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…

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 …

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…

Ein Auswerteprogramm zur quantitativen Untersuchung der Lungenventilation mittels dynamischer MRT von hochpolarisiertem 3He

Purpose: 3 He-MRI is able to visualize the regional distribution of lung ventilation with a temporal and spatial resolution so far unmatched by any other technique. The aim of the study was the development of a new software tool for quantification of dynamic ventilation parameters in absolute physical units. Materials and Methods: During continuous breathing, a bolus of hyperpolarized 3 He (300 ml) was applied at inspiration and a series of 168 coronal projection images simultaneously acquired using a 2D FLASH-sequence. Postprocessing software was developed to analyze the 3 He distribution in the lung. After correction for lung motion, several ventilation parameters (rise time, delay time, …

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 …

Lung density distribution in dynamic CT correlates with oxygenation during pressure-controlled ventilation of pigs with lavage-ARDS

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…

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…

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…

Reformatierungen als Lösungsansatz für die Problematik der unterschiedlichen Schichtführung beim Vergleich von3He-MRT und HR-CT der Lunge

Purpose: 3 He-MRI of the lung has been shown to be a sensitive method for functional imaging of the lung. A previous study compared 3 He-MRI (coronal planes) with CT (transverse planes) by looking for ventilation defects and their pathomorphologic correlation. Anatomic structures, such as lobar fissures and hilar vessels, were used for orientation, but the reliable assignment of ventilation defects to lung segments is problematic. The present work compares multiplanar reformations of 3 He-MRI and HR-CT, which were generated from planes determined by the respective method, and investigates their suitability as a solution of this problem. Materials and Methods: A total of 16 data sets taken f…

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…

SPLIT-LUNG VOLUMETRY IN PATIENTS AFTER SINGLE-LUNG TRANSPLANTATION USING 3HELIUM-MRI 

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…

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 …

Prospektive Machbarkeitsstudie zum Vergleich von Röntgenübersichtsaufnahme und Thorax-MRT in Atemanhaltetechnik am offenen Niederfeldgerät

PURPOSE MR investigations using a breath-hold sequence at an open low-field MR had to be compared to chest X-rays in patients with a wide spectrum of cardio-thoracic pathologies. MATERIAL AND METHODS 114 patients and three volunteers who actually received a chest X-ray due to different indications underwent triplanar breath-hold (17 - 20 s) True-FISP sequence using a 0.2 T low-field MR (Siemens Magnetom Open, TR/TE/alpha: 7.3/3.5/80 degrees, SD: 10 mm, Pixel: 2.81 x 1.41 mm) a mean of 5.1 (+/- 8.2) days later. RESULTS Signal-to-noise ratio as basics for pattern recognition was 3.2 in nodule, 5.0 in infiltration, and 12.0 in effusion, and therefore True-FISP is usable for the detection of th…

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…

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…

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…

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…

Hochauflösende Computertomographie der Lunge bei neutropenischen Patienten mit Fieber

Purpose To determine the sensitivity and clinical impact of high-resolution CT (HRCT) of the lung in febrile neutropenic patients under antibiotic therapy. Material and methods Chest X-ray and HRCT were prospectively performed to exclude pneumonia in 34 patients (53 examinations) suffering from febrile neutropenia following antitumor therapy. Diagnosis was confirmed by bronchoalveolar lavage or sputum cultures. Results Chest X-ray showed pneumonia in 13/53 examinations, in 12/13 a micro-organism was found. HRCT demonstrated pneumonia in 39/53, in 31/39 a micro-organism was found. All cases with positive cultures showed suspicious HRCT findings. Changes in antibiotic treatment resulted in fi…

Fokussuche bei neutro- penischem Fieber

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 …

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-…

Computertomographische Funktionsuntersuchung der Lunge nach einseitiger Lungentransplantation mit axialer und koronarer Akquisition

After single-lung transplantation in a patient suffering from obstructive emphysema lung function parameters worsened during follow-up. To complement the routine high-resolution CT (HRCT) scans acquired in inspiration, additional scans were obtained to evaluate regional lung function. The comparison of HRCT scans acquired in inspiration and in expiration revealed different ventilation conditions of both lungs, continuous acquisition in a single slice (dynamic multiscan acquisition) in the axial and coronal plane demonstrated mediastinal shifting and the movement of the diaphragm during the whole breathing cycle. Both modalities can provide important information concerning regional differenc…

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…

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 …

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 …

Spiral-CT und 3 D-Rekonstruktion des Tracheobronchialbaumes zur Auswahl geeigneter Doppellumentuben vor Einzellungenbeatmung

Purpose To assess the potential of 3-D spiral CT in the selection of adequate double-lumen tubes (DLT) for one-lung-ventilation. Materials and methods 3-D spiral CT of eight different DLTs was performed with standardized acquisition parameters: section thickness 4 mm, table speed 6 mm/s, increment 3 mm and standardised thresholds, window settings and magnification zoom. The accuracy was confirmed by measuring 3-D objects on screen and original DLTs by vernier caliper. 3-D spiral CT was performed in 20 patients preoperatively with slice thickness 4-8 mm, pitch 1-1.5, increment 4-8 mm. To select the adequate DLT size the 3-D reconstructions of the patient's tracheobronchial tree and of the DL…

Ein Auswerteprogramm zur quantitativen Analyse von Messungen des alveolären Sauerstoffpartialdrucks (pAO2) mit der sauerstoffsensitiven 3He-MR-Tomographie

Purpose: To develop a software tool for quantitative analysis of alveolar oxygen partial pressure (p A O 2 ) as well as its time course during apnea. Material and Methods: T 1 -relaxation times of hyperpolarized 3 He are reduced by paramagnetic oxygen rendering 3 He-MRI sensitive to oxygen and thus allowing the assessment of the local oxygen partial pressure in the pulmonary airspaces. Oxygen-related relaxation and loss of polarization by RF-excitation can be discriminated by acquiring two image series with varying interscan delay and/or flip angles. Software was developed to calculate the p A O 2 and the decay rate in user-defined regions of interest (ROIs) automatically. Moreover, paramet…

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:…

Analysis of the intrapulmonary distribution of ventilation and PO2 in patients after single-lung transplantation: a 3Helium MRI study

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 …

Funktionelle Bildgebung der Lunge mit gasförmigem Kontrastmittel: ³Helium-Magnetresonanztomographie

Current imaging methods of the lung concentrate on morphology as well as on the depiction of the pulmonary parenchyma. The need of an advanced and more subtle imaging technology compared to conventional radiography is met by computed topography as the method of choice. Nevertheless, computed tomography yields very limited functional information. This is to be derived from arterial blood gas analysis, spirometry and body plethysmography. These methods, however, lack the scope for regional allocation of any pathology. Magnetic resonance imaging of the lung has been advanced by the use of hyperpolarised (3)Helium as an inhaled gaseous contrast agent. The inhalation of the gas provides function…

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 …

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 …

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…

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…

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…

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 …

[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…

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…

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…

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…

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…

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…

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…