Siemens). The studies were compared with intra-arterial digital angiography as gold standard. MATERIALS AND METHODS Imaging of the distal aorta, pelvis, upper and lower limb arteries was accomplished with a Flash-3D-sequence (TR/TE = 6.2/3.2 ms) within 26 s acquisition time of each region after a single bolus of 30 ml contrast agent. Individual circulation time was determined by a test bolus before each examination. RESULTS 112 vessel segments were evaluated. MR angiography ach…

Dynamic MR imaging of breast lesions: correlation with microvessel distribution pattern and histologic characteristics of prognosis.

To evaluate the association of dynamic enhancement parameters of benign and malignant breast lesions at magnetic resonance (MR) imaging with microvessel distribution and histologic prognostic tumor characteristics.Regional review board approval and informed consent were obtained. Surgical resection specimens of breast lesions (32 benign, 86 malignant) in 118 patients (age range, 28-86 years; mean, 58 years) who had undergone dynamic T1-weighted MR imaging of both breasts were included in the study. Different MR enhancement parameters and microvessel density (MVD) distribution were determined. In malignant lesions, TNM stage, tumor grade, proliferative activity, and hormone receptor expressi…

Hydro-MRT mit schnellen Sequenzen bei Morbus Crohn: Vergleich mit der fraktionierten Magen-Darm-Passage

PURPOSE To compare the value of hydro-MRI with that of barium studies in patients with Crohn's disease. MATERIALS AND METHODS After an oral bowel opacification using 1000 ml of a 2.5% mannitol solution, axial and coronal breath-hold sequences (T2W HASTE +/- FS, contrast-enhanced T1W FLASH FS) were acquired in 46 patients with Crohn's disease at 1.0 T. The findings of hydro-MRI were compared with those of barium studies. RESULTS In the stomach and the small bowel, hydro-MRI and barium studies demonstrated similar numbers of Crohn's involvements (39 vs. 36); in the colon, hydro-MRI showed clearly more affections (23 vs. 10). Hydro-MRI showed 12.7 cm of inflamed bowel per patient, on average (…

Flußquantifizierung von intrakardialen Shuntvolumina unter Verwendung der MR-Phasenkontrast-Technik in Atemanhaltephase

PURPOSE Comparison of a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence for intracardiac shunt flow measurement with the invasive shunt size determination by oximetry. PATIENTS AND METHODS 10 patients with different cardiac shunts (6 ASD/3 VSD/1 PDA) and four healthy individuals were investigated using a 1.5 Tesla Siemens Vision system. For flow measurements a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence was used ('through plane', FLASH 2D-sequence, TR/TE 110/5 ms, 'velocity encoding' 250 cm/s). Mean flow (ml/R-R interval) in the ascending aorta, the pulmonary trunk, and the right and left pulmonary arteries was determined…

Was heißt wie? Ansatz und Glossar zu Befundung und Verständnis in der HRCT der Lunge

In HRCT reports multiple different, often synonymous, German and English terms are used. The variety of terms impede understanding and acceptance of HRCT. Purpose of this paper is to present a scheme, which is based on the anatomic landmarks (secondary lobule), and the density of pathologic changes, as well as a glossary from the German HRCT-literature, including suitable terms, definitions, synonyms and English terms. Low attenuation changes include emphysemas, air-filled cavities (bullae, cysts, cavitations, honeycombing) and bronchial dilatation, changes with increased density consist of diffuse (ground glass opacity, consolidation) and focal processes (reticular and nodular densities). …

Multirotations-CT und ARDS

Purpose Aim of the study was to investigate alveolar inspiration and expiration using multiscan CT. Results of a visual assessment using a scoring system were compared with density ranges known to represent alveolar ventilation best. Method Pigs were examined before and after lavage-induced ARDS. All animals were examined using dynamic multiscan CT. The visual assessment was done by a scoring system proposed by Gattinoni. The results were compared with planimetric determination of defined density ranges. Results In the healthy lung, the visual analysis showed higher scores at lower airway pressures with a marked gradient, whereas at higher pressures neither opacities nor gradients were obse…

Digitale Mehrschichttomographie

A set of projection images is acquired during longitudinal tomography with an image intensifier TV system. Reconstruction of tomograms in each desired plane is achieved by shifting and summing up of the digitalized projection images. Digital multilayer and conventional film tomograms mainly of the respiratory tract and skeleton have been compared in 100 patients. Image quality is comparable with both methods. Disadvantage of digital tomography is lower spatial resolution (512 x 512 matrix size); advantages include lower radiation dose, shorter study time, and facilities of digital imaging.

Bone age determination based on the study of the medial extremity of the clavicle

The development of the medial clavicular epiphysis and its fusion with the clavicular shaft have been a subject of medical research since the second decade of this century. Computed tomography provides the imaging modality of choice in analyzing the maturation process of the sternal end of the clavicle. In a retrospective study, we analyzed normal development in 380 individuals under the age of 30 years. The appearance of an epiphyseal ossification center occurred between ages 11 and 22 years. Partial union was found from age 16 until age 26 years. Complete union was first noted at age 22 years and in 100 % of the sample at age 27 years. Based on these data, age-related standardized age dis…

Gegenüberstellung der Wertigkeit von Angioskopie, Angiographie und Sonographie zur Erfassung pathologischer Gefäßwandprozesse

AIMS The ability of angioscopy, angiography and sonography to evaluate arteriosclerotic vascular lesions were compared to determine if angioscopy is a valuable addition in the diagnostic armamentarium. METHODS An in-vitro study was selected to enable microscopic assessment of the arteries. Angiography was followed by sonography and endoscopy and finally the vessels were evaluated macro- and microscopically. RESULTS The configuration of the vascular stenosis (plaque-shape, semicircular-eccentric, circular-concentric) was more reliably defined with angioscopy as compared to angiography and sonography. Intense calcification of plaque was detected sonographically with a high sensitivity (90%) u…

Retrograde Venenokklusion - Zur Therapie der verlogenen Impotenz

Retrograde occlusion of penile drainage veins can produce improvement in patients with impotence due to venous leaks. We performed 50 transfemoral and three transjugular procedures; 46 (86%) were technically successful. Clinical improvement was found in 24 out of the 46 procedures (52%). In 20 patients spontaneous intercourse became possible, in four this occurred after intracavernous injection of vaso-active substances. In eleven patients there was deterioration after one to twenty months; in seven this was treated by repeated venous occlusion. In 13 patients improvement has been maintained over a period of one to thirty months (average 10.5 months). There were no complications.

Assessment of left ventricular function by breath-hold cine MR imaging: Comparison of different steady-state free precession sequences

Purpose To compare steady-state free precession (SSFP) sequence protocols with different acquisition times (TA) and temporal resolutions (tRes) due to the implementation of a view sharing technique called shared phases for the assessment of left ventricular (LV) function by breath-hold cine magnetic resonance (MR) imaging. Materials and Methods End-diastolic and end-systolic volumes (EDV, ESV) were measured in contiguous short-axis slices with a thickness of 8 mm acquired in 10 healthy male volunteers. The following true fast imaging with steady-state precession (TrueFISP) sequence protocols were compared: protocol A) internal standard of reference, segmented: tRes 34.5 msec, TA 18 beats pe…

MR-Perfusionsbildgebung des Herzens mit TrueFISP

OBJECTIVE Development and test of a saturation-recovery TrueFISP (SR-Trufi) pulse sequence for myocardial perfusion MR imaging (MRI) using improved gradient hardware. MATERIAL AND METHODS Measurements were performed on a 1.5 T scanner with prototype gradients (50 mT/m, minimum rise time 300 microseconds). T1-weighted first-pass MRI of Gd-DTPA (0.025 mumol/kg) kinetics in the myocardium was performed using an SR-Trufi pulse sequence (TR/TE/alpha = 2.6 ms/1.4 ms/55 degrees) with a saturation preparation of TD = 30 ms before the TrueFISP readout. Measurements were performed in volunteers (n = 4) and in a pig model of chronic ischemia (n = 1). RESULTS In phantoms, the signal intensity was linea…

Controlling diffusion of 3He by buffer gases: a structural contrast agent in lung MRI.

Purpose: To study the influence of admixing inert buffer gases to laser-polarized 3 He in terms of resulting diffusion coefficients and the consequences for image contrast and resolution. Materials and Methods: The diffusion coefficient of 3 He was altered by admixing buffer gases of various molecular weights ( 4 He, N2, and SF6). The influence of the pulse sequence and the diffusion coefficient on the appearance of MRI of (laserpolarized) gases was analyzed by comparison of basic theoretical concepts with demonstrative experiments. Results: Excellent agreement between theoretical description and observed signal in simple gradient echoes was observed. A maximum signal gain can be predicted …

Erfahrungen mit einer 3D-Navigatorsequenz zur Koronargefäßdarstellung an einem Hochleistungs-MR-System

Purpose: To evaluate MR coronary angiography using a three-dimensional navigator echo sequence on a MR scanner with a high performance gradient system. Material and Methods: Five healthy volunteers were examined with a 1.5 Tesla MR system, using a high performance prototype gradient system (peak amplitude 50 mT/m, rising time 600 μs). For imaging, a navigated gradient-echo pulse sequence with an in-plane resolution between 0.63 × 0.63 and 0.78 × 0.78 mm 2 was used. Per patient two overlapping slabs were acquired. The number of visualised coronary artery segments was estimated (AHA classification). In addition, signal-to-noise measurements were performed in the ascending aorta at the level o…

Transrenal ureteral occlusion: results and problems.

Purpose The effectiveness of transrenal ureteral occlusion was evaluated. Patients and Methods Transrenal ureteral occlusions were performed in 83 ureters of 76 patients. Thirty-one ureters were occluded with use of tissue adhesive, which was secured in place with Gianturco coils in 21. Fifty-two ureters were occluded by means of silicone-filled, detachable latex balloons. Average follow-up was 3.6 months (range, 1 week to 38 months) for patients treated with the tissue adhesive and 7.9 months (range, 1 week to 61 months) for patients treated with the detachable balloons. Results Seventeen (55%) of the 31 ureters occluded with tissue adhesive and 36 (69%) of the 52 ureters occluded with det…

Quantification of Regional Intrapulmonary Oxygen Partial Pressure Evolution during Apnea by 3He MRI

We present a new method to determine in vivo the temporal evolution of intrapulmonary oxygen concentrations by functional lung imaging with hyperpolarized (3)Helium ((3)He-->). Single-breath, single-bolus visualization of (3)He--> administered to the airspaces is used to analyze nuclear spin relaxation caused by the local oxygen partial pressure p(O(2))(t). We model the dynamics of hyperpolarization in the lung by rate equations. Based hereupon, a double acquisition technique is presented to separate depolarization by RF pulses and oxygen induced relaxation. It permits the determination of p(O(2)) with a high accuracy of up to 3% with simultaneous flip angle calibration using no additional …

Local staging of rectal carcinoma and assessment of the circumferential resection margin with high-resolution MRI using an integrated parallel acquisition technique

Purpose To assess the diagnostic accuracy of integrated parallel acquisition technique (iPAT) in local staging of rectal carcinoma in comparison to conventional high-resolution MRI. Materials and Methods A total of 28 patients with a neoplasm of the rectum and 15 control patients underwent MRI of the pelvis. High-resolution images were acquired conventionally and with iPAT using a modified sensitivity encoding (mSENSE). Image quality, signal-to-noise and contrast-to-noise ratios (SNR, CNR), tumor extent, nodal status, and delineation of the circumferential resection margin (CRM) were compared. In 19 patients with a carcinoma, MR findings were correlated with the histopathological diagnosis.…

CT-Angiographie bei arterieller Verschlußkrankheit: Vergleich von 3 Rekonstruktionsverfahren

Purpose To evaluate different rendering techniques of CT data for the assessment of long vessel segments in peripheral vascular occlusive disease. Material and methods 40 CT angiograms (aortoiliac: n = 20, leg arteries: n = 20) were viewed using three different rendering techniques: 1, maximum intensity projection (MIP); 2, volume rendering (VR); 3, shaded surface display (SSD). CT angiograms were obtained in 6 or 8 projections. Axial cross-section images were analysed using an interactive cine mode. Intraarterial DSA was the standard in all cases. Results The sensitivities for the diagnosis of occlusive disease were 100% (cross-section images), 94% (MIP), 91% (VR) and 93% (SSD). The specif…

MRT bei chronischer Epicondylitis humeri radialis an einem 1,0 T-Gerät - Kontrastmittelgabe notwendig?

T: Is Gd-DTPA administration useful Purpose: Evaluation of the diagnostic value and confidence of contrast-enhanced MR imaging in patients with lateral epicondylitis in comparison to clinical diagnosis. Material and Methods: 42 consecutive patients with clinically proven chronic lateral epicondylitis and 10 ellbow joints of healthy controls have been examined on a 1.0 T MR-unit. Criteria for inclusion in the prospective study were: persistant pain and a failed conservative therapy. The MR protocol included STIR sequence, a native, T 2 -weighted, fat-supressed TSE sequence, and a Flash-2-D sequence. Also, fatsupressed, T 1 -weighted SE sequences before and after administration of Gd-DTPA con…

19F-MRT der Lungenventilation in Atemanhaltetechnik mittels SF6-Gas

Breathhold 19 F-Magnetic Resonance Imaging of Lung Ventilation using SF 6 Gas. Objective: Development of a method to analyze lung ventilation by 19 F-magnetic resonance imaging (MRI) of inspired SF 6 gas during breathhold. Material and Methods: Measurements were performed with a Siemens Magnetom Vision 1.5T scanner using the conventional gradient overdrive. Coronal images of the lung were acquired using ultrafast gradient-echo pulse sequences with TR/TE/α = 1.4 ms/ 0.48 ms/40° without slice selection. With NEX = 200 averages and MA = 32 × 64 raw data matrix, the acquisition time was 9s/image. Higher spatial resolution of 4.7 × 6.3 × 15 mm 3 was obtained with a three-dimensional pulse sequen…

Phantomuntersuchung zur Optimierung der Spiral-CT und 3 D-Rekonstruktion des Tracheobronchialsystems

PURPOSE To optimise three-dimensional spiral CT of the tracheobronchial tree using adequate acquisition and reconstruction parameters for spiral CT of the chest. MATERIAL AND METHODS Qualitative and quantitative assessment of different 3 D reconstructions of two test objects of the tracheobronchial tree depending on section thickness, reconstruction interval, pitch, and reconstruction algorithm used in spiral CT (Siemens, Somatom plus S) of the chest. The frequency of volume and stairstep artifacts was evaluated. The 3 D reconstructions were generated using a seeded VOI-technique (Allegro, ISG). RESULTS Reduction of artifacts was achieved by decreasing section thickness. Increasing overlap …

Verlaufskontrolle des Morbus Crohn: Kann die Hydro-MRT die fraktionierte Magen-Darm-Passage ersetzen?

PURPOSE: To compare the value of hydro-MRI with follow-through examinations in the follow-up of Crohn's disease. METHOD: 22 patients known to be suffering from Crohn's disease were examined via 1.5 T-MR system; an oral contrast examination using 1000 ml of a 2.5% mannitol solution was performed in all patients. T2-weighted TSE sequences and T1-weighted SE sequences were performed before and after the intravenous injection of Gd-DTPA. To reduce movement artifacts caused by peristalsis of the gut, intravenous injection of 40 mg Buscopan was given. The findings of hydro-MRI were compared with the follow-through examinations. RESULTS: In the upper gastrointestinal tract, the follow-through exam…

Klassifikation und Therapie von Endolecks nach endovaskulärer Behandlung von abdominellen Aortenaneurysmen

This article describes the classification of endoleaks after endovascular treatment of abdominal aortic aneurysms, thereby summarizing the most important problems of this endovascular technique. The correct classification of endoleaks is a prerequisite for interdisciplinary discussion. It is indispensable for professional reporting of the pathological findings and for the decision making as to the adequate treatment of endoleaks. Irrespective of the types of stent graft and property of the material, five endoleak types are defined in the literature: leakage at the anchor sites (type I); leakage due to collateral arteries (type II); defective stent grafts (type III); leakage due to porosity …

Funktionsangiographie der kniegelenknahen Arterien: Konsequenzen für die Stentimplantation?

Angiographic studies of the arteries adjoining the knee in 25 patients show extensive kinking and stenoses of the popliteal artery and less frequently of the distal femoral artery during flexion of the knee joint. This is due to the loss of elasticity with increasing age forcing the vessel into a tortuous course during shortening of the pathway of the popliteal artery with knee flexion. Independent of the principle of the different stents available they probably will not increase the contractility of the stented vessel in the longitudinal axis. It is to expect that after implantation of stents into the popliteal artery kinking will occur predominantly in the original segments of the vessel …

CT-Angiographie an einem 16-Schicht-CT zur perioperativen Evaluation der Leberarterien im Vergleich zur MR-Angiographie

Purpose: To evaluate the efficiency of CT angiography (CTA) with 16-row MSCT compared with MR angiography (MRA) in analyzing the arterial anatomy in patients undergoing liver surgery. Materials and Methods: In 30 patients, MRA and CTA studies of the abdominal vessels were reviewed. CT parameters: slice thickness 3 mm; collimation 1.5; reconstruction interval 2 mm (Philips MX 8000 IDT); 120 ml contrast media (400 mg/ml) at a rate of 4 ml/ sec; acquisition of arterial-phase scans. The anatomy of the hepatic artery was evaluated from axial and reconstructed maximum-intensity-projection (MIP) images ("Slab-Viewer", Philips). MR parameters: contrast-enhanced coronal FLASH-3D sequences; slice thi…

Imaging of the lungs using 3he MRI: Preliminary clinical experience in 18 patients with and without lung disease

The purpose of this study was to describe the 3He MRI findings of normal pulmonary ventilation in healthy volunteers and to evaluate abnormalities in patients with different lung diseases. Hyperpolarized 3He gas (300 ml, 3 x 10(5) Pa, polarized to 35-45% by optical pumping, provided in special glass cells) was inhaled by 8 healthy volunteers and 10 patients with different lung diseases. Imaging was performed with a three-dimensional fast low-angle shot (FLASH) sequence (TR = 11.8 msec; TE = 5 msec; transmitter amplitude, 5-8 V; corresponding flip angle, < 5 degrees) in a single breath-hold (22-42 seconds). Clinical and radiological examinations were available for correlation. The studies we…

Sonographie bei Skelettmetastasen - Stellenwert im Vergleich zur Computertomographie und konventionellen Röntgendiagnostik

The value of CT, conventional radiography and ultrasound was compared in 40 patients with 52 skeletal metastases. For superficial lesions, the combination of sonography and conventional radiography was equivalent to CT in showing the extent of bone destruction and soft tissue involvement. As expected sonography was unsatisfactory for deeper lesions. Sonography can provide useful information for planning radiation therapy for superficial lesions, but it does not replace conventional radiography.

Radiologisch assistierte perkutane Gastro-/Enterostomie - Retrospektive Analyse von 90 Eingriffen

PURPOSE To analyse retrospectively the indications, technique and results of radiologically induced gastrostomies or enterostomies. PATIENTS AND METHOD Radiologically assisted gastrostomies or enterostomies were induced in 90 patients, mostly with high grade obstructions due to head and neck tumours or oesophageal tumours. 19/90 patients had had previous resection of the oesophagus or gastric operations. RESULTS A catheter was successfully introduced in all patients. In 11/90 patients this was followed by a two-stage procedure. In 16/90 patients puncture was performed under CT control because of some anatomical peculiarity. Serious complication occurred in 9/90 patients but in only one was …

Bestimmung des Verteilungsvolumens von intrahepatisch injizierten Kontrastmittellösungen: Voruntersuchungen zur intratumoralen Gentherapie

PURPOSE Determination of the intrahepatic distribution volume of two contrast media (CM) by CT-guided application in an ex-vivo and an in-vivo model (pig liver). MATERIAL AND METHODS In pig livers ex-vivo and in-vivo, 131 CT-guided injections of two different CM (Imagopaque(R), Visipaque(R)) were performed using catheters and cannula with and without side-holes and documented by spiral CT. The distribution pattern was assessed visually: interstitial, subcapsular, vascular/tubular, the distribution volume was quantified using a density mask (thresholds 70/400 HE). RESULTS Purely interstitial applications were achieved more frequently in-vivo than ex-vivo (p = 0.001). There were no relevant d…

Preoperative assessment of breast cancer: sonography versus MR imaging.

The purposes of our study were to compare the diagnostic value of whole-breast sonography and MR imaging as adjunctive techniques to mammography and to determine whether MR imaging should be used routinely in the preoperative assessment of patients with suspected breast cancer.. One hundred four women (age range, 34-84 years; mean age, 60 years) with findings highly suggestive of malignancy in the breast were examined with mammography, sonography, and dynamic MR imaging before undergoing surgery. All visualized suspicious lesions were correlated histologically. The diagnostic relevance of sonographic and MR imaging findings was compared with the diagnostic value of the findings of clinical …

Flussquantifizierung in Koronar- und Bypass- gefäßen mit der MR-Phasenkontrasttechnik

Ziel: Es sollte die Genauigkeit der MR-Phasenkontrastmethode zur Ermittlung des Flusses in Koronararterien und koronaren Bypassgefasen bestimmt werden. Material und Methode: Die MRT-Flussmessungen von 12 Patienten mit 22 Bypassgefasen wurden mit intraoperativ mittels Ultraschalldurchflussmethode bestimmten Flussen verglichen. Praoperativ wurden zusatzlich Flussmessungen in 28 Koronararterien von 20 Patienten durchgefuhrt. Zur MRT-Flussmessung wurde eine segmentierte 2D-Flash-Sequenz verwendet, die eine zeitliche Auflosung von 110 bzw. 125 ms aufwies. Dies ermoglichte die Akquisition von 6–8 Bildpaaren pro Herzzyklus. Ergebnisse: Es bestand eine signifikante Korrelation zwischen den Ergebnis…

Spiral-Computertomographie der Mamma

Aim To evaluate the use of spiral CT in the diagnosis of breast lesions. Material and methods 93 female patients with suspicious or uncertain mammographic findings were examined by CT before and after contrast enhancement according to the following practical method: table movement, 6 mm/s, slice thickness 6 mm, increment 4 mm, contrast 200 ml, injection rate 3 ml/s, scan start 50 s after the beginning of the injection. Histological confirmation was present in 85 patients. Results All 44 invasive carcinomas were recognised. They were characterised by intensive focal contrast uptake. Only 2 out of 7 intraductal carcinomas were not shown by CT. 36 out of 38 benign lesions were correctly diagno…

Gadolinium-DTPA (Magnevist®) als Kontrastmittel für die arterielle DSA

16 DSA investigations using intra-arterial Gd-DTPA were performed on 12 patients. The contrast medium was administered either as a 0.5 molar gadolinium solution (commercially available) or diluted with distilled water to a 0.2-0.4 molar gadolinium solution. The injection was made either by pressure injector or by hand. The aortic arch, abdominal aorta and pelvic and lower limb arteries were examined. 14 of the 16 procedures were diagnostically adequate, but compared with iodinated contrast materials, contrast was less marked. There were no cardiovascular, neurological or allergic side effects. Three patients suffered a feeling of heat and one patient had mild pain during the injection. Even…

MR-tomographische Funktionsanalyse des linken Ventrikels

The following contribution presents a continuous MRT analysis of the contraction and relaxation processes of healthy left ventricles giving reference values for contraction and relaxation velocities. For the total ventricle we have Vsyst. r. total = 342 +/- 47% LVEDV/sec and Vdiast. r. total = 303 +/- 59% LVEDV/sec. In relation to the end-diastolic (tomographic) volume (EDSV) significantly greater changes in volume per unit of time were measured apically compared to basal (systolic: 411 +/- 89% EDSV/sec apical vs 261 +/- 35% EDSV/sec basal; diastolic: 810 +/- 145% EDSV/sec apical vs 245 +/- 70% EDSV/sec basal). Occurrence of the end-systolic minimal volumes of apical tomographic layers was …

Software zur automatischen Quantifizierung von Belüftungszuständen bei akutem Lungenversagen in dynamischen CT-Aufnahmen der Lunge1

Purpose: Density measurements in dynamic CT image series of the lungs allow one to quantify ventilated, hyperinflated, and atelectatic pulmonary compartments with high temporal resolution. Fast automatic segmentation of lung parenchyma and a subsequent evaluation of it's respective density values are a prerequisite for any clinical application of this technique. Material and Methods: For automatic lung segmentation in thoracic CT scans, an algorithm was developed which uses (a) different density masks, and (b) anatomic knowledge to differentiate heart, diaphragm and chest wall from ventilated and atelectatic lung parenchyma. With Animal Care Committee approval, the automated technique was t…

CT angiography versus intraarterial digital subtraction angiography for assessment of aortoiliac occlusive disease.

The purpose of this study was to evaluate the accuracy of CT angiography (CTA) with a single helical acquisition for assessment of stenoses and occlusions of the iliac arteries.In our prospective study, intraarterial digital subtraction angiography and IV CTA were performed from the suprarenal aorta to below the femoral bifurcation in 30 patients with vascular occlusive disease. Maximum-intensity-projection images in multiple views were also obtained. The accuracy of CTA with and without analysis of axial images was determined.Sensitivity and specificity of CTA were 100% for iliac artery occlusions with a confidence interval 85-100% and 97-100%, respectively. When axial scans were interpret…

Quantification of myocardial blood flow and blood flow reserve in the presence of arterial dispersion: A simulation study

Myocardial blood flow (MBF) can be quantified using dynamic T1-weighted MRI of diffusible tracers and a mathematical model of underlying vasculature. Quantification of MBF by means of T1- weighted MRI requires knowledge of the arterial input function (AIF). The AIF can be estimated from the left ventricular (LV) cavity. However, dispersion may occur between the LV and the tissue of interest because of the laminar blood flow profiles, branching of venules, and because of stenosis. To evaluate the influence of dispersion on the results of MBF quantification, a simulation study was performed. The dispersion was described as a convolution of the AIF with an exponential residue function. Synthet…

3 He-MRI-based vs. conventional determination of lung volumes in patients after unilateral lung transplantation: a new approach to regional spirometry

Background: To use 3Helium (3He)-MRI in patients with unilateral lung grafts to assess the contributions of graft and native lung to total ventilated lung volume, and second to compare conventional measurements of intrapulmonary gas volume (spirometry, body plethysmography) with image-based volumetry of ventilated lung parenchyma visualized by hyperpolarized 3He-MRI. Methods: With Ethics Committee approval, five patients with single lung transplantation (SLTX) for idiopathic pulmonary fibrosis (IPF) underwent both conventional pulmonary function testing (PFT) and 3He-MRI of the lung. Intrapulmonary gas volume (GV) during the inspiratory breathhold for 3He-MRI was calculated from measured fu…

Hemodynamic Effects of Nonionic Contrast Bolus Injection and Oxygen Inhalation During Pulmonary Angiography in Patients With Chronic Major-Vessel Thromboembolic Pulmonary Hypertension

Background Pulmonary angiography is the gold standard for the diagnosis of chronic thromboembolic pulmonary hypertension; however, major complications have been reported. This study evaluates the hemodynamic effects of direct pulmonary nonionic contrast bolus injection and oxygen inhalation in patients with chronic thromboembolic pulmonary hypertension. Methods and Results In 33 patients, hemodynamic parameters were measured after oxygen inhalation and during bolus injection of nonionic contrast medium in a control group (group 1, n=11), in a group of patients with moderately severe pulmonary hypertension (group 2, n=9), and in a group with severe pulmonary hypertension (group 3, n=13). Ox…

Spiral-CT zum Nachweis von Koronararterienverkalkungen und Vorhersage einer koronaren Herzerkrankung - Vergleich zur Durchleuchtung und Koronarangiographie

PURPOSE Evaluation of clinical relevance of coronary calcifications detected by helical CT. Evaluation of congruence with fluoroscopy (FS) and coronary angiography. Comparison with studies reporting on application of ultrafast computed tomography. MATERIALS AND METHODS 40 patients underwent helical CT (2 mm slice thickness, table-feed 3 mm/s). Coronary angiography and FS were performed in usual technique. Stenosis and calcifications were evaluated semiquantitatively. RESULTS 28 of 28 stenoses > or = 75% were detected via helical CT by evaluation of calcification (FS: 19). One non-detected solitary stenosis was calculated as 40%. FS did not detect 4 cases with 2-vessel and 3-vessel disease e…

Outcome Analysis and Rational Management of Enhancing Lesions Incidentally Detected on Contrast-Enhanced MRI of the Breast

The purpose of our study was to assess the prevalence, characteristics, and clinical consequence of incidentally detected enhancing lesions on MRI of the breast. SUBJECTS AND METHODS. MRI of the breast (1.0-T scanner, dynamic gadolinium-enhanced T1-weighted three-dimensional gradient-echo sequence, double breast coil) was performed on 1273 women for different indications. Enhancing incidental lesions were defined as enhancing lesions on MRIs that were not expected from findings on the previous conventional imaging. They were classified in five assessment categories using a scoring system based on morphologic and kinetic enhancement characteristics. Detection of enhancing incidental lesions …

Analysis of discrete and continuous distributions of ventilatory time constants from dynamic computed tomography.

In this study, an algorithm was developed to measure the distribution of pulmonary time constants (TCs) from dynamic computed tomography (CT) data sets during a sudden airway pressure step up. Simulations with synthetic data were performed to test the methodology as well as the influence of experimental noise. Furthermore the algorithm was applied to in vivo data. In five pigs sudden changes in airway pressure were imposed during dynamic CT acquisition in healthy lungs and in a saline lavage ARDS model. The fractional gas content in the imaged slice (FGC) was calculated by density measurements for each CT image. Temporal variations of the FGC were analysed assuming a model with a continuous…

Ergebnisse der kontrastverstärkten MR-Angiographie der aortoiliakalen Gefäße mit einem 1-molaren Kontrastmittel bei 1,0 T: Vergleich zur i. a. DSA

PURPOSE To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE-MRA) using a 1.0 molar contrast agent at 1.0 T for the diagnosis of abdominal aortic aneurysms and stenoses of renal or iliac arteries in comparison to intraarterial digital subtraction angiography (DSA). MATERIALS AND METHODS A total of 19 patients with the suspicion of abdominal aortic aneurysm or stenosis of renal or iliac arteries were examined with CE-MRA at 1.0 T. Intra-arterial DSA served as reference in all cases. After test bolus tracking, 10 or 8 ml of the 1.0 molar contrast agent Gadobutrol corresponding to a dose of 0.1 - 0.15 mmol/kg bw were injected and imaging performed using a FLASH-3D sequen…

Dynamische Bildgebung der Nasenhaupthöhle und der Nasennebenhöhlen im MR mittels polarisiertem 3Helium

sinuses with polarized 3 helium MRI. Purpose: Reduced or blocked ventilation of the paranasal sinuses is probably the most important factor in the development of sinusitis. Recently, the use of optically polarized noble gas isotopes has attracted increasing interest for use in a variety of promising MR applications. The aim of this study was to test the feasibility of imaging and visualization ventilation of the nasal cavity and paranasal sinus in MR by inhalation of hyperpolarized 3 helium. The goal was to evaluate ventilation defects of the paranasal sinuses. Volunteers and Methods: Three volunteers were enrolled in the study. 3 Helium was polarized to 40-50% by direct optical pumping. 30…

CT after enucleation of renal cell carcinoma.

Computed tomography (CT) was performed in 28 patients 2 weeks to 120 months after enucleation of renal cell carcinoma. The postoperative defect could be exactly localized in all patients. A wedge-shaped (N = 11) or concave (N = 9) morphology was typical. No dependence between morphology of the defect and localization or size of the tumor or the operative technique was observed. The defects were smaller (1.9 cm) than the original prominent tumors (3.6 cm). Defect size was dependent on the operative technique: closure by suture of the renal capsule in smaller defects or by fat flap in larger ones. Postoperative hematomas or delayed perfusion in the adjacent parenchyma were seen in five patien…

Druckentlastung im Aneurysmasack nach endovaskulärer Therapie von Aortenaneurysmen*

PURPOSE Stent grafting of aortic aneurysms should result in relief of pressure within the excluded aneurysmal sac, however confirming data are not available. This study evaluates the intra-extraluminal pressure translation and translation of maximum pressure increase (dp/dtmax) into the excluded aneurysmal sac after endovascular treatment of experimental aortic aneurysms. MATERIALS AND METHODS Experimental autologous aneurysms were created surgically using a patch from the sheath of the rectus abdominis muscle in 12 mongrel dogs. After 12 weeks reconvalescence, endovascular treatment was performed viafemoral access using dacron-covered nitinol stents. Spiral CT and angiography were performe…

Bildgebende Diagnostik der Peritonealkarzinose

Two hundred and eighty-seven radiological and sonographic examinations in 142 patients with confirmed peritoneal carcinosis were evaluated retrospectively. The examinations included abdominal films (19), infusion urograms (20), contrast examinations of the intestine (26), small bowel enemas (2), double-contrast examinations of the colon (40), demonstrations with water-soluble contrast (6), sonographies (80) and CTs (96). CT and colonic double-contrast studies were complementary and valuable methods for diagnosing peritoneal carcinosis and should both be used.

Flip angle considerations in (3)helium-MRI.

3Helium-MRI ((3)He-MRI) can be used for analysis of lung function, e. g. dynamic imaging of ventilation and gas diffusion within the lung, assessment of intrapulmonary oxygen concentrations and their time course. During imaging, the irreversible signal loss due to depolarizing radio frequency excitations can be described using the flip angle (FA) alpha. This parameter has to be quantified in order to account for it during quantitative assessment of the (3)helium signal intensity and its temporal development. This technical report reviews two different methods to determine alpha. Limitations and possible error sources of each method are discussed.

Assessment of coronary artery bypass grafts: value of different breath-hold MR imaging techniques.

Our aim was to evaluate the patency of coronary artery bypass grafts and to detect graft stenosis using different breath-hold MR imaging techniques.Twenty-two patients with 59 grafts (14 internal mammary artery grafts and 45 saphenous vein grafts) and 76 distal anastomoses (singular and sequential grafts) were studied using a 1.5-T scanner. A two-dimensional T2-weighted breath-hold half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence and a three-dimensional breath-hold contrast-enhanced MR angiography sequence (fast imaging with steady-state free precession) were performed. For MR angiography, a bolus of 20 ml of gadopentetate dimeglumine was used. Time delay for contrast i…

Stellenwert der Spirometertriggerung für die hochauflösende Computertomographie der Lunge in Inspiration und Exspiration

PURPOSE To compare mean lung density (MLD) of paired inspiratory and expiratory thin-section CT scans acquired after patient instruction or using spirometric gating. MATERIALS AND METHODS 21 patients (13 m, 8 f. median age 59 years, two with normal lung function, 15 with obstructive, 4 with restrictive impairment) underwent thin-section CT. Paired inspiratory and expiratory scans were performed in the upper, middle and lower lung fields. They were acquired after automatic patient instruction with constant intervals between instruction and scan. Spirometrically gated scans were acquired within 4 days at 80% and 20% of vital capacity (VC) which has been determined on the CT scanner in supine …

Die dynamische 31-Phosphor-Magnetresonanz-Spektroskopie des M. quadriceps: Einfluß von Geschlecht und Alter auf spektroskopische Parameter

PURPOSE 31P-MRS is used to assess the influence of sex und age on quadriceps muscle metabolism before and after exercise. MATERIALS AND METHODS 32 healthy volunteers (15 women, 17 men, mean age: 38 +/- 17 yrs.) were examined by dynamic phosphorus-31 (31P) magnetic resonance spectroscopy (MRS). In the magnet, the quadriceps muscle was stressed by an isometric und an isotonic form of exercise until exhaustion, respectively. RESULTS Resting conditions: With increasing subjects' age, the ratio beta-adenosine triphosphate/total phosphate decreased (r = -0.37; p = 0.02). With increasing subjects' age, the ratios inorganic phosphate/phosphocreatine (r = 0.79; p = 5 x 10(-8), phosphomonoester/beta-…

Early detection of pneumonia in febrile neutropenic patients: use of thin-section CT.

The purpose of this study was to evaluate the usefulness of thin-section CT for early detection of pneumonia in neutropenic patients with an unknown site of infection and normal or nonspecific findings on chest radiographs.Eighty-seven patients with febrile neutropenia that persisted for more than 2 days despite empiric antibiotic treatment underwent 146 prospective examinations. If findings on chest radiographs were normal (n = 126) or nonspecific (n = 20), thin-section CT (1-mm collimation, 10-mm increment) was done. If thin-section CT scans showed opacities, bronchoalveolar lavage was recommended.Findings on chest radiographs were nonspecific for pneumonia in 20 (14%) of 146 cases, and C…

Volumetry of Ventilated Airspaces by 3He MRI

To develop a validated post-processing routine for volumetry of the ventilated airspaces by 3He MRI.3Helium MRI and pulmonary function tests were performed in seven healthy volunteers. After segmentation of ventilated airspaces, their volumes were calculated. Functional residual capacity (FRC) was used as a reference. For comparison of absolute volumes, correction factors were evaluated.Mean lung volume (+/- standard deviation) calculated from 3He MRI was 4,082 +/- 908 mL and mean FRC was 3,696 +/- 1166 mL, with a mean difference of 386 mL (r = 0.88). After correction for the relative pulmonary air content (factor 0.82), posture (0.72), and the individual tidal volume, 3He MRI volume was 3,…

Helical computed tomographyangiography: Technical considerations and clinical applications

Abstract A combination of volume acquisition techniques (helical CT), dedicated protocolsfor bolus injections of contrast medium, and postprocessing modalities have paved the way for computed tomography (CT) angiography. To obtain optimum results the collimation must be adapted to the vascular territory of interest, and the reconstruction of overlapping source images from the volume data set is advantageous for further postprocessing. Strong intravascular opacification is indispensable for the evaluation of vascular abnormalities and pathology and is also helpful for image postprocessing, where different modalities can be applied: multiplanar reconstruction, maximum intensity projection, se…

MR-Tomographie bei Hodenprozessen

The value of T1-weighted sequences after intravenous administration of Gd-DTPA and of T2-weighted sequences was compared in 43 patients suspected of having scrotal abnormalities. T2-weighted sequences gave better demonstration of the tunica albuginea and better contrast between tumor and parenchyma. The two techniques were equally sensitive for demonstrating testicular tumors but orchitis was better demonstrated on the contrast enhanced sequences. Motion artifacts were less marked in the T1-weighted sequences with contrast enhancement. In selected cases, contrast enhancement may be a valuable addition to native protocols. Our experience has indicated that MRI provides specific findings in c…

Das Verhalten der Kollateralen bei der perkutanen transluminalen Angioplastie

The fate of 106 collaterals was investigated following percutaneous transluminal dilatation of 113 stenoses and occlusions. Following dilatation, 78% of collaterals were unchanged and 22% could no longer be demonstrated. The success of the dilatation had no bearing on the fate of the collaterals. Collaterals beginning or ending in a dilated portion of vessel disappeared more frequently (30%) than the others (11%). Following five dilatations, some vessels were demonstrated in the area of stenosis, which had not been demonstrated previously. Evidently local events, such as displacement of arteriosclerotic plaques may lead to occlusion or reopening of vessels. Remaining collaterals may be of g…

Value of contrast-enhanced MR angiography and helical CT angiography in chronic thromboembolic pulmonary hypertension.

The aim of this study was to evaluate the diagnostic value of contrast-enhanced MR angiography (ce MRA) and helical CT angiography (CTA) of the pulmonary arteries in the preoperative workup of patients with chronic thromboembolic pulmonary hypertension (CTEPH). The ce MRA and CTA studies of 32 patients were included in this retrospective evaluation. Image quality was scored by two independent blinded observers. Data sets were assessed for number of patent segmental, subsegmental arteries, and number of vascular segments with thrombotic wall thickening, intraluminal webs, and abnormal proximal to distal tapering. Image quality for MRA/CTA was scored excellent in 16 of 16, good in 11 of 14, m…

Magnetic resonance imaging in primary cerebral neuroblastoma

Koronare Bypassdiagnostik mit CT und MRT - eine Bestandsaufnahme

The limited lifetime and the correlation between graft occlusion and recurring symptoms underline the need for repeated imaging of coronary artery bypass grafts. CT and MRI allow for non-invasive imaging of coronary bypasses with high accuracies concerning the patency of these vessels. Multidetector CT seems to be the CT technique of choice, especially after the introduction of 16 slice CT scanners for morphologic assessment of coronary artery bypass grafts. Compared with MRI, CT is a robust technique for assessment of cardiac anastomoses, native coronary arteries, and for the detection of graft stenoses. MRI, however, is able to deliver functional information about the grafts and the recip…

Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography in a Patient With Chronic Thromboembolic Pulmonary Hypertension Before and After Thromboendarterectomy

The patient was a 69-year-old man with progressive dyspnea during the previous 5 years and no history of thromboembolic events. By means of spiral CT scanning and multiplanar digital subtraction angiography of the pulmonary arteries, chronic thromboembolic pulmonary hypertension was diagnosed. Mean pulmonary artery pressure and pulmonary vascular resistance were elevated to 46 mm Hg and 890 …

Computertomographie der Nieren nach Tumorenukleation

Two weeks to 120 months after enucleation of renal tumours the postoperative defects were correctly localized by renal computed tomography in 34 patients. Typical defect morphology was either wedge-shaped or concave. No dependence on tumour localization, tumour size, operative technique or a certain surgeon was observed. The cortical defects were smaller (mean 2.0 cm) than the original, prominent tumours (mean 3.4 cm). In small defects without tension suture of the capsule is sufficient, leading to minor defects. Larger defects were closed with a retroperitoneal or free peritoneal fat flap resulting in larger residual defects. In case of intra- or postoperative bleeding, CT could demonstrat…

Cerebral and spinal MR-findings in patients with postrepair myelomeningocele

In 114 patients with postrepair myelomeningocele MRI of the spine was performed. Tethered cord (89%) and associated malformations (syrinx, lipoma etc.) (33%) were the most important findings. Additional MRI scans of the head (44 patients) revealed numerous further anomalies. Arnold Chiari malformation was found in 76% of the patients (ACM I: 32%, ACM II: 44%). In the ACM II group compression of lower cranial nerves, brain stem, and cerebellum can lead to considerable neurologic symptoms. Therefore in patients with progressive neurologic dysfunction a complete investigation of the whole spine and brain is necessary. MRI proves to be the diagnostic procedure of choice in patients with dysraph…

Diabetes and Peripheral Arterial Occlusive Disease

The purpose of this study was to compare contrast-enhanced three-dimensional MR angiography with conventional digital subtraction angiography (DSA) for identifying and evaluating arteries of the distal calf and foot in diabetic patients with severe arterial occlusive disease who will undergo distal bypass surgery.Twenty-four feet of 24 consecutive patients with diabetes and limb-threatening lower extremity ischemia were prospectively imaged using an ultrafast three-dimensional fast low-angle shot sequence on a 1.5-T MR scanner. All patients also underwent DSA of the diseased extremity within 5 days. Images were interpreted in a randomized manner by two observers in conference. Each lower ex…

Diagnosis of aortic dissection: the value of transesophageal echocardiography.

Using the transesophageal approach the descending part of the aorta can be imaged by two-dimensional enchocardiography in cross sections comparable to computer tomograms. The value of combined transesophageal and transthoracic echocardiography was evaluated in 53 patients who were studied consecutively from 1983 to 1986 with symptoms of aortic dissection and compared with computed tomography, angiography, surgery and/or autopsy. In all patients the transthoracic aorta could be visualized and the dissection could be classified according to DeBakey: in 9 of 29 patients (34%) type I dissection, in 4 (14%) type II dissection and in 16 (55%) type III dissection was found. Operation was carried o…

Leber-CT mit portal-venöser Kontrastmittelgabe

Contrast administration through the superior mesenteric or splenic arteries provided additional information in 22 out of 31 patients, when compared with intravenous contrast bolus for CT of the liver. In 11 patients, the demonstration of a tumour lead to a change in treatment. False positive findings occurred in four of the 31 patients. In 2 patients intrahepatic lesions were overlooked, but were found during angiography carried out at the same examination. The diagnosis of intrahepatic space-occupying lesions is discussed as well as the CT appearances of portal-venous liver perfusion.

Hadamard NMR imaging with slice selection

Stochastic NMR imaging is one of the less common NMR imaging techniques. Nevertheless, stochastic rf excitation is characterized by some remarkable features: the rf excitation power is at least two orders of magnitude lower in comparison to conventionally pulsed NMR imaging schemes. Thus, the technique is of interest for imaging of large objects. The systematic noise inherent in images obtained with random noise excitation has been eliminated by using pseudorandom noise together with Hadamard transformation for data evaluation. Data acquisition times are comparable to those of ultrafast imaging techniques. For slice selection, z magnetization is destroyed outside the slice region with speci…

Lack of mutagenic and co-mutagenic effects of magnetic fields during magnetic resonance imaging

Mutagenic and co-mutagenic effects of static, pulsed bipolar gradient, and high-frequency magnetic fields, as well as combinations of them, were examined using the Ames test. The Ames test using Salmonella typhimurium bacteria, wild-type strain RTA, preincubation assay, without metabolic activation, was performed. All combinations of magnetic fields were tested with and without co-exposure to N-methyl-N′-nitro-N-nitrosoguanidine and benzo[a]pyrene-4,5-oxide, ethylene oxide, carboplatin, or cisplatin. As expected, chemical mutagens caused a clear-cut increase of the revertants in the Ames test. However, neither the static fields nor a combination of a static magnetic field with the time-vary…

Helium-3-MRT der Lungenventilation: Erste klinische Anwendungen

PURPOSE: of the study is the visualisation of normal pulmonary ventilation in healthy volunteers and the evaluation of abnormalities in patients with different lung diseases using 3He magnetic resonance imaging (3He-MRI). MATERIAL AND METHODS: Hyperpolarized 3He gas (V = 300 ml, p = 3 x 10(5) Pa, polarised to 35-45% by optical pumping, provided in special glass cells) was inhaled by eight healthy volunteers and ten patients with different lung diseases. A 3D FLASH sequence (TR = 11.8 ms; TE = 5 ms; matrix 144 x 256, FOV 350 mm, section thickness 7-10 mm, coronal orientation) was performed in a single breath-hold (22-42 s). Clinical and radiological examinations were available for correlatio…

Blutungen des Dünn- und Dickdarms: Radiologische Diagnostik und Therapie

Multi-Slice CT (MSCT) in Cardiac Function Imaging: Threshold-Value-Supported 3D Volume Reconstructions to Determine the Left Ventricular Ejection Fraction in Comparison to MRI

Evaluation eines neuen Softwareassistenten zur automatischen Volumenbestimmung von intrahepatischen Tumoren

Purpose: Computed tomography has become the preferred method in detecting liver carcinomas. The introduction of spiral CT added volumetric assessment of intrahepatic tumors, which was unattainable in the clinical routine with incremental CT due to complex planimetric revisions and excessive computing time. In an ongoing clinical study, a new software tool was tested for the automatic detection of tumor volume and the time needed for this procedure. Materials and Methods: We analyzed patients suffering from hepatocellular carcinoma (HCC). All patients underwent treatment with repeated transcatheter chemoembolization of the hepatic arteria. The volumes of the HCC lesions detected in CT were m…

Das Pulmonalarteriensarkom - Prä- und postoperative radiologische Befunde bei der Tumorerstmanifestation und beim Rezidiv

Purpose Primary pulmonary artery sarcomas are very rare tumors. Their diagnosis is difficult due to their unspecific symptoms. Still, an early preoperative diagnosis is the only possibility for a potential therapy. Patients and methods 4 pre- and 5 postoperative CT- and three pre- and one postoperative MRT-examination(s) have been evaluated with respect to surgical and histological findings. Results The presence of a convex intraluminal bulging mass spreading mostly from the pulmonary trunc continuously into the peripheral pulmonary artery branches the filling and dilatation of the vessels, the tumor's inhomogeneity indicating hemorrhages and necrosis and the appearance of intrapulmonary no…

Kontrastmittelgestützte 3D-MR-Angiographie der Becken- und Beinarterien mit automatischer Tischverschiebung bei 1,0 Tesla

PURPOSE Assessment of the value of contrast-enhanced MR angiography (ceMRA) using an automatic tracking technique at 1.0 Tesla in comparison with digital subtraction angiography (DSA) of the pelvic and lower limb arteries. MATERIALS AND METHODS In 15 patients with peripheral arterial occlusive disease a ceMRA (3D FLASH, TR/TE = 6.2/2.3 ms, Flip angle alpha = 30 degrees, Matrix 170 x 256) using a new automatic tracking technique was accomplished. The reference method was DSA. Twenty-one vessel segments of each patient were graded as normal, stenosed (> 50%) or occluded. Image material was evaluated independently by two radiologists. RESULTS In comparison, the interobserver agreement showed a…

Bestimmung der myokardialen Perfusionsreserve bei KHK-Patienten mit der kontrastmittelverstärkten MRT: Ein Vergleich zwischen semiquantitativer und quantitativer Auswertung

OBJECTIVE Comparison between two semiquantitative methods and a quantitative evaluation of myocardial blood flow (MBF) for assessment of myocardial perfusion reserve (MPR) in patients with CAD. MATERIAL AND METHODS 9 patients with coronary stenoses > 50 % were examined with an ECG-gated Saturation Recovery Turbo FLASH sequence by using Gd-DTPA as contrast agent (CA). The entive measurements were performed both during rest and hyperemia induced by adenosine. The up-slopes of the signal-time S(t) curves in the myocardium and left ventricular (LV) cavity were evaluated by a linear fit. MPR was calculated from the original up-slopes of the myocardial S(t) curves and from the up-slopes, which we…

Die Lungentuberkulose – aktuelle radiologische Diagnostik einer alten Krankheit

Inzidenz. Abnehmende Inzidenzen aktiver Tuberkulose in den Industrielandern haben diese Erkrankung aus dem Bewusstsein vieler verdrangt. Dennoch stellt die Tuberkulose weiterhin weltweit die am haufigsten zum Tode fuhrende Infektionskrankheit dar. In den Industrielandern tragen Faktoren wie Einwanderungsbewegungen, zunehmende Verarmung und die Zunahme immunsupprimierter Patienten, insbesondere durch die HIV-Epidemie, dazu bei, dass ein Reservoir fur die Tuberkulose aufrecht erhalten wird. Diagnose. Eine fruhzeitige Diagnose ist wegen der spezifischen Therapiemoglichkeiten entscheidend fur den Krankheitsverlauf; im Falle von multiresistenten Stammen ist sie wichtig zur Verhinderung einer wei…

Automatische Klassifikation der Lebersegmente nach Couinaud: Entwicklung eines neuen Algorithmus und Evaluierung an Spiral-CT-Datensätzen

Purpose: To develop a software tool that analyzes the anatomy of the portal vein branches and assigns segmental and subsegmental branches according to Couinaud's classification system and to evaluate its accuracy. Materials and Methods: The algorithm was developed in C++ on a PC. The algorithm recognizes the three major branching patterns of the portal vein. Segmental and subsegmental branches are assigned to 8 segments following Couinaud and encoded by 8 colors. The software was evaluated using CT data sets of 39 patients. After the individual segmental anatomy of each patient was determined by an experienced radiologist, automatic classification was performed and the results were compared…

No influence of magnetic fields on cell cycle progression using conditions relevant for patients during MRI.

The purpose of this study was to examine whether exposure to magnetic fields (MFs) relevant for magnetic resonance imaging (MRI) in clinical routine influences cell cycle progression in two tumor cell lines in vitro. HL60 and EA2 cells were exposed to four types of MFs: (i) static MF of 1.5 and 7.05 T, (ii) extremely low frequency magnetic gradient fields (ELFMGFs) with ± 10 mT/m and 100 Hz, as well as ± 100 mT/m and 100 Hz, (iii) pulsed high frequency MF in the radiofrequency (RF) range (63.6 MHz, 5.8 μT), and (iv) a combination of (i–iii). Exposure periods ranged from 1 to 24 h. Cell cycle distribution (G0/G1, S, and G2/M phases) was analyzed by flow cytometry. Cell cycle analysis did not…

Fokal-noduläre Hyperplasie der Leber bei 930 Patienten

Analysis of 930 patients with focal nodular hyperplasia of the liver (FNH), including 23 seen by the authors, showed the following results: 82.2% of patients were female, 37.8% of these had taken female steroidal hormones. There was no preference for a particular lobe of the liver. 57.7% of FNH were subcapsular, 33.7% were intrahepatic and 8.8% were pedunculated. Average size was 5.9 cm, 80.8% of the patients were asymptomatic. In 93.5% (115 out of 123) a space-occupying lesion in the liver could be demonstrated by sonography. In 13%, second or multiple tumours were missed by sonography. CT without enhancement demonstrated FNH in 90.4% (94 out of 104 patients). A rapid, marked increase in d…

Repräsentiert der HRCT-Emphysemindex die gesamte Lunge?

Purpose: Comparison of emphysema index derived of thin section MD-CT of the entire lung volume and HRCT, simulated by calculation of every twentieth image of the whole data-set. Materials and Methods: Pulmonary emphysema was quantified by semiautomatic, segmentation of lung borders and assessment of lung volume and emphysema volume within these borders. The emphysema index (pixel index) was calculated. Statistical analysis was done by the sign-test and Bland-Altman-analysis. Results: Median lung volume, emphysema volume and emphysema index are significantly higher in simulated HRCT. Median lung volume (emphysema volume) calculated by HRCT is 5118 ml (407 ml) and 5040 ml (367 ml) calculated …

Spiral CT of bronchial arteries in chronic thromboembolism.

OBJECTIVE: Computed tomography study of bronchial artery anatomy and evaluation of dilatation and tortuousity as indicators for pulmonary hypertension and surgical risk in patients with chronic thromboembolism were performed. MATERIALS AND METHODS: We retrospectively reviewed contrast-enhanced, thin section spiral CT scans of 39 patients undergoing pulmonary thromboendarterectomy. Findings were compared with mean pulmonary artery (PA) pressure in all, postoperative mortality in 33, and postoperative CT in 5 patients. Twenty patients without pulmonary hypertension served as controls. RESULTS: In the pulmonary hypertension group, 50 bronchial arteries were observed in 30 of 39 patients. Their…

Computertomographie nach extrakorporaler Stoßwellenlithotripsie (ESWL) der Nieren

In 105 patients CT studies were done prospectively after renal ESWL with a second generation lithotripter. 33 (31%) of the patients had renal oedema (n = 8), renal (n = 20) or extrarenal (n = 31) bleeding. Three of the 23 patients who had a three year follow-up had chronic renal changes, 10 had renal stones. As blunt renal trauma can be the cause of renal hypertension a longterm follow-up is necessary in ESWL patients, particularly if there was renal bleeding after treatment. Further studies are needed to determine the exact risk of renal hypertension after ESWL.

Multiple renal aspergillus abscesses in an AIDS patient: contrast-enhanced helical CT and MRI findings.

Renal insufficiency or allergic reactions for X-ray contrast agents are frequent limitations in immunocompromised hosts such as neutropenic or AIDS patients. Due to a better tolerance of contrast agents in MRI, this technique is well suited for investigation of parenchymal organs. We demonstrate an allergic AIDS patient who presented with fever and flank pain. At sonography, anechoic renal lesions were supposed to be non-complicated cysts; however, on T2-weighted MRI, the center was of high signal. Dynamic contrast-enhanced MRI of the kidneys demonstrated an enhancing rim with ill-defined margins. The lesions were supposed to be multiple bilateral abscesses. Due to the multiple dynamic cont…

Diagnostik der primär sklerosierenden Cholangitis: prospektiver Vergleich von MR-Cholangiographie mit endoskopisch retrograder Cholangiographie

PURPOSE To assess the accuracy of MR cholangiography (MRC) in the diagnosis of primary sclerosing cholangitis (PSC) in comparison to endoscopic retrograde cholangiography (ERC). METHOD 20 patients with PSC were examined by ERC and MRC (1.0 T, HASTE sequence). Visualization and pathologic changes of the extra- and intrahepatic bile ducts were evaluated with both methods. RESULTS Mural irregularities of the common bile duct were seen with MRC in 6/7 cases, stenoses and dilatation of the common bile duct were detected correctly in all patients. Diffuse, multifocal strictures of the intrahepatic bile ducts were the most common intrahepatic findings and correctly diagnosed in almost all patients…

Detection of dissection of the aortic intima and media after angioplasty of coarctation of the aorta. An angiographic, computer tomographic, and echocardiographic comparative study.

Balloon coarctation angioplasty (BCA) was performed in eight patients (five male and three female) who were 14-49 years old (mean, 27.3 years) with isolated discrete unoperated coarctation of the aorta (n = 7) and postoperative recoarctation (n = 1). BCA was successful in seven of eight patients, resulting in a decrease in the gradient (64 +/- 19 to 16 +/- 13 mm Hg, p less than 0.01), an increase in the diameter at the coarctation site (0.9 +/- 0.4 to 1.6 +/- 0.4 mm, p less than 0.01). Follow-up (6 months) has demonstrated continued gradient relief (6 +/- 9 mm Hg) and diameter increase (1.6 +/- 0.2 cm). Monitoring was performed by transesophageal echocardiography (TEE) during BCA, and befor…

Fokussuche bei neutro- penischem Fieber

Magnetresonanztomographische Befunde nach Resektionsarthroplastik des Humeruskopfes

PURPOSE The resection of the humeral head is normally carried out only with respect to four-part and dislocation fractures in elderly patients. The purpose of this study was to examine whether there is a correlation between the clinical results and the MRI findings. MATERIAL AND METHODS 8 patients underwent clinical and MR examination two to 6 years after resection. RESULTS A cartilage-like tissue formation between the remaining humeral head and the glenoid fossa, with signal intensities comparable to hyalin cartilage was found in all patients. CONCLUSION The good functional results following resectional surgery of the humeral head can partially be related to new substitute cartilage result…

Möglicher Nutzen und Auswirkung einer Lipiodolmarkierung auf die Histologie beim hepatozellulären Karzinom

Purpose: To assess the benefit and the effect of intraarterial lipiodol application on histological analysis of patients suspected of having HCC. To determine whether lipiodol marking leads to a better biopsy result and how lipiodol or a transarterial chemoembolization influences the histological diagnosis. Materials and Methods: Two groups of patients were examined. Group A included 14 patients highly suspected of having an HCC which had previously been unsuccessfully biopsied. A transarterial embolization with lipiodol was performed in these patients to mark intrahepatic tumors which could not otherwise be defined in unenhanced CT. A biopsy was then repeated. Group B included 22 patients …

Erfassung hämodynamischer Parameter bei Patienten mit chronischer thromboembolischer pulmonaler Hypertonie mittels MRT vor und nach Thrombendarteriektomie

Purpose: To evaluate the potential of MRI to grade cardiac impairment and pulmonary hypertension in patients with chronic thromboembolic pulmonary hypertension (CTEPH) in comparison with invasive pressure measurements before and after surgery. Materials and Methods: We examined 35 patients with CTEPH before and after pulmonary thromboendarterectomy (PTE). For assessment of hemodynamics, velocity-encoded segmented GE-sequences (pulmonary arteries and ascending aorta) and segmented cine GE-sequences along the short axis of the heart were performed. The analysis comprised calculation of ejection fractions, peak velocities, mean pulmonary arterial flow and vessel diameter. 10 volunteers served …

Eine Kombination niedrig und hochauflösender dynamischer T1-gewichteter Sequenzen zur besseren Beurteilung der Morphologie Kontrastmittel aufnehmender Läsionen in der MRT der weiblichen Brust

Purpose: Presentation of a new protocol for simultaneous acquisition of both low and high resolution T 1 -weighted images of breast lesions for dynamic contrast-enhanced MR mammography. Demonstration of possible diagnostic improvement with representative measurements in patients with suspected breast cancer by adding morphologic parameters from high resolution sequences to the analysis of the signal-time curve. Materials and Methods: Dynamic MR imaging was performed with a 1.5 T system (Magnetom SONATA, Siemens Medical Systems, Germany) and the manufacturer's double-breast coil. Coronal T 1 -weighted 3D FLASH sequences (spatial resolution 1.25 ×1.25 mm 2 ; slice thickness 1.7 mm) were acqui…

Selbstorganisierende neuronale Netze zur automatischen Detektion und Klassifikation von Kontrast(mittel)-verstärkten Läsionen in der dynamischen MR-Mammographie

Purpose: Investigation and statistical evaluation of "Self-Organizing Maps," a special type of neural networks in the field of artificial intelligence, classifying contrast enhancing lesions in dynamic MR-mammography. Material and Methods: 176 investigations with proven histology after core biopsy or operation were randomly divided into two groups. Several Self-Organizing Maps were trained by investigations of the first group to detect and classify contrast enhancing lesions in dynamic MR-mammography. Each single pixel's signal/time curve of all patients within the second group was analyzed by the Self-Organizing Maps. The likelihood of malignancy was visualized by color overlays on the MR-…

Depiction of anomalous coronary vessels and their relation to the great arteries by magnetic resonance angiography

Three-dimensional respiratory-gated coronary MR angiography (MRA) allowed accurate analysis of the anatomy of the coronary arteries and their relation to the adjacent anatomic structures in two patients with anomalous origin and proximal course of the coronary vessels. Together with functional tests, it decisively influenced further therapy.

Undetected Malignancies of the Breast: Dynamic Contrast-enhanced MR Imaging at 1.0 T

To assess the prevalence and characteristics of malignant breast lesions not identified with magnetic resonance (MR) imaging.Breast tissue specimens were obtained in 464 of 967 patients who had undergone dynamic gadolinium-enhanced T1-weighted fast low-angle shot three-dimensional MR imaging of both breasts. A comparison of sensitivity, specificity, and predictive values of the prospectively recorded findings of mammography, ultrasonography (US), and MR imaging with the histopathologic results was performed with receiver operating characteristic (ROC) curve analysis. MR imaging examination findings that caused a false-negative diagnosis were reviewed to identify possible sources of error.Hi…

Die perkutane Harnleiterokklusion

One hundred and nineteen transrenal occlusions of 77 ureters were carried out in 71 patients. Thirty-one ureters were occluded by means of glue and in 21 Gianturco coils were introduced at the same time. Forty-six ureters were occluded by means of disposable silicone-filled latex balloons. Seventeen out of 31 ureters treated with glue (55%) and 32 out of 46 ureters with balloons (70%) were permanently occluded. On 42 occasions, re-occlusions had to be carried out, the average period from the initial occlusion being 2.5 weeks for glue and 19.5 weeks for balloons. In nine out of the 119 ureteric occlusions (7.5%), there were mild complications; these were easily treated and were of no consequ…

Endovaskuläre Behandlung akuter Erkrankungender thorakalen Aorta

Purpose To investigate the safety and efficacy of emergency treatment of acute aortic diseases with endovascular stent grafts. Methods In 11 patients (median age 55 years, range 18 - 85) with acute complications of descending aortic diseases endovascular emergency treatment was performed: traumatic aortic rupture (n = 4), penetrating ulcer with aortobronchial fistula or hematothorax (n = 4), acute type B dissection (n = 2, one with penetration, one with subacute mesenteric ischemia), and symptomatic aneurysm of the thoracic aorta (n = 1) with pain and diameter progression. 15 stent grafts were implanted (Talent n = 11, Vanguard/Stentor n = 4). Stent extension was necessary in 4 cases. In 2 …

Measurements of alveolar pO2 using 19F-MRI in partial liquid ventilation.

Rationale and Objectives: Partial liquid ventilation using Perfluorcarbon (PFC) is an innovative treatment of acute respiratory distress syndrome. However, the underlying mechanisms are not totally clear. The aim was to investigate the distribution of oxygen partial pressure within the PFC-filled lung (ppO 2 ). Methods: Nine pigs underwent partial liquid ventilation, receiving 20 mL PFC/kg bodyweight (bw). Measurements were obtained by a chemical shift selective TurboFLASH sequence at different axial lung levels. ppO 2 was calculated from 1 9 F-MRI by nonlinear curve T 1 -fitting technique after noise correction. Results: Quantification and distribution of ppO 2 was performed successfully. …

Intravaskuläre Sonographie: Erste klinische Ergebnisse

Intravascular ultrasound is a new diagnostic modality which, for the first time, provides high resolution images of the vessel wall. 91 intraluminal ultrasound studies were performed in 50 patients during the course of 55 diagnostic and therapeutic catheterizations. A F-6 ultrasound catheter (20 MHz) was used. The method is an easily and rapidly performed addition to angiography. Changes in vessel walls (arteriosclerosis, dissection, tumour infiltration) can be readily diagnosed and their extent can be accurately described. The ability to determine luminal cross sectional area is particularly helpful for planning and performing therapeutic interventions.

Automatische Berechnung des Milzvolumens aus Spiral-CT-Daten mit Hilfe neuronaler Netze und „Fuzzy Logik”∗

PURPOSE To assess spleen segmentation and volumentry in spiral CT scans with and without pathological changes of splenic tissue. METHODS The image analysis software HYBRIKON is based on region growing, self-organized neural nets, and fuzzy-anatomic rules. The neural nets were trained with spiral CT data from 10 patients, not used in the following evaluation on spiral CT scans from 19 patients. An experienced radiologist verified the results. The true positive and false positive areas were compared in terms to the areas marked by the radiologist. The results were compared with a standard thresholding method. RESULTS The neural nets achieved a higher accuracy than the thresholding method. Cor…

Temporal dynamics of lung aeration determined by dynamic CT in a porcine model of ARDS

We used dynamic CT to identify two different time constants of lung aeration and their individual contribution to the total increase in cross-sectional lung area in healthy and experimentally damaged lungs. In five healthy pigs, inflation and deflation between 0 and 50 cm H2O was imposed during dynamic (250 ms/image) CT acquisition, and repeated after experimental lung injury by saline lavage. The fractional areas of density ranges, which represent aerated lung parenchyma, were determined planimetrically, and their time for expansion during the manoeuvre was fitted using a bi-exponential model. Thus, two compartments, their sizes, i.e. their relative contributions to lung area aerated by th…

Magnetresonanztomographie (MRT) der Leber und des Gehirns bei hämatologisch-onkologischen Patienten mit Fieber unbekannter Ursache

PURPOSE To examine the advantage of liver and brain MRI in clinically anomalous haematological patients with fever of unknown origin. MATERIAL AND METHODS Twenty liver MRI (T2-TSE, T2-HASTE, T1-FLASH +/- Gd dynamic) and 16 brain MRI (T2-TSE, FLAIR, T1-TSE +/- Gd) were performed searching for a focus of fever with a suspected organ system. Comparison with clinical follow-up. RESULTS A focus was detected in 11/20 liver MRI. Candidiasis (n = 3), mycobacteriosis (n = 2), relapse of haematological disease (n = 3), graft versus host disease (n = 1), non-clarified (n02). The remaining 9 cases with normal MRI were not suspicious of infectious hepatic disease during follow-up. In brain MRI, 3/16 sho…

Möglichkeiten der 16-Schicht-CT bei der linksventrikulären Funktionsbestimmung: Beurteilung zweier unterschiedlicher Software-Tools zur quantitativen Funktionsanalyse sowie qualitative Bewertung von Wandbewegungsstörungen im Vergleich zur Magnetresonanztomographie

PURPOSE To determine global and regional left ventricular (LV) function from retrospectively gated multidetector row computed tomography (CT) by using two different semiautomated analysis tools and to correlate the results with those of magnetic resonance imaging (MRI). MATERIALS AND METHODS Nineteen patients (5 females, 14 males, mean age 69 years) underwent 16-slice spiral-CT (MS-CT) with standard technique without administration of beta-blockers for a decrease in the cardiac rate. Ten series of images were reconstructed at every 10 % of the RR-interval. With commercially available software capable of semiautomated contour detection, end-diastolic and end-systolic LV volumes (EDV and ESV)…

3D-CT von Frakturen: Vergleich von Volumen- und Oberflächen-Rekonstruktionen

Purpose The comparison of volume rendering (VR) and surface rendering (SSD) for demonstrating fractures from spiral-CT data. Materials and methods Standardized VR and SSD projections were produced from 50 spiral CT scans of 50 consecutive patients with fractures. Appropriate multiplanar reformattings (MPR) were used as the standard. Results SSD provided sufficient information in 31/50 cases. Results of VR were not significantly different (33/50). VR was superior in demonstrating 6/7 craniofacial fractures and 3/3 calcaneal fractures. SSD was superior for visualizing 2/3 shoulder fractures and 2/2 elbow fractures. Conclusion VR is a flexible technique for the depiction of fractures and the a…

Malignant peripheral neuroectodermal tumors in urology.

During the past few years, a new tumor type has emerged in the pediatric and adolescent group of cancer patients, which has been designated malignant peripheral neuroectodermal tumor (MPNT). This tumor has some clinical and pathological signs in common with either soft-tissue sarcomas or classic Ewing's sarcoma, but is defined as a distinct entity because of its immunohistological characteristics. The tumor expresses neuronal markers, but the pattern varies: chromogranin, neuron-specific enolase, synaptophysin, protein S-100 and others. MPNT can occur in the urogenital region. The differential diagnosis on clinical grounds must include Ewing's and soft tissue sarcomas, and also Wilms' tumor…

Die dynamische31Phosphor-Magnetresonanz-Spektroskopie des M. quadriceps: Therapiebedingte Veränderungen bei arterieller Verschlußkrankheit

PURPOSE: The present investigation aimed at examining changes in muscle metabolism caused by treatment of arterial occlusive disease, using dynamic 31-phosphorus methods. METHOD: 32 patients with arterial occlusive disease were examined in a 1.5 T apparatus with a 6 cm surface coil before and after treatment. The metabolic changes in the quadriceps muscles were visualised during a 36 s phosphorus spectrum during rest, exercise (isometric and isotonic) and during a period of recovery. RESULTS: Vascular therapy resulted in a significant increase in the duration of both types of exercise during dynamic phosphorus spectroscopy (isometric exercise: 282 s against 199 s: p = 0.002, isotonic exerci…

Kontrastmittelverstärkte dreidimensionale MR-Angiographie der Lungenarterien bei Patienten mit chronisch-rezidivierender Lungenembolie - Vergleich mit der selektiven intraarteriellen DSA∗ *

Purpose: This study compares contrast-enhanced 3D-MR angiography (MRA) of the pulmonary arteries with selective intraarterial DSA in patients with chronic thromboembolic pulmonary hypertension. Materials and Methods: 20 patients preoperatively underwent a contrast-enhanced 3D-MRA of the pulmonary arteries at 1.5T using the phased-array body coil. For MRA, we used a 3D-Flash-sequence after bolus timing. 2 radiologists analyzed the acquired image material in consensus with respect to the detection of central thromboembolic material and the visualization of the pulmonary arterial tree. Finally, the MR angiograms were compared with selective DSA images using surgical findings as the definitive …

Dreidimensionale Rekonstruktionen von computertomographischen Untersuchungen des knöchernen Schädels bei kraniofazialen Dysplasien und Frakturen

Eine Routineuntersuchung am CT gilt in der Regel nach Anfertigen der zweidimensionalen Querschnittbilder als beendet. Nahezu alle Computertomographen sind heute jedoch technisch dazu in der Lage, aus den Daten zweidimensionaler CT-Bilder ein dreidimensionales Oberflachenbild zu berechnen. Ein diagnostischer Nutzen dieser Sekundarrekonstruktionen wird oft angezweifelt, da im Vergleich zu den Querschnittbildern keine zusatzliche Information gewonnen werden kann [1, 3, 6, 15]. Unabhangig von dieser Tatsache zeigen jedoch diejenigen Chirurgen ein zunehmendes Interesse fur 3-D-Darstellungen, die in komplexen anatomischen Gebieten arbeiten und sich praoperativ eine optimale raumliche Vorstellung …

Ultraschnelle MRT der Lungenventilation mittels hochpolarisiertem Helium-3*

Objective Assessment of the temporal and spatial dynamics of hyperpolarized Helium-3 (3He) distribution in the lung with ultrafast gradient-echo magnetic-resonance imaging. Material and methods Coronal images of the lung were acquired using ultrafast gradient-echo pulse sequences with TR/TE = 3.3 ms/1.3 ms (slice thickness, 40 mm) and TR/TE = 2.0 ms/0.7 ms (without slice selection). A series of 80 or 160 projection images was obtained with 210 ms or 130 ms temporal resolution, respectively. Imaging was performed during several respiratory cycles after application of a single bolus of 300 mL hyperpolarized 3He. Measurements were performed in six healthy volunteers (spontaneous breathing). Re…

Detection of coronary artery calcifications predicting coronary heart disease: comparison of fluoroscopy and spiral CT.

The aim of this study was to evaluate the clinical relevance of coronary artery calcifications detected by spiral CT, congruence with fluoroscopy (FS) and coronary angiography, and comparison with studies reporting on application of double-helical CT and ultrafast CT. Forty patients underwent spiral CT (2-mm slice thickness, table feed 3 mm/s), coronary angiography, and FS (performed in the usual manner). Stenosis and calcifications were evaluated semiquantitatively. Nineteen patients suffering from a stenosis ≥ 75 % were verified at coronary angiography. All had coronary artery calcification on spiral CT. Fluoroscopy did not detect 8 of 19 patients with a stenosis ≥ 75 % (1 vessel: n = 1; …

Pneumomediastinum and pneumopericardium due to malignant subcarinal lymphadenopathy: CT demonstration

A 52-year-old man had been treated for oral cancer T3 N0 M0 by radical surgery, neck dissection on the right and cervical irradiation (60 Gy). Two months after therapy he presented with dysphagia and hemoptysis. Admission chest X-ray revealed a pneumopericardium. It was caused by a bronchomediastinal fistula due to necrotic metastatic lymph nodes as shown by CT, which also revealed a concomitant pneumomediastinum. The patient died 10 days later from pneumonia. The CT findings were confirmed at autopsy. We conclude that malignant mediastinal lymphadenopathy is a potential cause of pneumopericardium and pneumomediastinum.

Diagnostik der trachealen Instabilität: Spiral-CT in Inspiration und Exspiration und respiratorische cine-CT∗

ry Spiral CT and Cine CT. Purpose: In tracheo- and broncho-malacia, localization and determination of collapse is necessary for planning a surgical procedure. We compared inspiratory and spiral CT, cine CT, and bronchoscopy and evaluated the relevance of each method. Methods: Seventeen patients with suspected or verified tracheal stonosis or collapse underwent paired inspiratory and exspiratory spiral CT and cine CT during continuous respiration (temporal increment 100 ms). The tracheal cross-sectional area was calculated and compared. Results : In addition to bronchoscopy, further information concerning localization, extent, collapse, stability of the tracheal wall, distal portions of the …

Electromagnetically generated extracorporeal shock waves for gallstone lithotripsy: in vitro experiments and clinical relevance.

. First generation shock wave sources have been proved to disintegrate gallstones effectively, but they require the immersion of the patient's body in a tank of water. A recently developed second generation shock wave source (Siemens-Lithostar, Erlangen, FRG) generates shock waves electromagnetically. It presents several novel features. In particular the waterbath can be omitted and due to lower shock wave pressure general anaesthesia is not required. In vitro studies showed that 36 out of 38 gallstones (11–30 mm in diameter) could be disintegrated. Two concrements resisting lithotripsy were pure white cholesterol stones. Independent of shape, size, and composition (cholesterol or pigment) …

Bolus-enhanced renal spiral CT: technique, diagnostic value and drawbacks

Abstract In addition to pre- and postcontrast renal CT scans, early bolus-enhanced spiral scans during demarcation of the corticomedullary junction were acquired in 85 patients. The diagnostic value and drawbacks of the three imaging series in the evaluation of renal disease were assessed. Renal calcifications and calculus disease detected at precontrast scans (18%) were obscured after contrast administration and excretion in most cases. In the detection of renal lesions bolus-enhanced spiral CT and delayed postcontrast scans had an identical diagnostic yield (94%). Bolus-enhanced spiral CT was superior in the assessment of lesion vascularity and vascular anatomy as well as opacification of…

Review article: Percutaneous transhepatic biliary drainage: Experience with 311 procedures

Percutaneous biliary drainage was performed in 296 patients on 311 occasions using a fine-needle puncture technique. In 59%, the procedure served as postoperative decompression, and in 35% for palliation of obstruction, particularly in malignant disease. Postoperative drainage for the management of postoperative complication accounted for 2.5%. In more than 80% of the patients treated, the underlying disease was malignant obstructive jaundice. In 257 retrospectively evaluated patients the following complications were observed: cholangitis (6.6%), sepsis (3.1%), bile leakage (1.6%) with two deaths (0.7%), and subcapsular hematoma and hematoma in the hepatoduodenal ligament (1.2%). Catheter d…

Meßfehlerschätzung bei der MR-tomographischen Volumetrie des linken Ventrikels mit Mehrschicht-Technik

A multi-slice technique for MRT measurements of the left ventricular volume is much faster than the use of single-slice methods and is therefore better tolerated, leaving time for additional measurements. The end-diastolic left ventricular volume can be reliably measured by this method (123.3 +/- 13.5 ml vs. 124.1 +/- ml). The end-systolic volume is consistently overestimated by 23.7 +/- 18.3% compared with the reference value obtained by single slice measurements (47.9 +/- 8.9 ml vs 39.1 +/- 7.9 ml). Correspondingly, stroke volume and ejection fraction is underestimated on average by 10.6 +/- 9.7% and 10.6 +/- 7.6% respectively).

Die dynamische31Phosphor-Magnetresonanz-Spektroskopie des M. quadriceps: Metabolische Veränderungen unter zwei verschiedenen Belastungsformen

PURPOSE The aim of the present investigation was to examine the metabolism of the quadriceps muscles of normal young individuals using dynamic 31phosphorus magnetic resonance spectroscopy. METHODS 22 normal individuals were examined in a 1.5T-MRT using a 6 cm surface coil. The metabolic changes in the quadriceps muscle as shown by the phosphorus spectrum were evaluated during rest, exercise (isometric and isotonic exercise) and during a 36-second period of recovery. RESULTS The Pi/PCr quotient rose from its resting value of 0.11 +/- 0.02 following exercise to a maximum of 0.83 +/- 0.47 (isometric) or 1.40 +/- 0.59 (isotonic) (difference p = 0.0001). Half-time recovery of Pi/PCr was 35 +/- 1…

Diagnose eines intramyokardialen Hämatoms nach traumatischem Myokardinfarkt durch Magnetresonanztomographie

Thoraxverletzungen treten bei etwa 30% aller traumatisierten Patienten auf, wobei in den meisten Fallen Verkehrsunfalle die Ursache sind. Wir berichten uber den Fall eines Patienten, der nach einem Skiunfall einen traumatischen Vorderwandinfarkt erlitt. Im weiteren Verlauf kam es zu einer ausgedehnten intramyokardialen Einblutung. Differentialdiagnostisch kam zunachst ein linksventrikulares Pseudo- bzw. Pseudopseudoaneurysma in Frage, kernspintomographisch konnte jedoch durch den Nachweis eines schmalen Myokardsaums sowohl ventral als auch dorsal der Raumforderung die Diagnose eines intramyokardialen Hamatoms gestellt werden. Bei dem Patienten wurde daraufhin eine aortokoronare Bypass-Opera…

Therapie des Koronar-steal-Syndroms mittels perkutaner transluminaler Angioplastie

Superior labrum and labral-bicipital complex: MR imaging with pathologic-anatomic and histologic correlation.

The purpose of this study was to analyze the anatomic relationship between the superior labrum, the superior glenoid rim, the superior glenohumeral ligament, and the long head of the biceps tendon.Seventeen cadaveric shoulder specimens underwent axial, oblique coronal, and oblique sagittal MR imaging on a 1.5-T imager. Unenhanced proton density- and T2-weighted spin-echo images with and without fat suppression, and T1-weighted fat-suppressed spin-echo images after intraarticular injection of gadolinium, were obtained of each specimen. The shoulders were then frozen and sectioned into 4-mm-thick slices, either transversely or oblique coronally. After gross anatomic correlation, histologic an…

MR-Tomographie bei Innenbandverletzungen des Kniegelenkes

Frequency and characteristics of lesions of the medial collateral ligaments (MCL) were studied by MRI in 155 patients with trauma to the knee. There were abnormalities of the MCL in 38% of cases with ligamentous injuries and in 27% these were combined with meniscal tears. 11% of these patients showed isolated rupture of MCL and as a result of the MRI findings were treated conservatively. By means of T2*-weighted images the individual lesions could be accurately localised. Characteristic findings have been defined.

Akute oder chronische Transplantat-Abstoßung? - HRCT des Thorax bei Patienten nach Lungentransplantation

Purpose: Aim of the study was to evaluate the postoperative changes in patients with single (SLTX) or double lung transplantation (DLTX) with HRCT and to correlate those findings with the clinical diagnosis. Material and methods: 29 patients with SLTX (n = 14) or DLTX (n=15) were observed for more than 6 years after transplantation by HRCT (n =82). CT examinations were performed in inspiration and expiration (n=70) with a slice thickness of 1 mm and a feed of 10 mm. The image material was evaluated by 2 experienced radiologists in consensus. Criteria for acute rejection at HRCT were: ground glass opacities and focal air trapping in expiration. Criteria for chronic transplant rejection were:…

Quantitative Bestimmung der Hirnperfusion mit Hilfe der digitalen Subtraktionsangiographie (DSA)

In a search for a reliable and relatively non-invasive method for quantifying cerebral perfusion, we examined the possible role of DSA. By using special software, it is possible to demonstrate vascular morphology and obtain functional data concerning blood flow. Regions of interest are used for obtaining time-density curves and these are evaluated by a formula designed by Meier and Zierler. Perfusion through the arterial territory in both cerebral hemispheres was correlated with the clinical symptoms of the patients and with the morphological findings. Difficulties and problems are described and discussed.

Dynamic computed tomography: a novel technique to study lung aeration and atelectasis formation during experimental CPR

Objective: To develop an image based technique to study the effect of different ventilatory strategies on lung ventilation and alveolar recruitment during cardiopulmonary resuscitation (CPR). Design: (1) Technical development of the following components: (a) construction of an external chest compression device, which does not interfere with CT imaging, and (b) development of a software tool to detect lung parenchyma automatically and to calculate radiological density parameters. (2) Feasibility studies: three strategies of CPR ventilation were performed and imaged in one animal each (pigs, 25 kg): volume-constant ventilation (VCV), no ventilation, or continuous airway pressure (CPAP). One m…

Anthrazyklin-induzierte Kardiotoxizität: MRT des Herzens bei Kindern und Jugendlichen mit malignen Erkrankungen

Purpose: Quantification of left and right ventricular function using MRI in young cancer patients treated with cardiotoxic anthracyclines. Materials and Methods: Twenty-eight patients (mean age 16.4 years) underwent cardiac MRI at 1.5 T. The study protocol consisted of morphologic T2-weighted images with fat suppression and cine steady-state free precession sequences (SSFP) for functional analysis. Seven patients were examined at the end of chemotherapy, two of them also repeatedly during therapy, and 21 patients following an average period of three years after finishing chemotherapy (range one month - 20 years) Results: The end-systolic volume index increased and the ejection fraction of t…

Magnetresonanztomographie des Kniegelenks mit einem Niederfeldsystem

Ziel der vorliegenden Untersuchung ist die Evaluierung der Niederfeldmagnetresonanztomographie an einem offenen System unter Berucksichtigung des Erfahrungsstands des Untersuchers. In einer prospektiven Studie wurden von August 1995 bis Mai 1997 75 Patienten der Klinik fur Unfallchirurgie der Universitat Mainz mit einem akuten Trauma des Kniegelenks nach klinischer und konventionell-radiologischer Diagnostik magnetresonanztomographisch untersucht und anschliesend diagnostisch und therapeutisch arthroskopiert. Die Auswertung der MRT-Untersuchungen erfolgte hierbei durch 2 unabhangige Untersucher unterschiedlichen Erfahrungsstands ohne Kenntnis der Anamnese bzw. des klinischen Befunds. Sensit…

Injuries of the lateral collateral ligaments of the ankle: assessment with MR imaging.

The aim of this study was to evaluate the ability of MRI to display injuries of the lateral collateral ligamentous complex in patients with an acute ankle distorsion trauma. The MR examinations of 36 patients with ankle pain after ankle distorsion were evaluated retrospectively without knowledge of clinical history, outcome and/or operative findings. The examinations were performed on a 1. 5-T whole-body imager using a flexible surface coil. The signs for ligamentous abnormality were as follows: complete or partial discontinuity, increased signal within, and irregularity and waviness of the ligament. The results were compared with operative findings in 18 patients with subsequent surgical r…

Experimentelle In-vitro-Studie zur Evaluierung eines elektronischen Detektors für die digitale Radiographie

Purpose: To evaluate the contrast-detail performance of a flat-panel detector system, we performed a comparative study of this flat-panel system versus storage phosphor and conventional screen-film systems. Materials and Methods: Bone models made of human humeri were prepared with foreign bodies, fracture lines and drilled holes to create artificial fractures, osteolyses or metastases. Immersed in a water bath, hard copy images of these models were acquired with the same exposure dose (55 kV; 3.2 mAs) on the flat-panel detector, two state-of-the-art storage phosphor systems (PCR®, ADC®) and two conventional screen-film systems (Insight®, T-Mat®). Using a standardized protocol with a 4-point…

Kontrastverstärkte dreidimensionale MR-Angiographie der A. carotis bei 1,0 Tesla im Vergleich zuri.a. DSA - ist die Methode für die Diagnostik von Karotisstenosen geeignet?

Artery Disease? Purpose: To evaluate the efficacy of three-dimensional, contrast-enhanced magnetic resonance angiography (CE-MRA) of the carotid artery with a 1.0 system in comparison to intra-arterial conventional angiography (i.a.CA) for the assessment of carotid artery disease. Method: 55 patients with suspected stenosis of the carotid artery were examined with a 3D-CE gradient-echo sequence on a 1.0 T scanner (TR/TE = 6.2/2.2 ms) and a selective DSA i.a. angiography. Image quality was evaluated by estimating the arterial contrast and venous enhancement. Morphological pathologies were registered for all arteries, stenoses of the internal carotid artery were graded by applying the NASCET …

Computerunterstützte Diagnostik in der Thoraxradiologie - aktuelle Schwerpunkte und Techniken

The proliferation of digital data sets and the increasing amount of images, e. g. through the use of multislice spiral CT or multiple follow-up examinations in the context of new therapies, are ideal prerequisites for computer-aided diagnosis (CAD) in chest radiology. Multiple studies have described the applications and advantages of computer assistance in performing different diagnostic tasks. More powerful computers will enable the introduction of these systems into the clinical routine and could provide an enormous increase in morphological and functional information. The commercial introduction of tools for detection and visualization of pulmonary nodules has already begun. This is one …

Ganzkörper-Spiral-CT zur Primärdiagnostik polytraumatisierter Patienten unter Notfallbedingungen

PURPOSE The aim of this study was to evaluate the role of a fast whole body helical CT scanner for primary diagnosis in trauma patients. METHODS 27 severely injured patients (9 women, 18 men; mean age 43 years) were first examined with a helical CT scanner allowing for digital radiograms up to a length of 1024 mm and continuous helical scans of up to 70 seconds (slice thickness 3 to 10 mm, pitch factor up to 2). The primary CT diagnosis was verified either by x-ray after the CT examination or during the subsequent days, by abdominal ultrasound, by additional CT scans in the following days, and by clinical follow-up. RESULTS CT showed all clinically relevant injuries of the head, spine, ches…

Normal and abnormal pulmonary ventilation: visualization at hyperpolarized He-3 MR imaging.

To assess the feasibility of helium-3 magnetic resonance (MR) imaging with a three-dimensional fast low-angle shot (FLASH) sequence, He-3 gas (volume, 300 mL; pressure, 3 x 10(5) Pa; polarized up to 45% by means of optimal pumping) was inhaled by five healthy volunteers and five patients with pulmonary diseases. All breath-hold examinations (22-42 seconds) were completed successfully. Normal ventilation was depicted with homogeneous high signal intensity, lesions were depicted as causing defects, and obstructive lung disease was depicted with severely inhomogeneous signal intensity.

Systematische Analyse der Geometrie eines definierten Kontrastmittelbolus - Implikationen für die kontrastmittelverstärkte 3D-MR-Angiographie thorakaler Gefäße

Purpose: Little is known about the dispersion of a defined contrast bolus during its passage through the heart and pulmonary vasculature. The purpose of this study was to analyze factors influencing a defined contrast bolus for ce-MRA of thoracic vessels. Materials and Methods: For analysis of bolus geometry, an ECG-gated saturation-recovery Turbo-Flash sequence with a TI of 20 msec was used. It was acquired axially at the level of the pulmonary trunc, so that with one data acquisition a curve analysis was possible in the ascending and descending aorta, and in the pulmonary trunc. Twenty-nine patients received 3 ml of Gd-DTPA diluted with saline to a total of 20 ml. Contrast injection was d…

Drei-Phasen-Spiral-CT in der Diagnostik von Lebererkrankungen: Vergleich mit CT-Arteriographie und -Arterioportographie

PURPOSE Assessment of the diagnostic efficacy of triphasic spiral-CT scanning (TPS-CT) for liver disease evaluation. CT arteriography (CTA) and CT arterio-portography (CTAP) were used as reference, methods which together have the highest sensitivity for detecting tumours and the perfusion conditions of the liver. MATERIAL AND METHODS 50 TPS-CT and CTA/CTPA were performed in 49 patients. After an initial examination without enhancement the first scan was initiated 15-25s after the peripheral bolus injection of contrast medium, the second after an interscan delay of 20-25s. By this means the liver was imaged in different phases of perfusion. In the course of the CTA/CTPA-exam the imaging was …

Prä- und postoperative Evaluation von linksventrikulären Herzspitzenaneurysmen mittels Cine-MRT

Purpose: To demonstrate the usefulness of cine-MRI for the evaluation of apical left ventricular aneurysms (ALVA) and for prediction of the surgical outcome. Materials and Methods: We investigated 28 patients with ALVA, 13 of them additionally after aneurysmectomy at 1.5 T; 15 healthy volunteers served as normal controls. For cine-MRI k-space segmented FI-2D-GE sequences were used. Analysis comprised the calculation of cardiac volume indices, cardiac function, and percentual myocardial thickening (PMT). For prediction of surgical results we divided left ventricle into an aneurysmatic and a non-aneurysmatic part. The non-aneurysmatic part was assumed as the left ventricle after surgical remo…

Pulmonary balloon angioplasty of chronic thromboembolic pulmonary hypertension (CTEPH) in surgically inaccessible cases.

Abstract The clinical course of patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH) depends on the distribution pattern of the thromboembolic material. In patients with thromboembolic findings in the central pulmonary segments pulmonary thrombendarterectomy (PTE) has excellent results and acceptable operative risk. This paper presents two surgically inaccessible cases that were successfully treated with balloon pulmonary angioplasty. Balloon angioplasty improved parenchymal perfusion, increased cardiac index (Delta CI +19.2 % [Case 1], and +15.4 % [2]), reduced pulmonary vascular resistance during follow-up (Delta PVRI -25.0 % [1] and -15.9 % [2]), and is discussed…

Value of routine abdominal and lymph node sonography in the follow-up of breast cancer patients.

Abstract Objective: The aim of this study was to review usefulness and intervals for abdominal sonography during the follow-up of breast cancer patients. Additionally, we assessed the value of regional lymph node sonography in patients with possible locoregional recurrence. Subjects: Retrospectively, 2657 abdominal ultrasound examinations of 414 patients and 299 sonographic examinations of the regional lymph nodes in 227 patients after surgical treatment for breast cancer were evaluated. Results: Follow-up abdominal sonography revealed metastases in 6.8% of patients, and in 1% of examinations. There was no dependence on the initial T- or N-stage. At sonography of the regional lymph nodes in…

Kryotherapie maligner Tumoren: Untersuchungen mittels MRT im Tierexperiment und Vergleich mit morphologischen Veränderungen*

son with pathological changes in mice. Purpose: Aim of our study was to investigate the efficacy of 7 F cryoprobes for percutaneous use morpho- and histologically, to examine the role of apoptosis after cryotherapy, and to compare contrast-enhanced MRI with histopathological findings at different time intervals in a tumor-mouse model. Methods: Percutaneous cryotherapy was performed in 15 immunocompromised nude mice with subcutaneously implanted tumors using the non-small-cell lung cancer cell line Lu 1. In group a) 7 mice were sacrificed after definite time intervals and histological examinations were done for evaluation of necrosis and apoptosis (HE; TUNEL assay); 2 mice are in long-term f…

CT-guided intratumoral gene therapy in non-small-cell lung cancer.

The objective of this study was to prove the principle of CT-guided gene therapy by intratumoral injection of a tumor suppressor gene as an alternative treatment approach of incurable non-small-cell lung cancer. In a prospective clinical phase I trial six patients with non-small-cell lung cancer and a mutation of the tumor suppressor gene p53 were treated by CT-guided intratumoral gene therapy. Ten milliliters of a vector solution (replication-defective adenovirus with complete wild-type p53 cDNA) were injected under CT guidance. In four cases the vector solution was completely applied to the tumor center, whereas in two cases 2 ml aliquots were injected into different tumor areas. For the …

Chronische thromboembolische pulmonale Hypertonie: Diagnostische Wertigkeit von Mehrschicht-CT und selektiver Pulmonalis-DSA

Purpose To evaluate the diagnostic impact of multislice-CT and selective pulmonary DSA in chronic thromboembolic pulmonary hypertension (CTEPH). Methods 994 vessel segments of 14 consecutive patients with CTEPH were investigated with multislice-CT (slice thickness 3 mm, collimation 2.5 mm, reconstruction intervall 2 mm) and selective pulmonary DSA (posterior-anterior, 45 degrees oblique, and lateral projection. Analysis was performed by 2 investigators independently for CT and DSA. Diagnostic criteria were occlusions and non-occlusive changes like webs and bands, irregularities of the vessel wall, diameter reduction and thromboembolic depositions at different levels from central pulmonary a…

Rationelle bildgebende Diagnostik von Becken- und Azetabulum- verletzungen

In spite of the widespread availability of CT scanners, conventional X-ray radiographs remain the basic imaging modality in patients with pelvic and/or acetabular trauma. However, the extent of their use will depend on local utilities (e.g., availability of CT scanners) and on the patient's clinical condition. Regarding the inaccuracy of conventional radiography in the diagnosis of injuries of the dorsal pelvic ring and of the acetabulum, computed tomography represents the most important imaging modality in the clinically stable patient. CT provides an exact staging of the extent of trauma and allows for differentiation of pelvic instabilities. CT clearly demonstrates the severity of acetab…

Kontrastmittelverstärkte 3D-MRA der Pulmonalarterien mit integrierter paralleler Akquisitionstechnik (iPAT) bei Patienten mit CTEPH - sagittale oder koronare Datenaufnahme?

PURPOSE Comparison of two different types of contrast-enhanced 3D-MR angiography (CE-MRA) with integrated parallel acquisition technique (iPAT) in patients with chronic-thromboembolic pulmonary hypertension (CTEPH) and evaluation whether sagittal acquisition with higher resolution and minimized acquisition time is superior to common coronal orientation. MATERIALS AND METHODS CE-MRA was performed on 15 patients with CTEPH preoperatively and on 10 patients also postoperatively, while 5 other patients received only a postoperative MRA. All 30 MR studies with one coronal and two sagittal acquisitions were blindly evaluated and compared. The resolution of coronal and sagittal MRA was 1.3 x 0.6 x…

Diagnostik der akuten Lungenembolie mittels Spiral-CT und 3D-Rekonstruktion

Ziel: Die Entwicklung von Modellen zur Evaluierung der Spiral-CT und 3D-Rekonstruktion im Nachweis der akuten Lungenembolie (LE) im Ex-vivo-Experiment. Material und Methoden: Standardisierte kunstliche Emboli definierter Grose und Geometrie wurden in Schweinelungen eingebracht. Ausgusse der embolisierten Gefasbaume mit rontgenkontrastgebendem Kunstharz simulierten das CT-morphologische Vollbild einer Lungenembolie. Die Bilddaten wurden dreidimensional rekonstruiert und die Exaktheit der detektierten Emboluslokalisation durch Korrelation mit dem Originalpraparat verifiziert. Messungen an technischen Probekorpern mit eingeschlossenen Emboli definierter Grose sollten die Messgenauigkeit der ko…

Tissue characterization of benign brain tumors: Use of NMR-tissue parameters

Abstract To evaluate the potentials of NMR tissue parameters for tissue characterization we investigated 68 patients with benign brain tumors. Tissue parameters were accurately measured by a recently developed interlaced triple sequence. Each individual tumor was characterized by a set of three numbers (relaxation times T 1 and T 2 and proton density Rho). Different tumors exhibited significant overlaps of the three tissue parameters. Therefore a reliable prediction of the histological diagnosis based on the quantitative analysis of tissue parameters alone was not possible. T 2 -prolongation correlated well with water content and “regressive changes” in meningiomas and neuromas.

Endovaskuläre Aneurysmatherapie - Langzeitergebnisse nach 7 Jahren

Hintergrund: Seit der Entwicklung von Stentprothesen und deren kommerzieller Verfugbarkeit 1994 gibt es eine neue, sich zunehmend verbreitende endovaskulare Methode der Aneurysmatherapie.

Assessment of chronic aortic dissection: contribution of different ECG-gated breath-hold MRI techniques.

Our objective was to evaluate the impact of different rapid MRI techniques for the assessment and follow-up of chronic aortic dissections.Fifty-three patients (41 postoperative Stanford type A, 12 type B dissections) were scanned at 1.5 T during a 3-year period. The study reviewed ECG-gated breath-hold black blood sequences and 3D contrast-enhanced MR angiography of the thoracic aorta supplemented by segmented cine and phase-contrast imaging as well as abdominal contrast-enhanced MR angiography. A retrospective separate analysis of black blood acquisitions and contrast-enhanced MR angiograms from a total of 72 examinations was performed by two radiologists to evaluate detection of intimal f…

Nachsorge des Mammakarzinoms

7865 follow-up examinations were performed on 420 patients who had had surgery for carcinoma of the breast; there were 2755 radiographs of the chest, 2660 sonographic examinations of the upper abdomen and 2450 contralateral mammograms. The most common findings were metastases seen on the chest radiographs during the 13-24 and 25-60 months intervals in 4.7% of cases. The incidence increased with initially higher tumour stages and in ductal carcinomas. Sonography of the upper abdomen showed 4.3% of liver involvement, mostly between the second and fifth year; this was independent of tumour stage or the histology of the primary tumour. Positive mammography of the contralateral breast was found …

Visuelle Abschätzung der funktionellen Lungenanteile in der HRCT und 3He-MRT bei Patienten nach Einzel-Lungentransplantation: Vergleich mit der absoluten Volumetrie

Purpose: Visual assessment of the ventilation using HRCT and 3 He-MRI in patients after single lung transplantation (SLTX). Analysis of specific ventilation defects found with 3 He-MRI and morphological changes found with HRCT. Materials and Methods: We evaluated 8male patients (54 ′ 6 years) suffering from emphysema and six patients (3males and 3 females, 58 ′ 9.5 years) suffering from idiopathic pulmonary fibrosis (IPF) after SLTX. The morphological changes at HRCT were classified and localized. In 3 He-MRI (2D FLASH), 10 to 14 slices (slice thickness 10 mm, gap 5 mm) were acquired in coronal orientation to cover the whole lung. Ventilation defects were localized and characterized. The vi…

MRT des Herzens bei Verdacht auf Myokarditis

Purpose To evaluate the potential of ECG-gated breath-hold MRI in diagnosing acute myocarditis. Material and methods Cardiac MRI was performed on 21 consecutive patients with suspected myocarditis. ECG-gated breath-hold T2-weighted images with fat suppression were acquired in 3 standard views. T1-weighted imaging (FLASH) was performed 10 min after IV administration of Gd-DTPA. Laboratory data included creatine kinase, troponin T and serological tests, ECG findings and echocardiography. Imaging findings were retrospectively compared to the discharge diagnoses. Signal alterations were semiquantitatively classified. Results Acute myocarditis was diagnosed in 9 patients and cardiac sarcoidosis …

Nuclear magnetic resonance imaging with hyperpolarised helium-3

Abstract Summary Background Magnetic resonance imaging (MRI) relies on magnetisation of hydrogen nuclei (protons) of water molecules in tissue as source of the signal. This technique has been valuable for studying tissues that contain significant amounts of water, but biological settings with low proton content, notably the lungs, are difficult to image. We report use of spin-polarised helium-3 for lung MRI. Methods A volunteer inhaled hyperpolarised 3 He to fill the lungs, which were imaged with a conventional MRI detector assembly. The nuclear spin polarisation of helium, and other noble gases, can be greatly enhanced by laser optical pumping and is about 10 5 times larger than the polari…

Malignes fibröses Histiozytom

Malignant fibrous histiozytoma (MHF) is a pleomorphic sarcoma of ubiquituous origin. The clinical and radiological features of the tumor are illustrated by 23 patients with MFH of soft tissue and 4 MFH of bone. On conventional radiography MFH appears as a soft tissue tumor, sometimes with bone involvement; on sonography it is usually non-homogeneous and hypoechogenic with areas of necrosis. On CT the masses are homogeneous or inhomogeneous (10-60 HU.) containing areas of decreased density. Contrast enhancement was about 10-20 HU. Angiographically the tumor appears as hypo- or hypervascular with pathologic vessels. The morphology of MFH in diagnostic imaging including magnetic resonance tomo…

3He MRI in healthy volunteers: preliminary correlation with smoking history and lung volumes

MRI with hyperpolarized helium-3 (3He) provides high-resolution imaging of ventilated airspaces. The first aim of this 3He-study was to compare observations of localized signal defects in healthy smokers and non-smokers. A second aim was to describe relationships between parameters of lung function, volume of inspired 3He and signal-to-noise ratio. With Ethics Committee approval and informed consent, 12 healthy volunteers (seven smokers and five non-smokers) were studied. Imaging was performed in a 1.5 T scanner using a two-dimensional FLASH sequence at 30V transmitter amplitude (TR/TE/α = 11 ms/4.2 ms/<10°). Known amounts of 3He were inhaled from a microprocessor-controlled delivery device…

In-witro-NMR-Spektroskopie an gesunden, mastopathisch veränderten und karzinomatös befallenen Brustdrüsen-gewebsproben, korreliert mit histologischen Befunden

Es wurden bei 57 Patientinnen mit klinischem Verdacht auf Mammakarzinom 121 Gewebeproben entnommen und mittels der 1H-NMR-Spektroskopie bei 300 MHz in vitro nach Korrelation mit histologischen Befunden untersucht. Im interessanten Spektralbereich zwischen 2,7 und 4,1 ppm wurden starke Signale beobachtet, die Fett, (Phosphoryl-)Cholin, Kreatin(-phosphat) sowie Karnitin zugeordnet wurden. Weiterhin konnten mit hoher Regelmasigkeit 8 schwachere, zum Teil uberlappende Signale der Substanzen Glukose, Glyzin, Threonin, Serin, Inositol und Saccharose nachgewiesen werden. Hierbei wurden Linienintensitaten uber ein iteratives Fitprogramm bestimmt. Uber deren Quotienten konnten unterschiedliche Geweb…

Update on diagnostic strategies of pulmonary embolism

Acute pulmonary embolism is a frequent disease with non-specific findings, high mortality, and multiple therapeutic options. A definitive diagnosis must be established by accurate, non-invasive, easily performed, cost-effective, and widely available imaging modalities. Conventional diagnostic strategies have relied on ventilation-perfusion scintigraphy complemented by venous imaging. If the results are inconclusive, pulmonary angiography, which is regarded as the gold standard, is to be performed. Recently, marked improvements in CT and MRI and shortcomings of scintigraphy led to an update of the diagnostic strategy. Spiral CT is successfully employed as a second-line procedure to clarify i…

MRI-assisted radiation therapy planning of brain tumors--clinical experiences in 17 patients.

A new and simple method for precise determination of lateral opposed treatment portals was developed and used in 17 patients. Compared to CT, MRI led to significant changes of portals in 59% (10/17) of cases. Individual shielding blocks could be precisely designed by use of our new method. MRI is the procedure of choice in local radiation therapy planning of brain tumors.

Multirotations-CT während kontinuierlicher Beatmung: Vergleich unterschiedlicher Dichtebereiche bei gesunden Lungen und im Lavage-ARDS Modell

PURPOSE In this animal study, density ranges for CT-based quantification of ventilated lung area were determined. Healthy lungs and ARDS lungs were compared during artificial respiration. MATERIAL AND METHODS CT-scans were performed in 5 anesthetized pigs using a dynamic multiscan CT option on a predefined transverse slice (slice thickness 1 mm; effective temporal resolution, 250 ms). During continuous CT acquisition, airway pressure was increased or decreased in a stepwise manner. In all images, areas of defined HU ranges were determined planimetrically. The lower threshold was set to -910 HE in all images. The upper threshold was varied from -800 HE to -200 HE in steps of 100 HE. RESULTS …

Radiodiagnostik der Lunge

Die radiologischen Schnittbildverfahren, insbesondere die CT, haben sich innerhalb kurzer Zeit einen herausragenden Stellenwert in der Diagnostik von Lungenerkrankungen erworben. Dies umfasst in erster Linie die morphologische Darstellung pathologischer Prozesse mit hoher raumlicher Auflosung. Moderne technische Entwicklungen und kombinierte Untersuchungsstrategien eroffnen neue Einsatzgebiete und auch funktionelle Aussagen, die nach einer aktuellen Standortbestimmung gemeinsam mit den nuklearmedizinischen Verfahren verlangen. Dazu gehort die Diagnostik der Lungenembolie mittels Spiral-CT-Angiographie und MR-Angiographie der Pulmonalarterien. Hier hat sich mittlerweile die CT als alternativ…

Gadolinium-DTPA (Magnevist®) als Kontrastmittel für die Galaktographie

Analysis of intrapulmonary O2concentration by MR imaging of inhaled hyperpolarized helium-3

Inhalation of hyperpolarized 3He allows magnetic resonance imaging (MRI) of ventilated airspaces.3He hyperpolarization decays more rapidly when interacting with paramagnetic O2. We describe a method for in vivo determination of intrapulmonary O2 concentrations ([O2]) based on MRI analysis of the fate of measured amounts of inhaled hyperpolarized3He in imaged regions of the lung. Anesthetized pigs underwent controlled normoventilation in a 1.5-T MRI unit. The inspired O2 fraction was varied to achieve different end-tidal [O2] fractions ([Formula: see text]). With the use of a specifically designed applicator,3He (100 ml, 35–45% polarized) was administered at a predefined time within single …

Radiologische Diagnostik bei Dysphagie und Motilitätsstörungen des Ösophagus

Auswirkungen der Sauerstoffinhalation auf die Hämodynamik bei chronischer thromboembolischer pulmonaler Hypertonie

PURPOSE This study evaluates the haemodynamic effects of oxygen inhalation on pulmonary artery pressure and pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension. METHOD In 47 patients with chronic thromboembolic pulmonary hypertension haemodynamic parameters were measured before and after oxygen inhalation. RESULTS In moderately severe and severe pulmonary hypertension oxygen inhalation significantly reduced mean pulmonary artery pressure by about 11.1% and 4.6%, respectively. However, pulmonary vascular resistance was not significantly affected. Oxygen saturation improved and heart rate was reduced. Cardiac index decreased in severe pulmonary hyperte…

Magnetresonanztomographie bei chronischer Aortendissektion

17 patients with chronic aortic dissection were examined by MRI. In 12 patients, comparison between gradient echo sequences and SE sequences was possible. Gradient echo sequences, unlike SE sequences, permitted evaluation of flow in the true and false lumen, reliable differentiation between thrombus and flowing blood and clear delineation of the intimal flap. An additional comparison between transoesophageal ultrasound and MRT in 15 patients showed significant advantages in favour of MRI. In three patients MRI was able to detect more proximal origins of the dissection. Moreover, MRI allowed evaluation of the major aortic branches and their relation to the dissection; this was not possible w…

Angiographien im Kleinkindes- und Kindesalter

Between 1973 and 1991 we performed 160 percutaneous angiograms (130 arteriograms, 30 phlebograms) in children and infants; 12 patients were less than one year and 52 less than ten years old. 44 of the examinations were done by a DSA technique. The examinations were carried out under general anaesthesia except in 8 cases. In 50.7% an arteriogram was carried out for the investigation of a suspected or known tumour, in 9.3% an arteriogram was required following trauma. The most common phlebographic examination was for the demonstration of the spermatic vein; in 27 patients this was done for cryptorchidism or a varicocele. The only complication following a diagnostic angiogram was perforation o…

Gegenwärtiger Stellenwert der perkutanentranshepatischen Cholangiodrainage

Percutaneous transhepatic biliary drainage (PTBD) is a well established method in the treatment of obstructive jaundice. Major indications are malignant diseases. PTBD may be necessary preoperatively in cases with severe jaundice or cholangitis or as part of palliative treatment concepts. In the past, it has been proposed that a period of preoperative PTBD may improve the morbidity rates of surgery. Various studies could not prove this theory. The significance of preoperative PTBD has changed, as observed during a 15 years period in our own institution, the indications for preoperative PTBD have decreased by half. At present, the majority of treatments with PTBD are palliative (almost 70 % …

Endovaskuläre Therapie aortaler Aneurysmen: erste klinische Ergebnisse

PURPOSE A clinical study aiming at examining the implantation technique and the clinical results of a new vascular prosthesis in endovascular therapy of aneurysms of the aorta. MATERIAL AND METHODS In 21 patients (20 men of 55 to 87 years of age, average age 70 years) with aneurysms of the infrarenal abdominal aorta (AAA n = 19) and the thoracic aorta (n = 2), a self-expanding nitinol stent with outer Dacron sheath (tubular prosthesis n = 4; bifurcation prosthesis n = 17) was implanted by means of an F-18 introductory set after surgical opening of the inguinal artery. RESULTS By means of the 4 tubular prostheses and 13 of the 17 bifurcation prostheses the aneurysm was bypassed completely. I…

Three-dimensional helical CT of the tracheobronchial tree: evaluation of imaging protocols and assessment of suspected stenoses with bronchoscopic correlation.

To assess the accuracy of three-dimensional (3D) helical CT of normal airways, we evaluated different imaging protocols in test objects and patients. The clinical value of 3D helical CT was composed with bronchoscopy in patients with suspected stenoses, especially before and after endobronchial procedures.Solid test objects--one of central airways and one of peripheral airways--were scanned and assessed for volume defects and stairstep artifacts. Fifty helical studies were performed in 36 patients. We evaluated these images for visualization of segmental bronchi; frequency of artifacts; and presence, localization, and degree of stenoses. Bronchoscopic correlation was available for 40 CT exa…

Halslymphknotenmetastasen: Histologisch kontrollierter Vergleich von Palpation, Sonographie und Computertomographie

Sonography and CT were used pre-operatively for lymph node staging in patients with head and neck malignancies. The accuracy of the imaging methods surpassed that of palpation (palpation 85%, CT 85%, sonography 90%). Sensitivity was significantly increased from 74% (palpation) to 84% (CT) and 90% (sonography), ie. there was a reduction in false negative findings. Size of lymph nodes was not closely correlated with metastatic involvement. Reactively enlarged lymph nodes were more easily defined by CT and sonography than by palpation. This reduced the specificity of sonography (90%) and of CT (86%) compared to palpation (94%).

[CT-angiography in carotid stenosis].

Purpose: Prospective evaluation of the accuracy of CT angiography (CTA) with different postprocessing for extracranial carotid artery in comparison with DSA. Method: one hundred patients were studied with standarized CTA. For postprocessing, MPR, MIP, and 3D reconstruction based on segmentation with upper and lower threshold were used. Intravascular density profiles were considered. All CTA studies were correlated with intra-arterial angiography. The degree and classification of stenoses was determined using the guidelines established by the NASCET collaborators. Results: Measurement of stenosis was possible by MPR in 82.5 %, by MIP in 85 %, and 3D in 100 %. Correct classification was found…

Klinische Relevanz der NNH-CT vor Knochenmarktransplantation

PURPOSE To investigate the clinical necessity of CT of the paranasal sinuses before bone marrow or peripheral blood stem cell transplantation. PATIENTS AND METHODS 80 patients with malignant disease underwent coronal CT of the paranasal sinuses prior to transplantation to exclude sinusitis. RESULTS CT revealed sinusitis requesting therapy in 17/80 patients (21%). Patients with leukaemia and non-Hodgkin lymphoma were significantly more affected. Chronic sinusitis was found in two patients, mucosal swelling not requesting therapy in 22, and normal findings in 39. CONCLUSION CT of the paranasal sinuses is advised in patients suffering haemoblastoses with an increased risk of infectious complic…

Ergebnisse und Komplikationen von 616 perkutanen transhepatischen Gallenwegsdrainagen

During nine years, percutaneous transhepatic biliary drainage was carried out 616 times on 563 patients in the Department of Radiology, University of Mainz Medical School. 50.3% were pre-operative and 39% were palliative. More than 80% were necessitated by malignant lesions. Subsequent improvements in biochemical measurements were observed in 82.4% of patients. Complications of the procedure led to the death of five patients (0.8%) and required surgery in nine patients (1.5%). The following complications were observed: biliary peritonitis in 0.6%, sepsis in 1.9%, bleeding in 1.9% and fever higher than 38 degrees C in 16.2%.

Stellenwert der Skelettszintigraphie in der Diagnostik und Verlaufskontrolle des Ewing-Sarkoms

The radiological and scintigraphic findings of 26 patients with histologically proven Ewing's sarcoma were analysed. Three-phase bone scan should be done early in patients presenting with pain and normal radiographs. Perfusion and metabolism of a bone lesion can be assessed by skeletal scintigraphy. Bone metastases are first seen on bone scan. In the follow-up of the patient bone scans at regular intervals are essential to detect bone metastases and tumour recurrence. The scintigraphic findings have to be correlated with radiographs and if these are negative a short-term control is indicated. Three-phase bone scans can assess the tumours response to therapy.

Farbkodierte Volumen-Rekonstruktionen zur dreidimensionalen Darstellung von CT-Daten

PURPOSE To evaluate a technique of colored three-dimensional reconstructions without segmentation. MATERIAL AND METHODS Color-coded volume rendered images were reconstructed from the volume data of 25 thoracic, abdominal, musculoskeletal, and vascular helical CT scans using commercial software. The CT volume rendered voxels were encoded with color in the following manner. Opacity, hue, lightness, and chroma were assigned to each of four classes defined by CT number. Color-coded reconstructions were compared to the corresponding grey-scale coded reconstructions. RESULTS Color coded volume rendering enabled realistic visualisation of pathologic findings when there was sufficient difference in…

Detection of spontaneous echocardiographic contrast within the left atrium by transesophageal echocardiography: spontaneous echocardiographic contrast

Transesophageal echocardiography was performed in 314 patients over a period of 24 months using a 3.5 MHz phased-array system fitted to the distal end of a conventional 12 mm endoscope. In 12 patients (2.6%) transesophageal echocardiography could not be performed because of adverse reaction to the gastroscopic procedure. Side effects were a transient A-V block in one patient and asthmatic attack in another. Mitral valve lesions were found in 99 of 314 patients. In 9 of these 99 patients (11%), including 1 patient with mitral valve stenosis and sinus rhythm, 2 with atrial fibrillation, 3 with disc, and 3 with porcine mitral prosthesis, spontaneous echocardiographic contrast was found within …

Transvaskuläre Fensterung eines dissektierenden Aortenaneurysmas

Interdisziplin�res Polytraumamanagement

Die fruhe klinische Behandlungsphase mehrfachverletzter Patienten ist durch das interdisziplinare Zusammenwirken von Unfallchirurgie, Anasthesie und Radiologie gekennzeichnet. Gemeinsames Ziel dabei ist, lebensbedrohliche Verletzungsmuster umgehend zu diagnostizieren, um adaquate therapeutische Masnahmen einleiten zu konnen. Um diese Anforderungen zu erfullen, bedarf die Radiologie ihrerseits eines standardisierten apparativen, personellen und logistischen Konzeptes zur Durchfuhrung der bildgebenden Diagnostik polytraumatisierter Patienten bei gleichbleibender Qualitat im 24-Stunden-Betrieb. Seit ihrer Einfuhrung entwickelt sich die Mehrschicht-Spiral-CT zum zentralen bildgebenden Verfahren…

Influence of contrast agent dose and image acquisition timing on the quantitative determination of nonviable myocardial tissue using delayed contrast-enhanced magnetic resonance imaging.

BACKGROUND: Delayed contrast-enhanced magnetic resonance imaging (ceMRI) has been shown to identify areas of irreversible myocardial injury due to infarction (MI) with high spatial resolution, allowing precise quantification of nonviable (hyperenhanced) myocardium. The aim of our study was to investigate the size of nonviable myocardium quantitatively as a function of time post-contrast when inversion time is held constant in patients post-myocardial infarction using two contrast agent (CA) doses. METHODS: Nine patients with chronic MI underwent two MR scans on a 1.5 Tesla system. Contrast-enhanced MRI data in two short-axis (SA) slices were continuously acquired until 40 minutes after CA i…

Pneumonia in Febrile Neutropenic Patients and in Bone Marrow and Blood Stem-Cell Transplant Recipients: Use of High-Resolution Computed Tomography

PURPOSE: To obtain statistical data on the use of high-resolution computed tomography (HRCT) for early detection of pneumonia in febrile neutropenic patients with unknown focus of infection. MATERIALS AND METHODS: One hundred eighty-eight HRCT studies were performed prospectively in 112 neutropenic patients with fever of unknown origin persisting for more than 48 hours despite empiric antibiotic treatment. Fifty-four of these studies were performed in transplant recipients. All patients had normal chest roentgenograms. If pneumonia was detected by HRCT, guided bronchoalveolar lavage was recommended. Evidence of pneumonia on chest roentgenograms during follow-up and micro-organisms detected…

Das Onkozytom der Niere

The angiographic findings in ten patients with renal oncocytoma are described. Characteristic features include: absence of encasement, vascular occlusions, arterio-venous shunts and contrast lakes (8/10). Spoke-wheel arrangement of tumor vessels (8/10). Homogeneous tumour contrast during the capillary phase (7/10). Sharp demarcation from the kidney and surroundings (9/10) and a peritumoral halo (4/10). If the suspicion of an oncocytoma is raised by CT examination of a space-occupying lesion (part I), angiography should be performed to confirm the diagnosis and help in planning surgical treatment.

Beurteilung der Durchgängigkeit von koronaren Bypassgefäßen mit einer 2D T2-gewichteten Turbo-Spin-Echo-Sequenz (HASTE) in Atemanhaltetechnik

AIM To evaluate the patency of coronary artery bypass grafts with a 2D T2-weighted breath-hold turbo-spin-echo sequence. METHODS 38 patients with 97 grafts (19 internal mammary artery and 78 saphenous vein grafts) and a total of 120 distal anastomoses were studied at 1.5 Tesla in supine position using a phased array body coil. An ECG gated 2D T2-weighted breath-hold turbo-spin-echo sequence (HASTE) was performed. Reference method was selective coronary angiography. The image material was evaluated independently by two radiologists (observer one, a radiological fellow and the second a staff radiologist). RESULTS Observer 1 reached a sensitivity of 96% (72/75) and a specificity of 91% (20/22)…

Dynamic contrast-enhanced myocardial perfusion imaging using saturation-prepared TrueFISP.

Purpose To develop and test a saturation-recovery TrueFISP (SR-TrueFISP) pulse sequence for first-pass myocardial perfusion imaging. Materials and Methods First-pass magnetic resonance imaging (MRI) of Gd-DTPA (2 mL) kinetics in the heart was performed using an SR-TrueFISP pulse sequence (TR/TE/α = 2.6 msec/1.4 msec/55°) with saturation preparation TD = 30 msec before the TrueFISP readout. Measurements were also performed with a conventional saturation-recovery TurboFLASH (SRTF) pulse sequence for comparison. Results SR-TrueFISP images were of excellent quality and demonstrated contrast agent wash-in more clearly than SRTF images. The signal increase in myocardium was higher in SR-TrueFISP …

Hydro-MRT in der Darmdiagnostik bei Kindern

Purpose A clinical evaluation of hydro-MRI as an alternative method to barium studies in children with abdominal pain of unknown origin is presented. Patients and methods 20 children with abdominal pain of unknown origin aged from 9 - 16 years were examined after oral bowel opacification using 1000 ml of 2.5 % mannitol solution with a 1.0 T MRI system. The investigation was done in 2 planes (coronal and axial) under breath-hold conditions. Imaging procedures included various sequences (T2W HASTE + FS, contrast-enhanced T1W FLASH FS). Suspicious findings in bowel segments and extra-intestinal changes were assessed. Results In 21/24 examinations the small bowel was completely visualized, in 1…

Administration of Second-Generation Extracorporeal Shock Waves without Waterbath for Fragmentation of Extra- and Intrahepatic Bile Duct Stones

First-generation extracorporeal shock-wave sources disintegrate 97% of kidney stones [1, 2]. Recently, in selected patients gallbladder and common bile duct stones were also treated. The technique available so far, however, requires immersion of the patient’s body in a tank of degassed water. The procedure is therefore inconvenient, time consuming, and relatively expensive. The high pressure of shocks (up to 1000 bar) generated by underwater spark discharge causes pain, and general anesthesia is necessary in most patients [3, 4].

Segmentanatomie der Leber in der Computertomographie: Lokalisieren wir die Läsionen richtig?*

Purpose: To evaluate if Couinaud's model using the planes of the major veins is an adequate tool for the presurgical localization of focal liver lesions. Methods: Biphasic helical CT scans were performed on patients evaluated for liver resection using an increased IV bolus of contrast medium (180 ml lopamidol) and 2 mm image reconstruction increments. During the first evaluation, all liver lesions were localized in the conventional way using the planes of the 3 major hepatic veins and the portal trunks as segmental boundaries. In a second review, all lesions were attributed to the nearest peripheral portal branches. The path and the segmental attribution of the portal branches were analysed…

Dynamic19F-MRI of pulmonary ventilation using sulfur hexafluoride (SF6) gas

A new method for dynamic imaging of pulmonary wash-in and wash-out kinetics of inhaled sulfur hexafluoride (SF6) gas was developed. Measurements at the fluorine-19 Larmor frequency were performed in pigs using a gradient echo pulse sequence with 0.5 ms echo time and a measurement time of 9.1 s per image. Dynamic MRI was performed during wash-in and wash-out of SF6 gas in mechanically ventilated porcine lungs. A postprocessing strategy was developed for quantitative determination of wash-out time constants in the presence of noise. Mean wash-out constants were 4.78 ± 0.48 breaths vs. 4.33 ± 0.76 breaths for left and right lung when ventilation was performed with low tidal volume, and 1.73 ± …

Klinische Erfahrungen mit dem Kensey-Katheter-System - Komplikationen und Ergebnisse

Fifteen procedures have been carried out in 14 patients using the Kensey rotation angioplasty system. Sixteen occlusions of the superficial femoral artery, with an average length of 10.2 cm (3 to 24 cm) and one artery with multiple stenoses were treated. The following results were obtained: creation of a lumen, with subsequent balloon dilatation in eight out of fifteen procedures; in two patients the vessels were occluded shortly after the procedure, due to complications (one obstructive plaque and one haematoma); five perforations, three dissections and one peripheral embolus. The total complication rate was 11 out of 15 cases, clinical improvement was obtained in six out of 15 cases.

Chronische thromboembolische pulmonale Hypertonie: Hämodynamische Auswirkungen der selektiven Pulmonalis-DSA mit nicht-ionischem Kontrastmittel

PURPOSE This study evaluates the effects of pulmonary bolus injection of nonionic contrast medium on pulmonary artery pressure and resistance in patients with chronic thromboembolic pulmonary hypertension. METHODS In 39 patients (age 52 +/- 15) haemodynamic measurements were performed during bolus injection of nonionic contrast medium in a control group (I), in moderately severe (II) and severe pulmonary hypertension (III). RESULTS Initial inspiratory arrest caused significant pressure increase in all groups prior to bolus injection (delta PAsyst: 7.1 +/- 6.7 [I], 6.8 +/- 3.9 [II] und 7.2 +/- 7.9 mmHg p < 0.05). However, contrast bolus injection (25.1 +/- 2.3 ml iopamidol, 13.0 ml/s) caused…

Möglichkeiten und Perspektiven der nichtinvasiven Bypassdiagnostik

Ziel: Das Studienziel war die kernspintomographische Evaluierung koronarer Bypassgefase mit der Hast-, Fisp-3-D- und Navigatorsequenz unter besonderer Berucksichtigung der distalen Bypassanastomose.

Perkutan transhepatische Feinkaliber-Cholangioskopie

Percutaneous transhepatic fine calibre cholangioscopy is described. A specially developed transparent instrument is used, which makes it unnecessary to have a steerable endoscope; visualisation of the biliary tree is of diagnostic value for assessing biliary stenoses due to tumours (choice of biopsy site, extent of intraductal radiation therapy) and for the assessment of anastomoses between the biliary system and the gut (condition of the mucosa, stenoses). In the presence of percutaneous biliary drainage, the method has little utility. Extension of the method for treating intraductal stones may be possible if in future a useful lumen can be added to the fine endoscope.

Vollautomatische Detektion und Quantifizierung des Lungenemphysems in Dünnschicht-MD-CT des Thorax durch eine neue, speziell entwickelte Software

Purpose: Introduction of a novel software tool (YACTA - yet another CT analyzer) for detection and quantification of pulmonary emphysema in thin-slice chest MDCT data sets. Materials and Methods: Consisting of grey-level threshold-based algorithms (e. g., region-growing), expert rules and morphological image postprocessing YACTA segments the tracheobronchial tree prior to the detection and quantification of pulmonary emphysema. In addition to general parameters, such as the mean lung density (MLD) and the emphysema index (EI - also described as pixel index PI), the previously described bullae index (BI) is transformed into a three-dimensional parameter for a morphological description of emp…

Die akute Gefäßperforation mit Shuntbildung in den rechten Ventrikel nach perkutaner transluminaler Koronarangioplastie. Kernspintomographischer und dopplersonographischer Nachweis des Shuntflusses

Die Gefasperforation nach transluminaler Koronarangioplastie (PTCA) stellt eine seltene Komplikation dieser etablierten Behandlungsmethode dar. Die Therapie wird bestimmt durch die hamodynamische Beeintrachtigung des linken oder rechten Ventrikels. Wir berichten uber den Fall einer Gefasperforation nach PTCA mit Shuntbildung von der rechten Koronararterie in den rechten Ventrikel, wobei der Shuntflus sowohl kernspintomographisch als auch dopplersonographisch dargestellt werden konnte.

Quantifizierung von Atelektasen bei kontrollierter Beatmung: Spiral-CT versus dynamische Einzelschicht-CT

Ziel: Dynamische CT-Untersuchungen (dCT) erlauben die Darstellung und Quantifizierung ventilierter Lungenflache und Atelektasenbildung wahrend kontinuierlicher Beatmung. Diese Studie ­vergleicht eine quantitative Auswertung einer infrakarinalen dCT-Einzelschicht mit der einer Spiral-CT der gesamten Lunge, um zu untersuchen, ob eine dynamisch gemessene Einzelschicht bezuglich der intrapulmonalen Atelektasenverteilung reprasentativ fur die Gesamtlunge ist. Material und Methoden: An 8 gesunden Schweinen erfolgte eine dCT (Schichtdicke 1 mm, zeitliches Inkrement 100 ms) wahrend kontinuierlicher Beatmung, gefolgt von einer Spiral-CT der gesamten Lunge (Schichtdicke 2 mm; Pitch 1,5; Inkrement 2 m…

Induction of DNA single-strand breaks by 131I and 99mTc in human mononuclear blood cells in vitro and extrapolation to the in vivo situation.

The radionuclides (131)I and (99m)Tc are frequently used for therapy of benign and malignant thyroid disease ((131)I) and for diagnosis of thyroid and other diseases ((99m)Tc). However, the levels of DNA single-strand breaks (SSBs) induced in cells of patients after administration of (131)I and (99m)Tc are not known. In this study, we measured the number of SSBs per cell induced by (131)I and (99m)Tc in vitro, extrapolated the results to the clinical situation, and assessed their biological relevance by comparing levels of SSBs induced after therapeutic administration of (131)I and (99m)Tc to those induced by endogenous processes or by occupational exposure to genotoxic substances. A linear…

Einfluss von Typ-II-Endoleaks auf die Größenänderung und Hämodynamik experimenteller Aortenaneurysmen nach endovaskulärer Therapie

PURPOSE To evaluate the aneurysm volume and the intra-aneurysmatic pressure and maximal pressure pulse (dp/dtmax) in completely excluded aneurysms and cases with endoleaks. MATERIALS AND METHODS In 36 mongrel dogs, experimental autologous aneurysms were treated with stent-grafts. All aortic side branches were ligated in 18 cases (group I) but were preserved in group II (n = 18). Aneurysm volumes were calculated from CT scans before and after intervention, and from follow-up CT scans at 1 week, 6 weeks and 6 months. Finally, for hemodynamic measurements, manometer-tipped catheters were introduced into the excluded aneurysm sac (group I and II), selectively in endoleaks (group II), and intral…

Eine Mannitollösung als orales Kontrastmittel in der pelvinen MRT

PURPOSE Improvement of pelvic MRI using peroral administration of an aqueous mannitol solution. METHODS We retrospectively evaluated magnetic resonance examinations of 72 patients with suspected or proven pelvic abnormalities: In 36 patients, no bowel marking was carried out. In further 36 patients, we performed a contrast enhancement of the bowel by oral application of 1000 ml of an aqueous mannitol solution. RESULTS 8/36 (22%) patients suffered from diarrhoea, nausea or meteorism as a result of mannitol application. In group 2, an excellent bowel marking of the small intestine could be obtained in 36/36 (100%) patients. Contrast enhancement of the bowel significantly improved delineation …

Artefaktreduzierung bei der Lungenemboliediagnostik mittels Spiral-CT unter Verwendung eines Kochsalzbolus

nary Arteries Using a Saline Push. Purpose: To improve the diagnostic efficacy of bolus-enhanced spiral CT (SCT) in the detection of pulmonary embolism using a saline push immediately after bolus injection of the contrast medium. Patients and Methods: The study included 90 patients with suspected acute or chronic pulmonary embolism. The CT scan was performed in a caudocephaled direction. In Group I (n=60) we applied a bolus contrast injection (120 ml, 3 ml/s, 300 mg J/ml), after a median delay of 25 s. Group II (n = 30) had the same contrast injection which was immediately followed by an additional saline push (60 ml, 2 ml/s). Streak artifacts originating from high contrast concentrations i…

19F-MRI of perflubron for measurement of oxygen partial pressure in porcine lungs during partial liquid ventilation

A method for in vivo measurement of oxygen partial pressure (pO2) in porcine lungs during partial liquid ventilation (PLV) with perflubron (PFOB) was developed. A pulse sequence for high-resolution MRI of the distribution of PFOB in the lung after intratracheal administration was developed as well. Moreover, quantitative measurements of longitudinal relaxation time T(1) of (19)F resonances for assessment of regional pO2 are described. Due to the need to acquire data during a single expiratory breathhold, only low SNRs were achieved in vivo. Therefore, simulations were performed to investigate the influence of background noise on T(1) values calculated from data with low SNR. Based on these …

Focal airtrapping at expiratory high-resolution CT: comparison with pulmonary function tests

This study was undertaken to determine prevalence, extent, and severity of focal airtrapping at expiratory high-resolution CT, and to compare focal airtrapping with age, gender, pulmonary function tests, and blood gas analysis. Two-hundred seventeen patients with and without pulmonary disease underwent paired inspiratory/expiratory high-resolution CT. Six scan pairs with corresponding scan levels were visually assessed for focal – not diffuse – airtrapping using a four-point scale. Pulmonary function tests and blood gas analysis were available for correlation in all patients (mean interval 5 days). Focal airtrapping with lower lung predominance was observed in 80 % of patients. Twenty-six o…

Analysis of radiolucent gallstones by computed tomography for in vivo estimation of stone components.

. Successful oral litholytic and other non-operative therapies of gallstones require exact determination of the stone components. Since computed tomography (CT) provides highly sensitive measurement of density, we performed a study to evaluate whether CT measurement of stone density allows a prediction of the composition of radiolucent gallstones. Twenty-eight patients presenting with 29 radiolucent gallbladder (n= 17) or common bile duct stones (n=12) were included. Prior to operative or endo-scopic therapy the attenuation values (Hounsfield Units, HU) were assessed in vivo by CT under standardized conditions (Somatom II, 125 KV, 130 mAs). After surgical or endoscopic stone removal the con…

MR-tomographische Messung der diastolischen Relaxation hypertrophierter linker Ventrikel mit Single-slice-multi-phase-Technik

In order to assess diastolic ventricular function in hypertensive patients, a single-slice multiphase sequence was used in order to measure contraction and early diastolic relaxation. There was no difference in the contraction velocity between hypertensives and normals (Vsys. n.r. = 56.1 +/- 13.8% LVDV/s vs. 51.7 +/- 8.6% LVEDV/s, stat, n. sign.). Early diastolic relaxation velocity in hypertensives was reduced as compared with the control group (Vdiast. 1n.r. = 37.9 +/- 13.1% LVEDV/s vs. 47.1 +/- 9.6% LVEDV/s, p < 0.05). There was no linear relation between abnormal relaxation and the extent of myocardial hypertrophy. Hypertensives with myocardial hypertrophy frequently had reduced early d…

Niederfeld MR-Arthrographie der Schulter: Erste Ergebnisse mit einem offenen 0,2 T MR-System

PURPOSE To assess the practicability and image quality of doing MR arthrography of the shoulder using a 0.2T system. PATIENTS AND METHOD 60 patients (24 with chronic instability, 36 with impingement syndrome) were examined in an open 0.2T MR apparatus (Magnetom Open, Siemens). After the intra-articular injections of 15-20 ml of a 2 mmol Gd-DTPA solution, coronary STIR, T1-weighted, sagittal and axial T2*-weighted FLASH 2D sequences were performed. 21 patients subsequently underwent surgery. RESULTS Image quality of the T1- and T2*-weighted FLASH 2D sequences was regarded as good or adequate and movement artifacts were minor or moderate. STIR sequences were statistically significantly worse …

Systemic pulsatile pressure in type II endoleaks after stent grafting of experimental abdominal aortic aneurysms.

Purpose: To investigate pressure and maximum rate of rise of systolic pressure (peak dP/dt) in completely excluded aneurysms and endoleaks to determine the hemodynamic impact of endoleaks. Methods: In mongrel dogs (n = 36) experimental aneurysms were created by insertion of a patch (portion of rectus abdominis muscle sheath) into the infrarenal aorta. In group I (n = 18), all aortic branches of the aneurysm were ligated and all aneurysms were completely excluded by stent grafts. Group II (n = 18) consisted of aneurysms with patent aortic side branches that represented sources of endoleaks. One week (n = 12), six weeks (n = 12), and six months (n = 12) after stent grafting, hemodynamic measu…

MR-Mammographie zur Responsekontrolle bei primärer Chemobrachytherapie des BET-inoperablen Mammakarzinoms

Ziel: Evaluierung (1) moglicher storender Effekte neoadjuvanter Chemobrachytherapie auf die MR-Mammographie, (2) der Eignung der MRM zur Bestimmung der Resttumorgrose nach Therapie und (3) der Eignung der MRM zur Prognose des Gesamtansprechens nach den ersten Therapiezyklen. Methoden: 14 Patientinnen, die an einer praoperativen Tumorreduktionstherapie (4 Zyklen Chemotherapie kombiniert mit interstitieller Radiotherapie) teilnahmen, wurden mittels dynamischer MR-Mammographie (1 T, zeitliche Auflosung 93 s, raumliche Auflosung 1,9 mm, 0,1 mmol/kg GdDTPA) vor Therapie, nach den ersten beiden Chemotherapiezyklen, nach der Radiotherapie und dem dritten Zyklus sowie nach Therapieabschluss untersu…

Diagnose und Verlaufsbeurteilung eines intramuralen Hämatoms der Aorta ascendens mit der Magnetresonanztomographie

Diagnostik von Pleuraergüssen und Atelektasen: Sonographie und Radiologie im Vergleich

In a prospective study it was shown that chest ultrasonography is superior to conventional x-ray diagnosis of recumbent patients in diagnosing pleural effusion and lung atelectasis. In 110 supine radiographs we found a sensitivity of 47% and a specificity of 71% for right pleural effusions and a sensitivity of 55% and a specificity of 93% for left pleural effusions in comparison to 110 sonographic examinations. The results of supine radiographs in detection of atelectasis were less efficient: sensitivity for the right side: 7%; sensitivity for the left side: 13.5%. Hence, the knowledge of chest ultrasonographic diagnosis can improve the interpretation of supine radiographs.

Graves ophthalmopathy: role of MR imaging in radiation therapy.

Twenty-three patients with Graves ophthalmopathy who underwent radiation therapy were monitored by means of magnetic resonance (MR) imaging. T2 relaxation times of extraocular muscles and orbital fat, areas of extraocular muscles, and degree of exophthalmos were measured by means of MR imaging at the beginning, at the end, and 3 months after completion of radiation therapy. As a result, patients with primarily elevated T2 times of extraocular muscles showed a better therapy response regarding muscle thickening than patients with primarily normal T2 times. Elevated T2 times, which probably represent acute inflammatory changes, were markedly decreased at the end of therapy. Therefore, quantit…

Lung density distribution in dynamic CT correlates with oxygenation in ventilated pigs with lavage ARDS † †This study contains parts of the doctoral thesis of Elena Ribel.

Background Fast dynamic computed tomography (dCT) has been used to assess regional dynamics of lung inflation and deflation processes. The aim of this study was to relate ventilation-induced changes in lung density distribution, as measured over several respiratory cycles by dCT, to oxygenation and shunt fraction in a lavage acute respiratory distress syndrome model. Methods Six anaesthetized pigs underwent pressure-constant ventilation (F I O2=1.0, inspiratory:expiratory ratio=1:1) before and after induction of lung damage by saline lavage. Mean airway pressure ( P a μ w μ ) was varied (8, 13, 18, 23, 28, 33, and 38 cm H2O) in random order. At each P a μ w μ level, dCT acquisitions were pe…

Indirekte MR-Arthrographie zur Verlaufskontrolle nach autologer osteochondraler Transplantation

Purpose: To evaluate the spectrum of findings in indirect MR-arthrography following autologous osteochondral transplantation. Patients and Methods: 10 patients with autogenous osteochondral homografts underwent indirect MR-arthrography at three, 6 and 12 months postoperatively. The MR protocol at 1.5 T comprised unenhanced imagings with PD- and T 2 -weighted TSE-sequences with and without fat-suppression as well as T 1 -weighted fat-suppressed SE-sequences before and after iv. contrast ad ministration and after active joint exercise. Image analysis was done by two radiologists in conference and comprised the evaluation of signal intensity (Sl) and integrity of the osseous plug and the carti…

Prospective comparison of CT angiography of the legs with intraarterial digital subtraction angiography.

The aim of this study was to determine the accuracy of CT angiography (CTA) with a single spiral acquisition for the diagnosis of arterial stenoses and occlusion in patients with peripheral vascular occlusive disease.In a prospective study, intraarterial digital subtraction angiography and i.v. CTA from the groin to the lower calves were performed on 50 patients with vascular occlusive disease. Maximum-intensity-projection images in multiple views were produced. The accuracy of CTA with and without analysis of the axial scans was determined with digital subtraction angiography as the standard.The sensitivities of CTA were 100% for the diagnosis of femoral artery occlusion, 100% for the dete…

Endovascular Aneurysm Repair

Background — The purpose of the present study was to systematically analyze the histopathologic organization processes in excluded aneurysms after endovascular stenting and to develop a noninvasive monitoring method for these processes using MRI. Methods and Results — In 36 mongrel dogs, autologous aortic aneurysms were created. Endovascular treatment was performed using covered stents. Follow-up was after 1 week, 6 weeks, and 6 months. MRI was performed with T 2 -weighted turbo-spin-echo sequences and T 1 -weighted spin-echo sequences and was repeated after contrast bolus with gadolinium. Histopathologic findings were correlated to signal intensities (SIs) of MRI images. SIs of distinct a…

Automatic detection and quantification of ground-glass opacities on high-resolution CT using multiple neural networks: comparison with a density mask.

We compared multiple neural networks with a density mask for the automatic detection and quantification of ground-glass opacities on high-resolution CT under clinical conditions.Eighty-four patients (54 men and 30 women; age range, 18-82 years; mean age, 49 years) with a total of 99 consecutive high-resolution CT scans were enrolled in the study. The neural network was designed to detect ground-glass opacities with high sensitivity and to omit air-tissue interfaces to increase specificity. The results of the neural network were compared with those of a density mask (thresholds, -750/-300 H), with a radiologist serving as the gold standard.The neural network classified 6% of the total lung a…

Chronic Thromboembolic Pulmonary Hypertension: Pre- and Postoperative Assessment with Breath-hold MR Imaging Techniques

To evaluate the potential of breath-hold magnetic resonance (MR) imaging techniques in morphologic and functional assessment of patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after surgery.Thirty-four patients with CTEPH were examined before and after pulmonary thromboendarterectomy (PTE). For morphologic assessment, contrast material-enhanced MR angiography was used; for assessment of hemodynamics, velocity-encoded gradient-echo sequences and cine gradient-echo sequences along the short axis of the heart were performed. Contrast-enhanced MR angiography was compared with selective digital subtraction angiography (DSA) for depiction of central thromboembolic m…

In-vitro-Untersuchung von biologischen und technischen Herzklappenprothesen im MRT: Beurteilung möglicher Anziehung und Erhitzung der Implantate

PURPOSE In vitro evaluation of possible deflection and heating of present-day prosthetic heart valves during MR imaging at 1.5 T. METHODS 17 prosthetic heart valves, 12 technical and 5 biological, were investigated using a 1.5 Tesla Siemens Vision system. Deflection was measured at the edge of a 1.5 Tesla superconducting magnet. Each valve was then submerged in a vial of a 1/1 electrolyte solution and temperature was measured before and after imaging with a turbo-spin-echo sequence (TR 5200 ms, TE 138 ms, Flip angle 180 degrees, acquisition time 10.5 minutes, length of echo train 29). MR imaging was performed with phase encoding parallel and perpendicular to the plane of the valves. RESULTS…

Analyse von Bronchien in der Multislice-CT

Es wird eine Methode zum objektiven Bestimmen der Wanddicke und des Gesamt durchmessers von Bronchien in der 3-dimensionalen Computertomographie vorgestellt. Die Methode wurde erfolgreich an Phantomen evaluiert. Erste Studien sowohl an tierischen als auch an menschlichen Bronchien verliefen erfolgversprechend.