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…

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…

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…

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…

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…

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…

Area at Risk and Viability after Myocardial Ischemia and Reperfusion Can Be Determined by Contrast-Enhanced Cardiac Magnetic Resonance Imaging

<i>Background/Aims:</i> Clinical differentiation between infarcted and viable myocardium in the ischemic area at risk is controversial. We investigated the potential of contrast-enhanced cardiac magnetic resonance imaging (ceCMRI) in determining the area at risk 24 h after ischemia. <i>Methods:</i> Myocardial ischemia was induced by percutaneous coronary intervention of the left anterior descending coronary artery in pigs. Coronary occlusion time was 30 min in group A, which caused little myocardial infarction and 45 min in group B, which led to irreversible damage. 24 h after reperfusion ceCMRI was performed at 2 and 15 min after administration of gadolinium-diethyl…

True-lumen collapse of the ascending aorta in acute type A aortic dissection

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…

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…

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…

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 …

Rapid Musculoskeletal Magnetic Resonance Imaging Using Integrated Parallel Acquisition Techniques (IPAT) - Initial Experiences

Purpose To investigate the feasibility of using multiple receiver coil elements for time saving integrated parallel imaging techniques (iPAT) in traumatic musculoskeletal disorders. Material and methods 6 patients with traumatic derangements of the knee, ankle and hip underwent MR imaging at 1.5 T. For signal detection of the knee and ankle, we used a 6-channel body array coil that was placed around the joints, for hip imaging two 4-channel body array coils and two elements of the spine array coil were combined for signal detection. All patients were investigated with a standard imaging protocol that mainly consisted of different turbo spin-echo sequences (PD-, T (2)-weighted TSE with and w…

Softwareassistierte CT-Nachverarbeitung am Beispiel der Karotiden

Ziel der Arbeit: Es sollte ein Softwareassistent fur die automatisierte Auswertung von CT-Angiographien entwickelt werden, der die Visualisierung des Gefaslumens und eine quantitative Auswertung von Stenosen ermoglicht. Die klinische Erprobung erfolgt am Beispiel der A. carotis. Methodik: Bei insgesamt zwolf Patienten mit Verdacht auf eine hohergradige Stenose der Karotiden wurde eine CT-Angiographie (CTA) mit einem Mehrzeilen-CT durchgefuhrt. Diese Daten wurden mit dem neuen Softwareassistenten analysiert und ausgewertet. Die Ergebnisse verglich man mit der digitalen Subtraktionsangiographie (DSA). Ergebnisse: Die Nachverarbeitungszeit der CT-Datensatze mit Hilfe des Softwareassistenten li…

The Shoulder Girdle

The shoulder girdle is an anatomically complex structure consisting of the scapula, clavicula, proximal humerus, and their articular connections. The wide range of motion is provided by the glenohumeral joint and the two shoulder girdle joints, the acromioclavicular and sternoclavicular joints.

Anteil des frühen systolischen Flussanstiegs am antegrad fließenden Gesamtvolumen bei Phasenkontrast-Flussmessungen in Atemanhaltetechnik

Purpose To evaluate the contribution of early systole for the assessment of antegrade aortic flow volume by breath-hold velocity-encoded magnetic resonance (MR) flow measurements. Materials and methods Expiratory breath-hold fast low-angle shot (FLASH) phase-contrast flow measurements (temporal resolution tRes 61 msec, shared phases) perpendicular to the proximal ascending aorta and short axis true fast imaging with steady-state precession (TrueFISP) cine MR ventriculometry (tRes 34.5 msec) were performed in ten healthy male volunteers on a 1.5 T MR system (Sonata, Siemens Medical Solutions). Antegrade aortic flow volume (AFV) and left ventricular stroke volume (LV-SV) were evaluated using …

Kontrastverstärkte MR-Angiographie abdomineller Gefäßean einem 1.0 T-System*

Purpose To evaluate the efficacy of breath-hold, three-dimensional, contrast-enhanced magnetic resonance angiography with a 1.0 T system for imaging the abdominal vessels in comparison to conventional arteriography (CA). Methods The abdominal aorta and visceral arteries were studied in 54 patients (60 examinations) on a 1.0 T scanner using an ultrafast gadolinium-enhanced gradient-echo sequence with the following parameters: TR/TE = 3.8/1.4 ms, flip angel 25 degrees, matrix 198 x 256, field 380-420 mm, pixel size 1.9 x 1.48 mm2, slice thickness 1.5-2.5 mm, acquisition time 22-26 sec. Individual circulation times were determined by a test bolus before each MR angiography. Conventional arteri…

The Effect of Tiotropium/Olodaterol versus Salmeterol/Fluticasone on Left Ventricular Function and Lung Hyperinflation in Patients with COPD

Duplexsonographie der normalen Pfortader

In 50 normal subjects flow velocity and direction on the portal vein was measured by ultrasonic duplex system. The measurements revealed at a mean diameter of 9.7 mm, a mean flow velocity of 15.2 +/- 2.6 cm/s, corresponding to a volume flow of 693 +/- 235 ml/min. Postprandially this increased to 880 +/- 269 ml/min. Inter-observer and day to day measurements demonstrated good reproducibility. Thus, this simple non-invasive method is well suited for quantitative assessment of the portal vein system in portal hypertension, thrombosis or after shunt operations.

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…

Early Detection of Sternal Dehiscence by Conventional Chest X‐Ray

BACKGROUND Diagnosis of sternal dehiscence after sternotomy for cardiac surgery is still made clinically. The aim of this study was to identify radiographic signs of sternal dehiscence by routine chest X-ray (CXR) in patients with and without clinically diagnosed sternal dehiscence. METHODS 75 patients (group I: 65 +/- 9.3 years, f/m = 12/63) with clinically diagnosed sternal dehiscence, necessitating surgical revision and 75 patients with uneventful sternal healing (matched to group I by age, sex, preoperative risk factors and surgical procedures; group II: 66 +/- 9.0 years, f/m = 12/63) were included in this study. Serial CXRs immediately after surgery until re-intervention or discharge w…

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…

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…

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…

Aortenisthmusstenose bei Erwachsenen: operative Korrektur - mittel- und langfristige Ergebnisse

Fragestellung Ziel dieser retrospektiven Untersuchung war es, die Mittel- und Langzeitergebnisse der operativen Korrektur von Aortenisthmusstenosen (ISTHA) bei Erwachsenen zu erfassen. Patienten und Methodik Zwischen August 1985 und Januar 1999 wurden 20 Patienten (8 Frauen, 12 Manner) wegen ISTHA im Alter 19–60 Jahren (im Mittel 33 Jahre) operiert. Alle Patienten fielen klinisch durch Bluthochdruck der oberen Extremitaten auf (im Mittel 177/92 mmHg). Bei 9 Patienten von 16 (56%) handelte es sich um einen Zufallsbefund (bei 4 konnte dies nicht eruiert werden). Eine eingeschrankte praoperative Belastbarkeit wiesen 13 Patienten (65%) auf. Herzrhythmusstorungen zeigten sich bei 3 Patienten (15…

Duplexsonographie abdomineller Gefäße

Duplex sonography is a non-invasive procedure which permits the determination of flow velocity and direction in visceral vessels. Results in 50 normals have shown that small arteries can be evaluated in about 50% of cases. The portal venous system can be demonstrated in all cases; average flow velocity and volume is 15.2 +/- 2.8 cm/s and 694 +/- 230 ml/min, corresponding with the values obtained by invasive methods. Clinical application for duplex examinations can be found in portal hypertension, varices, thromboses, aneurysms and transplant kidneys.

Morphologische und funktionelle Evaluation pulmonaler Gefäßanomalien mittels schneller MR-Techniken

Purpose: To evaluate breath-hold MR techniques for morphologic and functional assessment of vascular abnormalities of the pulmonary vasculature. Patients and Methods: 13 patients aged 11 to 60 years with different vascular abnormalities of the pulmonary vasculature (5 patients with 16 arteriovenous malformations, 8 patients with partial anomalous pulmonary venous return) underwent MR imaging at 1.5 T. For morphological assessment, a contrast-enhanced 3D MR angiography (ce-MRA) was performed after a timing run. Segmented cine- and velocity-encoded GRE sequences were used for delineation of associated cardiac septal defects and for determination of systemic left-to-right or intrapulmonary shu…

Multidetector Computed Tomography Angiography (MD-CTA) of Coronary Artery Bypass Grafts – Update 2017

Coronary artery bypass grafting (CABG) is still an important therapeutic approach in the treatment especially of advanced coronary artery disease. In this study, we elucidate the current role of multidetector computed tomography angiography (MD-CTA) in imaging patients after CABG surgery.This study is based on recent reports in the literature (2007 - 2016) on imaging of CABG using 64-slice MD-CT scanners and beyond. We included 13 reports that compared ECG-gated MD-CTA with conventional invasive coronary angiography (ICA) as the reference standard for the assessment of graft patency and for the detection of 50 % stenoses. These studies had to provide absolute values for true-positive, true-…

Multicenter, double-blind, randomized, intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for Breast MR imaging (DETECT Trial).

To intraindividually compare 0.1 mmol/kg doses of gadobenate dimeglumine and gadopentetate dimeglumine for contrast material-enhanced breast magnetic resonance (MR) imaging by using a prospective, multicenter double-blind, randomized protocol.Institutional review board approval and patient informed consent were obtained. One hundred sixty-two women (mean age, 52.8 years ± 12.3 [standard deviation]) enrolled at 17 sites in Europe and China between July 2007 and May 2009 underwent at least one breast MR imaging examination at 1.5 T by using three-dimensional spoiled gradient-echo sequences. Of these, 151 women received both contrast agents in randomized order in otherwise identical examinatio…

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…

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

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…

Neue Entwicklungen in der MRT des Thorax

Wegen technischer und physikalischer Einschrankungen wurde die MRT bisher nur selten zur Darstellung der Lunge eingesetzt. Neue Entwicklungen haben allerdings die Moglichkeiten der anatomischen Darstellung mittels MRT erheblich verbessert und gleichzeitig neue Perspektiven fur funktionelle Darstellungen eroffnet. Dazu gehoren Techniken zur funktionellen Untersuchung der Perfusion (Kontrastmittel, MR-Angiographie) und der Ventilation der Lunge (inhalierte aerosolierte Kontrastmittel, Sauerstoff, hochpolarisierte Edelgase [He-3, Xe-129] und fluorinierte Gase [SF6]). Die Gleichmasigkeit der Ventilation, Bestimmung von Lungenvolumina, Grose der Luftraume, intrapulmonale Sauerstoffkonzentration,…

Hyperplastic callus formation in osteogenesis imperfecta: CT and MRI findings.

Hyperplastic callus formation is a noteworthy condition in patients with osteogenesis imperfecta because it often mimicks osteosarcoma on radiography. The findings of CT and MRI in hyperplastic callus formation have not been reported. In the presented case, MRI demonstrated contrast enhancement and edema of the surrounding soft tisssue, consistent with benign as well as malignant disease. Computed tomography showed a calcified rim of the lesion which may be a useful feature to rule out osteosarcoma in this condition.

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…

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 …

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.

Darmkontrastierung bei der abdominellen Computertomographie: Wasser oder Kontrastmittel?

The suitability of water as an oral or rectal contrast medium for abdominal CT was studied in 56 patients and compared with an iodine-containing water-soluble contrast medium (ioxital amino acid). In some cases it was impossible to differentiate gastrointestinal structures from extraluminal fluid collections (cystic tumours, ascites, abscesses) and there was poor filling of distal small bowel and colon. The routine use of water can, therefore, not be recommended. In some cases, however, water can result in improved image quality by reducing artifacts and improving the demonstration of the mucosa.

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)…

Okkulte Fraktur einer Achillessehnenossifikation ohne begleitende Sehnenruptur

Ossification of the Achilles tendon is the result of a traumatic, hypoxic injury of the tendon. The usually asymptomatic ossification has a clinical importance only in case of a new trauma. We report about a patient with an isolated fracture of the ossification without an accompanying rupture of the Achilles tendon. Because of the radiologically "occult" fracture the diagnosis could only be verified by MRI. With a conservative treatment without resection of the ossification we could reach painless recovery.

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 …

Ectasia and Aneurysm of the Right Coronary Artery Resulting From a Shunt to the Coronary Sinus

A 65-year-old woman presented with a systolic-diastolic murmur. Further MRI investigations as well as angiography revealed an arteriovenous shunt to the coronary sinus via an enlarged right coronary artery (Figure 1A⇓ and 1B⇓). The distal part of this coronary artery was transformed to a large coronary aneurysm of such extent that the left atrium was compressed …

A multicenter, site-independent, blinded study to compare the diagnostic accuracy of contrast-enhanced magnetic resonance angiography using 1.0M gadobutrol (Gadovist) to intraarterial digital subtraction angiography in body arteries.

Abstract Purpose Prospective evaluation of diagnostic accuracy of single field-of-view contrast-enhanced MR Angiography (ceMRA) with 1.0 M gadobutrol compared to intraarterial DSA in body arteries. Materials and methods In an European multicenter study 179 patients underwent ceMRA and DSA. For each indication five prospectively defined vessel segments were evaluated by local investigators onsite and by three site-independent blinded readers (BR) independently. Results The agreement between ceMRA and DSA diagnosis was statistically significant in the onsite (96.6%) and blinded reader (86.6–90.2%) evaluation. Sensitivity, specificity, accuracy, positive (PPV) and negative predictive values (N…

Assessment of the distal anastomosis of coronary artery bypass grafts with a 2D T2-weighted turbo spin echo sequence and correlation to conventional coronary angiography

Abstract Objective The aim of the study was to evaluate the patensies of the distal anastomoses of coronary artery bypass grafts and to detect graft stenoses and occlusions with a magnetic resonance (MR) spin echo sequence. Patients and methods One hundred and eighty-five patients with 481 distal anastomoses were examined with a 1.5 T MR scanner and coronary angiography. A 2-dimensional T2-weigthed breath-hold half-Fourier acquisition single-shot turbo spin echo sequence (Haste) was performed. All images were evaluated independently by a radiologist and cardiologist and compared to the conventional coronary angiography. The observers were blinded to the coronary angiography findings, but in…

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).

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…

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.

Arthrose und Osteoporose - Wirklich eine inverse Relation?

Objective Increasing bone mineral density (BMD) has been found in several studies in patients with osteoarthritis (OA). Therefore, the simultaneous occurrence of osteoporosis (OP) and OA is denied by many clinicians. Because of our clinical impression, however, we suggest that we have to consider a common occurrence. In the present study we have examined the relationship between osteoathritis of the knee or the hip and osteoporosis. Method The BMD of the lumbar spine and the proximal femur of 117 OA patients (82 postmenopausal female patients aged 50-83 and 35 male patients aged 36-86 years) who subsequently required hip or knee replacements, but were otherwise healthy, was measured by dual…

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…

Kernspintomographische Flussquantifizierung in Koronargefäßen zur Evaluierung hochgradiger Koronarstenosen

Ziel: Zweck der Studie war die Bestimmung des intrakoronaren Blutflusses im Verhaltnis zum Aortenfluss bei Patienten mit hochgradigen Koronarstenosen. Die MR-Flussmessung wurde bei 15 Patienten in 18 Koronargefasen durchgefuhrt. Zur Flussmessung eine segmentierte 2-D-Flash-Sequenz mit einer zeitlichen Auflosung von 110 bzw. 125 ms verwendet. Der mittlere Koronarfluss im Verhaltnis zum aortalen Fluss war bei Patienten mit hochgradigen Koronarstenosen signifikant (p < 0,001) erniedrigt. Die MR-Phasenkontrastmethode ermoglicht eine genaue Bestimmung des Blutflusses in Koronargefassen und in Korrelation zum Aortenfluss eine Aussage uber hochgradige Koronarstenosen. Weiterentwicklungen der Metho…

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…

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 …

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…

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…

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…

Unusual manifestation of an osteoid osteoma of the capitate.

A case of osteoid osteoma of the capitate in a 29-year-old male is reported. The patient suffered from unspecific clinical findings and a 3-year history of uncharacteristic wrist pain. Conventional radiographs of the wrist revealed a circumscribed sclerosis in the proximal part of the capitate bone beside a diffuse demineralisation of the carpal bones. Magnetic resonance imaging demonstrated a circumscribed, tumorous lesion with marked enhancement after IV administration of contrast agent and a highly calcified nidus, which was sharply demarcated by a small rim of granulation tissue from the surrounding spongious bone. Based on MRI findings, the diagnosis of an osteoid osteoma was establish…

The Benefit of Multislice CT in the Emergency Room Management of Polytraumatized Patients

The early treatment of polytraumatized patients needs an effective and standardized approach. Reducing time requirements for the primary diagnostic evaluation is a major concern in the early phase of polytrauma management. Multislice-CT (MSCT) is a quick and reliable method for the initial diagnostic evaluation. Computed tomography provides more detailed and more consistent information than conventional radiography. It has the great advantage of allowing rapid examination of the head, vertebral column, chest, abdomen and pelvis during one single examination. The CT-suite needs to be adequately equipped for resuscitation and reanimation, which is done parallel to the radiological investigati…

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 …

Die Chronisch rekurrierende multifokale Osteomyelitis (CRMO)*: - Teil 2 Klinisch-radiologisch-histopathologische Studie zum kindlich-jugendlichen „Beckentyp” bei 11 Patienten -

We report about the juvenile and adolescent pelvic type of CRMO in 7 girls and 4 boys. The results show from solitary up to 7 pelvic lesions (average 3 lesions) predominantly in the acetabular and paraacetabular region (sometimes with hip joint effusion as a sign for concomitant coxitis).Tc99m-bone-scan is helpful to evaluate exactly the pattern of bone affection. We find 3 stages of an primarily chronic, non-purulent osteomyelitis going along with a "plasma-cell-sclerotic process", leading to a Garre-type sclerosing end-stage, which probably heals after some years spontaneously, projecting on clinical symptoms and radiological appearance. The concomitant coxitis ("sympathetic coxitis") is …

Hamartoma of the triceps surae muscle.

A 9-year-old, otherwise healthy girl presented with a 5-year history of pain in her right calf with retarded growth and development of an equinus contracture of her right leg. Magnetic resonance imaging showed an irregular mass with heterogeneous enhancement after contrast in her right triceps surae muscles, especially the soleus. Histological studies of this triceps surae muscle tissue revealed a haphazard distribution of adipose and connective tissue, striated and smooth muscle cells, vessels and lymphoid follicles, as well as nerve bundles which, together, were considered components of a hamartoma.

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…

Diagnostic performance of gadobenate dimeglumine enhanced MR angiography of the iliofemoral and calf arteries: a large-scale multicenter trial

OBJECTIVE. The purpose of this study was to compare gadobenate dimeglumine–enhanced MR angiography and unenhanced time-of-flight MR angiography for the detection of significant peripheral arterial occlusive disease using digital subtraction angiography as our reference standard. SUBJECTS AND METHODS. Two hundred seventy-two patients underwent MR angiography and digital subtraction angiography of the iliofemoral arteries. MR angiography was performed before (2D time-of-flight acquisitions) and after (spoiled gradient-echo acquisitions) the administration of 0.1 mmol/kg of gadobenate dimeglumine at 1–2 mL/s. Contrast-enhanced MR angiography and digital subtraction angiography of the calf arte…

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…

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)…

MRI of the pulmonary parenchyma.

Imaging of the pulmonary parenchyma represents a unique challenge for MRI. Limited signal is caused by low proton density, susceptibility artifacts, and physiological motion (cardiac pulsation, respiration). Recently, further improvements in MRI techniques have widened the potential for investigations of pulmonary parenchymal disease. These include very short echo times, ultrafast turbo-spin-echo acquisitions, projection reconstruction technique, breathhold imaging, ECG triggering, contrast agents (perfusion imaging, aerosols), sodium imaging, hyperpolarized noble gas imaging, and oxygen enhancement. By using widely available techniques, MRI is helpful in the assessment of (a) acute alveoli…

Quantification of pulmonary blood flow (PBF): validation of perfusion MRI and nonlinear contrast agent (CA) dose correction with H(2)15O positron emission tomography (PET).

Validation of quantification of pulmonary blood flow (PBF) with dynamic, contrast-enhanced MRI is still missing. A possible reason certainly lies in difficulties based on the nonlinear dependence of signal intensity (SI) from contrast agent (CA) concentration. Both aspects were addressed in this study. Nine healthy pigs were examined by first-pass perfusion MRI using gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) and HO positron emission tomography (PET) imaging. Calculations of hemodynamic parameters were based on a one-compartment model (MR) and a two-compartment model (PET). Simulations showed a significant error when assuming a linear relation between MR SI and CA dose in the …

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.

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 …

Konzepte zur Behandlung von Kniegelenkluxationen und Ergebnisse

Grundlagen: Luxationen des Kniegelenkes sind seltene, jedoch sehr schwere Verletzungen. Daher ist zur optimalen Behandlung ein uberpruftes Konzept notwendig.

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

Kontrastmittelverstärkte 3D-MR-Perfusion der Lunge: Einsatz paralleler Bildgebungstechniken bei gesunden Probanden

PURPOSE Evaluation of lung perfusion by contrast-enhanced 3D MRI using partial parallel imaging techniques. MATERIALS AND METHODS Eight healthy volunteers were examined using a contrast-enhanced dynamic FLASH 3D sequence with partial parallel imaging technique at 1.5 T MRI with a TA of 1.5 sec. The whole lung was covered by 36 coronal slices. A ventral, middle and dorsal slice of each lung was manually segmented and signal-to-time curves were computed. For absolute quantification of blood flow through the right and left pulmonary artery, phase-contrast flow measurements were performed. RESULTS No significant difference was found between the signal intensity in the right (8.9 +/- 2.6) and le…

Assessment of Thoracic Aortic Dimensions in an Experimental Setting: Comparison of Different Unenhanced Magnetic Resonance Angiography Techniques With Electrocardiogram-Gated Computed Tomography Angiography for Possible Application in the Pediatric Population

PURPOSE To compare different unenhanced magnetic resonance angiography (MRA) techniques for quantitative evaluation of vessel lumen in an experimental setting in young pigs whose dimensions allow for a comparison with a pediatric population. MATERIAL AND METHODS Magnetic resonance imaging was performed in 5 healthy ventilated pigs at 1.5 T. Three different electrocardiogram (ECG)-triggered sequences were applied for MRA: [TSE-Db] T2-weighted dark-blood TurboSpinEcho (2.0 x 1.1 x 4 mm3); [trueFISP] 2D-steady-state-free-precession (2.2 x 1.8 x 2 mm3); [NAV] respiratory-gated, T2-prepared 3D-trueFISP (1.3 x 1.3 x 1.3 mm3). ECG-gated-CT angiography (CTA) (16-row CT, 1 mm collimation) served as …

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…

Niederfeld-MR-Tomographie des Kniegelenkes: Ergebnisse einer prospektiven, arthroskopisch kontrollierten Studie

PURPOSE To define the diagnostic accuracy of an open low-field MR unit (Magnetom Open, Siemens, Erlangen) in traumatic knee lesions. MATERIALS AND METHODS The MRIs of 150 patients were prospectively evaluated by two independent readers with different experience levels. The study protocol included a proton-density weighted SE-sequence in the sagittal, a T2.-weighted Flash-2D-sequence in the coronal, and a 3D-acquisition (DESS) in the axial plane. 75 patients were treated either conservatively or operatively. RESULTS Based on arthroscopy as the gold standard, the sensitivities, specificities, and diagnostic accuracies for lesions of the medial and lateral meniscus, the anterior cruciate ligam…

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…