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Purpose: To show the feasibility of a stress magnetic resonance imaging (MRI) as a new method for simultaneous evaluation of the morphology and the functional integrity of the acromioclavicular joint (ACJ) ligamentous stabilizers. Materials and Methods: MRI of four volunteers, 10 patients with acute, and six with chronic ACJ injuries was performed using a 0.25 T open MRI scanner. A 2D-proton-density and a 3D-gradient-echo sequence at rest and under 6.5 kg shoulder traction were performed. Comparative measurements of the coracoclavicular and the acromioclavicular distance were performed. Additionally, the conoid and trapezoid ligament lengths were measured with multiplanar reconstructions. Results: MRI at rest correctly identified tears of the coracoclavicular and the acromioclavicular ligaments in eight patients suffering acute ACJ injuries. Stress application helped to distinguish between partial and complete coracoclavicular ligament tears in two cases. Insufficiency of the ACJ ligaments was present in all acute and chronic ACJ injuries. Stress application in chronic ACJ ligaments revealed isolated insufficiency of the conoid ligament in three cases and of the trapezoid ligament in one case. Combined insufficiency was present in two cases. Conclusion: Stress MRI facilitates simultaneous acquisition of morphologic and functional information of the ACJ stabilizers. In acute ACJ injuries it helps to distinguish between partial and complete ligament tears. In chronic ACJ injuries it provides functional information of the ligament regrinds. J. Magn. Reson. Imaging 2013;37:1486–1492. © 2012 Wiley Periodicals, Inc.

To evaluate the image quality of time-resolved contrast-enhanced MRA (tr-MRA) employing echo-sharing with stochastic trajectories for the bilateral examination of the hands.In this institutional review-board approved study, Tr-MRA was compared with multiphasic contrast-enhanced MRA (mp-MRA) featuring sub-systolic venous compression in 20 healthy volunteers at 3.0 T using the following settings: TR/TE: 2.8/1.2 ms, flip angle: 25°, acceleration factor: 4, effective voxel size: 0.9 × 0.8 × 0.9 cm, acquisition time 4.9 s per 3D volume.With tr-MRA the arterial first-pass contrast agent transit is clearly seen. On average the contrast agent arrived 34 s post-injection and reached the proper digital arteries after 44 s. The mean arterio-venous window was 13 s. Bilateral contrast enhancement was asynchronous in 56-62%. On a semiquantitative scale (0 = non-sufficient to 4 = excellent) tr-MRA (mp-MRA) yielded an average ranking of 2.8-3.6 (3.1-3.8) in the greater and intermediate sized segments and 1.3-2.0 (1.6-2.3) in the proper digital arteries.Compared with established multiphasic ce-MRA, time-resolved MRA allows a four times faster acquisition. It reflects the natural haemodynamics of the hand arteries with no need for sub-systolic venous compression and may be beneficial in the detection of hand circulation disorders. Image quality is comparable to mp-MRA. In both techniques depiction of the proper digital arteries is limited.

To prospectively investigate the feasibility, image quality, and radiation dose for prospective electrocardiographically (ECG) triggered sequential dual-source computed tomographic (CT) angiography of the thoracic aorta in comparison to retrospective ECG-gated helical dual-source CT angiography.This study was approved by the institutional review board; informed consent was obtained. One hundred thirty-nine patients referred for ECG-assisted dual-source CT angiography of the thoracic aorta were prospectively enrolled. Inclusion criteria were stable sinus rhythm and heart rate of 80 beats per minute or less. Tube voltage was adjusted to body mass index (25.0 kg/m(2), 100 kV, n = 58;or = 25.0 kg/m(2), 120 kV, n = 81). In both cohorts, patients were randomly assigned to prospective or retrospective ECG-assisted data acquisition. In both groups, tube current (250 mAs per rotation) was centered at 70% of the R-R cycle. The presence of motion or stair-step artifacts of the thoracic aorta was independently assessed by two readers. Effective radiation dose was calculated from the dose-length product.Subjective scoring of motion and stair-step artifacts was equivalent for both techniques. Scan length was not significantly different (23.8 cm +/- 2.4 [standard deviation] vs 23.7 cm +/- 2.5 for prospective and retrospective ECG-triggered CT angiography, respectively; P = .54). Scanning time was significantly longer for prospective ECG-triggered CT angiography (18.8 seconds +/- 3.4 vs 16.4 seconds +/- 3.3, P.001). Mean estimated effective dose was significantly lower for prospective data acquisition (100 kV, 1.9 mSv +/- 0.5 vs 4.1 mSv +/- 0.7, P.001; 120 kV, 5.3 mSv +/- 1.1 vs 9.5 mSv +/- 3.0, P.001).Prospective ECG-gated sequential dual-source CT angiography of the thoracic aorta is feasible, despite the slightly longer acquisition time. Thus, motion-free imaging of the thoracic aorta is possible at significantly lower radiation exposure than retrospective ECG-gated helical dual-source CT angiography in certain patients with a regular heart rate.

Purpose To qualitatively and quantitatively evaluate the image quality in accelerated time-resolved 3D contrast-enhanced MR angiography (tr-CE-MRA) at 3T. Materials and Methods In all, 113 MRA were performed in 107 patients on a 3T MR system after written informed consent and approval by the ethics committee. Twenty consecutive thoracic (n = 87) or craniocervical (n = 26) 3D data volumes were acquired. The timeframes with maximum arterial and venous contrast were determined and a total of 663 arterial and venous segments were analyzed by two blinded observers. Diagnostic image quality was graded by applying a 0 (low) to 3 (excellent) scale. Additionally, local signal-to-noise (SNR) and contrast-to-noise ratios (relative CNR) were evaluated. Results Tr-CE-MRA was successfully performed in all patients. Good to excellent image quality (2.42 ± 0.31) was observed in all individuals with preserved discrimination of arteries (2.43 ± 0.48) and veins (2.20 ± 0.56). Minor image degradation due to artifacts (2.62 ± 0.25) and constantly high vascular signal and contrast were detected. There was a significant superiority of coronal orientation during thoracic MRA (P < 0.05). In 18 cases tr-CE-MRA provided additional information on vascular pathologies. Conclusion Large field of view tr-CE-MRA enables constantly high-quality thoracic and craniocervical angiographies. In addition, the dynamics of tr-CE-MRA can offer additional information on vascular pathologies. J. Magn. Reson. Imaging 2008;28:1116–1124. © 2008 Wiley-Liss, Inc.

PURPOSE The objective of this study was to compare the diagnostic value of cinematic magnetic resonance imaging with static MRI examinations in patients with rheumatoid arthritis and concomitant attack of the cervical spine. METHODS Dynamic functional MRI examinations of the cervical spine were performed one five subjects without complaints and 20 patients with rheumatoid arthritis. For the functional studies, a positioning frame was used that allowed infinitely variable forward and backward inclinations of the head. RESULTS Functional magnetic resonance imaging made possible a sufficiently good differentiation of the extension of pannus tissue cranial, ventral, and dorsal of the dens with possible displacing and impinging effects on the spinal cord during flexing and stretching movements. In addition, it is suitable for demonstration of the degree of instability in the atlanto-occipital and atlanto-axial planes. In contrast to conventional X-rays, CT, and static MRI, basilary impression as well as compressions and angulations of the cervical bone marrow are better visualized by cinematic magnetic resonance tomography. CONCLUSIONS Functional magnetic resonance tomography is an important diagnostic method for the induction of the cervical spine in patients with rheumatoid arthritis. In particular, fusion and instabilities as well as compressions of the bone marrow often can only be detected with the help of functional MRI.

The purpose of this study was to determine the benefit of bilateral contrast-enhanced MR angiography (ce-MRA) of the hands at 3.0 Tesla (T) compared with an established 1.5-T technique in healthy volunteers. Intraindividual bilateral ce-MRA of the hands was performed at 1.5 T and 3.0 T in 14 healthy volunteers using a timed ultra-fast GRE sequence featuring parallel acquisition. The evaluation comprised measurement of the vessel signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), rating of the image quality and the assessment of artefacts and venous contamination. At 3.0 T, SNR improved up to 95% and CNR up to 129%. The image quality of the larger inflow arteries, the palm arches and common digital arteries was good or sufficient at either magnetic field strengths. However, 3.0-T MRA was clearly superior in the depiction of the digital arteries. Ce-MRA of the hand clearly profits from the use of 3.0 T. Compared with 1.5 T, a substantial increase of CNR is found resulting in a significantly better delineation of the small digital arteries. Saturation affects more the SNR of the perivascular tissue than the contrast-enhanced blood, and thus leads to a marked increase of CNR at 3.0.

In large installations of a Picture Archiving and Communication System (PACS), data protection becomes an issue. Above all, not every employee should have access to all data stored in the system. At the Freiburg University Hospital, we developed a concept of dynamic assignment of authorization, assuring that every physician is authorized to the data of all patients under his care. We describe the technical implementation of data protection developed for the integration of PACS and electronic patient records in Freiburg. The system was installed in January 2001 and the experience of its two years in operation is reported.

Purpose: To develop and evaluate non-slab-selective magnetization preparation in contrast-enhanced 3D-MR angiography. Methods: An ultrafast spoiled mr angiography sequence (FLASH) with non-selective inversion prepulses for background suppression was implemented on a 1.5 T MR system. In 11 patients gadobenate dimeglumine-enhanced mr-angiography of the pelvic and lower leg arteries was performed using the AngioSURF device. Source data was evaluated for contrast-to-noise-ratio, image quality and the extent of background suppression. Results: Background suppression and selective vessel contrast was excellent in all vascular levels. The mr protocol was comfortable and easy-to-handle. Abandonment of precontrast-series acquisition simplified the examination procedure markedly. Conclusions: Magnetization preparation provides efficient suppression of the background signal in contrast-enhanced 3D mr angiography of the pelvic and lower leg arteries. Since no subtraction technique is needed, moving-bed and whole body MRA-protocols can be simplified significantly.

Internal pancreatic fistulas are uncommon but well-recognized complications of inflammatory pancreatic disease. A case of a pancreatico-mediastinal fistula with a mediastinal mass lesion in a patient with a documented history of chronic alcohol consumption and previous episodes of acute pancreatitis is described. Since the clinical symptomatology was dominated by pulmonary complaints, magnetic resonance (MR) imaging using a breathhold coronal T2-weighted sequence with spectral fat saturation was essential in clarifying this difficult and rare pathology. Furthermore, the depiction of a fistulous tract between a mediastinal mass lesion and the retroperitoneum posterior to the pancreas, i.e., a pancreatico-mediastinal fistula by MR imaging has not been previously reported, to the best of our knowledge. J. Magn. Reson. Imaging 2002;16:746–750. © 2002 Wiley-Liss, Inc.

Indirect Magnetic Resonance Fistulography: A New Gold Standard in Diagnosing Perianal Fistulas? Comparative Studies Purpose: The aim of this prospective study

rationale and objectives. To assess the suitability of contrast-enhanced magnetic resonance angiography (MRA) in the preoperative evaluation of hand vasculature in potential candidates for radial artery bypass grafting. methods. In 21 patients, gadobenate dimeglumine-enhanced, three-dimensional gradient-echo sequences of both hands were performed, as well as a Doppler ultrasound study with radial artery compression. Doppler findings were correlated with MRA, focusing on the assessment of anastomoses between the vascular bed of the ulnar and radial arteries. results. One individual had to be excluded because of accidentally disclosed metal foreign bodies. Sufficient depiction of the hand vasculature was achieved in the remainder. Seventeen patients had evidence of adequate collateral flow between the ulnar and radial artery supply on Doppler ultrasound. Three patients exhibited inadequate collateral flow, with angiographic signs of vessel occlusion or missing collaterals between the palmar arches. Two patients presented with stenosis or occlusion of the radial artery. Magnetic resonance angiograms displayed great variations in hand vasculature and collateral formation, with no mismatch compared with Doppler ultrasound results. conclusions. Contrast-enhanced MRA displays vascularization of the hand in detail and supplies ultrasound flow measurements for radial artery harvest, with high-resolution angiographic data about possible vessel variations and the presence of anastomoses between the radial or ulnar artery supply.

Purpose: In our patient study, we examined the clinical usefulness of phase contrast velocity mapping for the detection and characterization of localized abnormalities of left ventricular motion. Materials and Methods: Velocity encoding is based on the fact that motion in the presence of a magnetic field gradient causes a change of the phase of the MRI signal that is proportional to the velocity of tissue motion. Left ventricular motion was characterized by parameters describing rotation and contraction/dilatation, respectively. We examined 34 patients with localized abnormalities of left ventricular motion due to ischemic heart disease. Results: Three patients could not be sufficiently evaluated due to technical problems including varying positions of the heart during successive breathhold periods. In 27 of the remaining 31 patients, MRI could demonstrate abnormal radial velocities that corresponded fully or partly with perfusion deficits in single photon emission computed tomography or positron emission tomography. The abnormalities were most pronounced in early diastole. Rotational velocities did not show any regional changes. Conclusion: Our study showed that our technique is suitable for the detection and characterization of localized abnormalities of left ventricular motion in patients with ischemic heart disease.

Phaeochromocytomas are rare, mostly benign neuroendocrine tumours of the medulla of the adrenal glands that present as sporadic tumours or as manifestations of hereditary syndromes such as von Hippel–Lindau disease.1 Symptoms are mostly unspecific; occasionally the triad of headache, sweating and palpitations2 is found. Conversely, phaeochromocytomas can present acutely with malignant hypertension and varying clinical features ranging from rhabdomyolysis and myoglobinuric renal failure to haemorrhagic necrosis, pulmonary oedema3 and cardiogenic shock.4 Phaeochromocytomas with malignant hypertension frequently show a fatal clinical course, particularly when microangiopathic haemolytic anaemia is present. A 28-year-old Caucasian woman presented with somnolence, diffuse abdominal pain, emesis, epistaxis, petaechiae and oliguria. She reported weight loss of 13 kg within a few weeks, palpitations, tremor, sweating and blurry vision. Her past medical history was unremarkable; she denied any history of hypertension. Her only medication were contraceptive pills. She had no relevant family history. Physical examination showed a somnolent patient with a blood pressure of 230/140 mmHg and a heart rate of 100 bpm. Her extremities showed extensive petechiae. The upper abdomen was tender without rigidity. The neurological examination was without focal deficit. Funduscopy showed cotton wool spots and striate haemorrhages but no papillary oedema. She had anaemia (haemoglobin 8.3 g/dl) and thrombocytopenia (76 000/mm3). Acute renal failure was present (creatinine 6.0 mg/dl). Microscopic examination of the urine revealed red cell casts. The urine protein:creatinine ratio was 8.3. Doppler …

phy in Comparison with DSA and Urography. Purpose: To assess a contrast-enhanced standardized MRA protocol for the presurgical evaluation of potential renal transplant donors. Methods: Twenty-three potential donors for renal transplantations were examined with gadolinium-enhanced, two-phase MR angiograms (1.5T) and DSA/urography for the number of renal arteries, the presence of aberrant arterial and venous branches, renal artery stenoses and anatomy of the renal collecting system and ureters. The diagnostic value was assessed by evaluating different image processing modalities and inter-observer variability. Results: Using maximum intensity projections (MIP) together with multiplanar reformatting (MPR), accessory arteries were detected with a sensitivity/specificity of 100%/98%. Depending on diagnostic experience, exclusive evaluation of MIP yielded a sensitivity/specificity of 67-100%) 95-100%. Using MIP/MPR, venous depiction was good in 80%, with MIP solely in 30-40%. At least the proximal third of the ureter was visible in 67%. Conclusion: MPR/MIP evaluation of two-phase, contrast-enhanced MRA provides an excellent depiction of renal vessel anatomy for presurgical evaluation of renal transplant donors. Exclusive MIP assessment is less reliable and depends strongly on the examiner's experience. For sufficient visualization of the ureters, either additional measurements or low-dose diuretic injection have to performed.

Objective : to evaluate the influence of different spiral CT examination protocols suitable for clinical use on image quality and to assess the observer dependence in interactive real-time virtual bronchoscopy. Methods and patients : real-time perspective volume rendering of the airways in twenty normal patients based on four different spiral CT examination protocols was evaluated by four observers in regard to the order of depictable bronchi. Results : best results were obtained using an examination protocol with a small beam collimation and a maximum pitch. Depending on the observer’s ability to control the fly path and the orientation of the bronchi with respect to the slice plane up to sixth order bronchi could be depicted. Inter-observer variability was up to two branching orders. Conclusion : The performance of virtual bronchoscopy strongly depends on the applied CT examination protocol and the observers experience with perspective volume rendering. Both of which have to be taken into account when virtual bronchoscopy is compared with fiberoptic bronchoscopy.

Purpose: The purpose of this work was to evaluate the feasibility and clinical use of MR angiography (MRA) for examining the pelvic and lower limb arteries in patients with arterial occlusive disease. Method: Seventy-six patients with clinical signs of peripheral arterial occlusive disease were included in the study. MRA was performed using a fast contrast-enhanced high-resolution 3D technique that covered the area from the distal abdominal aorta to the distal lower limbs in two examination steps. Results: In all patients, diagnostic images comparable with those of conventional intraarterial digital subtraction angiography (DSA) could be obtained. No false-negative findings were seen in the iliac, femoral, or popliteal arteries. Ten to 16% of the mild stenoses and 6-14% of the severe stenoses, mainly in the crural vessels, were overgraded compared with intraarterial DSA. Particularly in patients with proximal severe obstructions or occlusions, the crural segments could be depicted more clearly due to decreased arterial runoff in conventional angiography. Conclusion: The consistency of the excellent depiction of the vascular territories of the distal aorta and the pelvic and lower limb arteries in a standardized setting suggests great potential for the use of MRA in the primary diagnosis of peripheral arterial occlusive disease.

A number of methods have been proposed for the noninvasive measurement of myocardial wall motion. The paper describes a strategy for assessing myocardial motion based on the sensitivity of the phase of the MR-signal to motion using a breath-hold phase contrast technique. A motion-sensitized and a motion-compensated MR-signal are measured during successive scans. The difference between the two MR-signals is used to calculate myocardial velocity in all three spatial dimensions. Postprocessing includes the transformation of the measured velocities into an internal coordinate system of the left ventricle. Also various presentation modes and further processing of the received velocity information are provided including calculation of global motion parameters. We examined 20 patients suffering from myocardial infarction. The overall left ventricular motion can be characterized by appropriate parameters describing the rotation and contraction or expansion, respectively. Regional motional disturbances are visualized using parametric images. Contrary to the highly consistent interindividual data in normal volunteers, patients showed significant localized motion deficits.

Raynaud's disease is associated with disorders in blood circulation of the hands. The gold standard to visualise pathology of digital arteries is catheter angiography. Contrast-enhanced MR angiography (CE MRA) has developed even more as an alternative non-invasive method to digital subtraction angiography, mostly for pelvic or lower limb vessels. We report a case of primary Raynaud's disease with high-grade stenosis and an occlusion of the digital arteries. This case illustrates the benefit and efficiency of CE MRA at high fields in depicting location and extension of peripheral arterial alterations.

Background: Anatomic reconstruction of the coracoclavicular ligaments for the treatment of acromioclavicular joint separations provides superior biomechanical stability compared with other procedures. Clavicular and coracoidal footprints of the conoid ligament (CL) and the trapezoid ligament (TL) are well described. So far, little is known about their kinematics and the changes of the coracoclavicular distance during shoulder abduction. Hypothesis: The coracoclavicular distance along the coracoclavicular ligaments changes significantly with shoulder abduction and weightbearing. Study Design: Descriptive laboratory study. Methods: With use of an open magnetic resonance imaging scanner, the shoulders of 13 healthy volunteers were examined in supine and sitting positions. Three-dimensional magnetic resonance images of the shoulders were obtained in 30° increments of abduction (0°-120°). A manual segmentation of the scapula, the clavicle, and the coracoclavicular ligaments was performed. The insertion points of the coracoclavicular ligaments were identified, and automated measures along the ligamentous course were carried out. Results: During transfer from the lying to sitting position, the coracoclavicular distance showed significant lengthening of 3 mm along the center of the CL, which significantly increased another 3 mm during shoulder abduction to a total lengthening of 6 mm. In the supine position, the coracoclavicular distance along the TL did not elongate significantly. In the sitting position, the distance along the medial portion of the TL shortened significantly, whereas the distance along the center portion did not elongate significantly during shoulder abduction. Conclusion: The distances between the coracoclavicular insertion points depend on both patient and shoulder positioning. To prevent overconstraining of the graft, the CL should be fixated during 90° to 120° of shoulder abduction in a sitting position. Isometric reconstruction of the TL can be achieved if precise fixation of the graft at the centers of the conoidal and clavicular footprints is performed.

Purpose To demonstrate the feasibility of time-resolved 3D MR velocity mapping at 3 Tesla for the visualization of vascular hemodynamics in normal iliac and femoral arteries. Materials and Methods Electrocardiographically (ECG) synchronized three-dimensional (3D) CINE phase-contrast MRI with three-directional flow encoding was adapted to analyze flow in peripheral arteries at 3T. Visualization of peripheral arterial hemodynamics within the acquired data volume included 3D streamlines and time-resolved 3D particle traces within the major vessels and localized analysis of flow profiles using 2D-vector graphs. Data was visually compared to results from color-coded duplex ultrasound (US). Results Global and detailed local blood flow characteristics were successfully analyzed in all subjects. In agreement with US findings, normal laminar flow patterns without flow acceleration or disturbances were visualized in all healthy individuals. In an exemplary patient measurement multiple segmental flow accelerations could be demonstrated. MRI additionally revealed complex helical flow alterations distal to a moderate stenosis. Conclusion Due to the full spatial and temporal coverage of the arteries of interest, 3D CINE phase contrast MRI at 3T is a promising tool for the evaluation of vascular hemodynamics in peripheral arteries. Future methodological improvements will be directed to improve spatial and temporal resolution as well as quantitative data analysis. Moreover, the technique will have to be evaluated in patients in comparison to standard diagnostic tools. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc.

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 (NPV) for detection of relevant stenosis (>50%) were calculated for the right and left internal carotid arteries, and common and external iliac arteries: Sensitivity was 95–98% (onsite) and 76–96% (BR), specificity 94–96% (onsite) and 86–94% (BR), accuracy 96% (onsite) and 87–93% (BR), NPV 98–99% (onsite) and 84–98% (BR), and PPV 79–93% (onsite) and 44–91% (BR), respectively. Conclusion CeMRA of body arteries using 1.0 M gadobutrol provides diagnostic information comparable to intraarterial DSA.

To evaluate whether time-resolved 3D MR-angiography at 3T with a net acceleration factor of eight is applicable in clinical routine and to evaluate whether good image quality and a low artifact level can be achieved with a temporal update rate that allows for additional information on pathologies.Thirty-one consecutive patients underwent time-resolved 3D contrast-enhanced MR-angiography on a 3T system. Imaging consisted of accelerated 3D gradient echo sequences combining parallel imaging with an acceleration factor of four, partial Fourier acquisition along phase and slice encoding direction, and twofold temporal acceleration using view sharing. Data volumes representing the arterial and venous contrast phases were independently evaluated by two experienced radiologists by grading of image quality and artifact level on a 0-3 scale.Time-resolved MR-angiography was successfully performed in all subjects without the need for contrast agent bolus timing. Excellent arterial (average score = 2.65 +/- 0.32) and good venous (average score = 2.56 +/- 0.28) diagnostic image quality and little image degrading due to artifacts (average score = 2.20 +/- 0.16) were confirmed by both independent readers (agreement in 65.2% of all evaluations). In 14 patients vascular pathologies were identified in the arterial phases. In eight examinations temporal resolution and depiction of contrast agent dynamics provided additional information about pathology.Without the necessity for additional bolus timing, time-resolved 3D contrast-enhanced MR-angiography with imaging acceleration along both the spatial encoding direction and temporal domain revealed excellent diagnostic image quality in neurovascular and thoracic imaging. Despite the limited spatial resolution as compared to high-resolution imaging of the carotid artery bifurcation, the results demonstrate the applicability of contrast-enhanced MR-angiography in thoracic and abdominal MRA as well as cervical imaging with a temporal update rate allowing for additional information on pathologies. Future studies may include an evaluation of optimal trade-offs between spatial and temporal resolution, different acceleration factors and a comparison to the gold-standard for accuracy.

MDCT is a rapidly evolving technique that significantly improves CT imaging for several indications including depiction of focal benign lesions. Imaging mainly profits from improved longitudinal spatial resolution allowing high-quality non-axial reformations and 3D reconstructions and CT angiography as well as rapid accurate multiphase imaging with short breath-holding periods. This review provides an overview of the current status of MDCT with respect to liver imaging and the implications for characterizing benign focal liver lesions. MDCT currently allows the acquisition of thin slices in daily routine diagnostics providing an improved detection rate of small liver lesions. Whereas large benign focal liver lesions exhibit typical patterns of morphology, attenuation and perfusion, which also may be assessed with single-slice scanners, small lesions remain challenging even with MDCT, since the specific criteria for confident diagnosis become more ambiguous. Here, MR imaging provides more detailed information about tissue components and the availability of liver-specific contrast agents, adding further impact to this technique. With respect to dose considerations, the number of necessary multiphase scans as well as the application of very thin collimation should be strictly checked for each patient undergoing MDCT based on the individual clinical situation and question.

Vergleich des diagnostischen Stellenwerts der Ganzkorper-MRT (GK-MRT) als neues und schnelles Untersuchungsverfahren vs. Skelettszintigraphie (SKZ) bei der Erkennung ossarer Metastasen solider Tumoren. Bei 129 Patienten mit soliden Malignomen wurde eine GK-MRT im intraindividuellen Vergleich mit der SKZ durchgefuhrt. Zum Einsatz kamen der innovative Angio-SURF®-Rolltisch mit integrierter Phased-array-Oberflachenspule und koronare TIRM-Sequenzen fur verschiedene Korperregionen. In 81% der Falle lagen konkordante Befunde bei GK-MRT und SKZ vor, wobei in 43% beide Verfahren Skelettmetastasen ausschlossen. Bei 38% zeigten GK-MRT und SKZ Skelettmetastasen, wobei in 45% die GK-MRT ausgedehntere Befunde nachwies. Bei 12% war die SKZ der GK-MRT uberlegen, bei 19% lagen diskordante Befunde vor, wobei die GK-MRT in 15 Fallen Skelettmetastasen bei negativer SKZ detektierte. In 9 Fallen war die SKZ positiv bei negativer GK-MRT. In 60% der Falle wurden mit der GK-MRT tumorassozierte Befunde erhoben. Die GK-MRT stellt fur die Detektion ossarer Metastasen ein vielversprechendes neues Stagingverfahren dar, welches in vielen Fallen sensitiver als die Skelettszintigraphie bzgl. des Nachweises und der Ausdehnung von Skelettmetastasen und therapeutisch relevanter Befunde ist.

A major consideration in the reduction of early stent thrombosis and in-stent restenosis is the improvement of biocompatibility of the devices. Diamond-like carbon is a novel material for coating stent surfaces in order to increase biocompatibility. The authors report on the endovascular treatment of two individuals with superficial femoral artery occlusions, using stents coated with diamond-like carbon. Technical and clinical success was achieved in both cases, with primary patency rates of 100% 12 months after intervention.

Ziele: Evaluation des Stellenwerts der Multislice CT in der Detektion und praoperativen und postoperativen Evaluation von Calcaneusfrakturen Methode: Uber einen Zeitraum von 12 Monaten wurden aufeinanderfolgend 56 Multisclice CT-Untersuchungen (46 praop Untersuchungen. 10 postop Untersuchungen) (Somatom Volume Zoom, Siemens) bei 50 Patienten zur Erkennung, Ausmasbestimmung oder postoperativen Verlaufskontrolle von Calcaneusfrakturen durchgefuhrt. Aufgrund chirurgischer Interventionen oder Patientenimmobilitat konnte nur selten die angestrebte axiale Schichtung durchgefuhrt werden. 2D Rekonstruktionen wurden standardisiert mit den folgenden Parametern durchgefuhrt: 2mm Schichtdicke, 1mm Kollimation, 2 Inkrement, 0,5 s Rotationszeit. Alle Untersuchungen wurden von zwei erfahrenen Radiologen im Hinblick auf das Vorliegen einer Calcaneusfraktur und einer Beteiligung des Talocalcaneargelenks ausgewertet Ergebnis: Mit der Multislice CT wurden 21 unilaterale sowie 5 bilaterale Calcaneusfrakturen diagnostiziert. In 20 Fallen konnte eine Fraktur ausgeschlossen werden. Routinemasig erstellte multiplanare Rekonstruktionen zeigten Frakturen der anterioren (48%), mittleren (45%) und posterioren (61%) Facette des Talocalcaneargelenks. 65% der Frakturen betrafen das calcaneocuboidale Gelenk. Schlussfolgerung: Die Spiral-CT ist die Methode der Wahl in der Diagnose von Calcaneusfrakturen. Es ist das einzige bildgebende Verfahren, dass hinreichende Informationen uber knocherne Strukturen und uber eine mogliche Gelenkbeteiligung vor chirurgischer Rekonstruktion liefert. Daruber hinaus reduziert die Multislice CT die Untersuchungszeit und bietet isotrope, multiplanare, qualitativ hochwertige Bildgebung unabhangig von der Lagerungsposition des Patientenfuses.

The aim of this study was to demonstrate and measure perfusion deficits caused by central bronchogenic carcinoma and to compare magnetic resonance angiography (MRA) perfusion data with data of perfusion scintigraphy. The diagnostic value of 2D MRA in detection of malignant pulmonary artery stenosis in comparison with conventional DSA was investigated.Eighteen patients were included in the study. MRA, conventional pulmonary angiograms, and pulmonary perfusion scintigrams were performed. MRA and DSA were compared and MR pulmonary perfusion data were assessed and compared with scintigraphical data.Perfusion defect could be demonstrated and localized in all patients. A quantitative perfusion deficit and a side dependent perfusion ratio could be evaluated. There was statistically significant correlation between MR perfusion and scintigraphically acquired data. 2D MRA showed a high correlation for detection and grading of stenosis compared with angiograms.Pulmonary perfusion could be demonstrated by using an ultrafast 2D projection MR DSA sequence. This technique allows measurement and quantification of pulmonary perfusion abnormalities in patients with malignant stenosis with statistically significant correlation to perfusion scintigraphy. The diagnostic potency in the evaluation of malignant pulmonary artery stenosis compared with conventional DSA could be shown.

Between 1998 to 2000, the shoulders of 17 patients with rotator cuff tears were examined using magnetic resonance imaging preoperatively, and 6 and 12 months after open surgical repair. To assess the course of the supraspinatus muscle atrophy, the easily reproducible magnetic resonance imaging parameters occupation ratio and tangent sign in the Y-shaped view of the supraspinous fossa were evaluated and compared with the clinical examination. Occupation ratio is a quantitative parameter that reflects the area ratio, expressed as a percentage of the supraspinatus muscle belly to the supraspinous fossa. The tangent sign is a qualitative parameter that represents a line connecting the coracoid process and the apex of the scapular spine. Occupation ratio and tangent sign are reliable diagnostic tools in magnetic resonance imaging assessment of supraspinatus muscle atrophy. The sensitivity of the magnetic resonance imaging parameter occupation ratio is 75% and the specificity is 85%. The imaging parameter tangent sign has a sensitivity of 100% and a specificity of 85%. There is a significant relationship between occupation ratio, tangent sign, and improvement of strength and mobility registered in the score of Constant and Murley 12 months after surgery.

Purpose: To evaluate the comparative impact of magnetic resonance imaging (MRI) and bone marrow scintigraphy (BMS) in bone marrow metastases of solid tumors. Methods: In 20 patients with solid tumors MRI of the axial skeleton and whole-body BMS were retrospectively reviewed. Detectability of metastases, extent of disease and therapeutic implications were assessed. Results: In 15/20 (75%) patients MRI and BMS concordantly revealed bone marrow metastases of the axial skeleton. In nine of these 15 patients (60%) MRI showed more metastases. Local radiotherapy or surgery was performed in seven of these cases (78%). BMS detected additional metastases of the appendicular skeleton in 8/15 (53%) patients. In 4/20 cases (20%) the imaging findings were discordant. In three patients with degenerative changes ( n =2) or lipoma ( n =1) BMS was false positive. In another patient BMS failed to detect metastases proven by MRI and clinical follow-up resulting in subsequent radiation therapy. One patient had normal bone marrow. Conclusion: MRI appears to be more sensitive and specific in the detection of bone marrow metastases in the axial skeleton and is of clinical importance for subsequent local therapy.

The aim of this study was to define the imaging characteristics of primary and recurrent gastrointestinal stromal tumors (GIST) in computed tomography with respect to the tumor size. Computed tomography was performed in 35 patients with histologically confirmed gastrointestinal stromal tumors and analyzed retrospectively by two experienced and independent radiologist. The following morphologic tumor characteristics of primary ( n=20) and ( n=16) recurrent tumors were evaluated according to tumor size, shape, homogeneity, density compared with liver, contrast enhancement, presence of calcifications, ulcerations, fistula or distant metastases and the anatomical relationship to the intestinal wall, and the infiltration of adjacent visceral organs. Small GIST (5 cm) showed a sharp tumor margin with homogeneous density and structure on unenhanced and contrast-enhanced images, and were characterized by an intraluminal tumor growth. Intermediate sized GIST (5-10 cm) demonstrated an irregular shape, inhomogeneous density on unenhanced and contrast-enhanced images, a combined intra- and extraluminal tumor growth with aggressive findings, and infiltration of adjacent organs in 9 primary diagnosed and 2 recurrent tumors. Large GIST (10 cm), which were observed in 8 primary tumors and 11 recurrent tumors, showed an irregular margin with inhomogeneous density and aggressive findings, and were characterized by signs of malignancy such as distant and peritoneal metastases. Small recurrent tumors had a similar appearance as compared with large primary tumors. Computed tomography gives additional information with respect to the relationship of gastrointestinal stromal tumor to the gastrointestinal wall and surrounding organs, and it detects distant metastasis. Primary and recurrent GIST demonstrate characteristic CT imaging features which are related to tumor size. Aggressive findings and signs of malignancy are found in larger tumors and in recurrent disease. Computed tomography is useful in detection and characterization of primary and recurrent tumors with regard to tumor growth pattern, tumor size, and varied appearances of gastrointestinal stromal tumors, and indirectly gives hints regarding dignity and therefore prognostic outcome.

Introduction / objectives: Contrast-enhanced MRA (ce-MRA) has been claimed by many authors as a replacement of conventional angiography evaluating peripheral arterial occlusive disease. However, reliable detection of relevant stenoses (>70%) has to be provided for planning vascular interventions. Only few data in the literature focuses on this crucial problem. The purpose of this study was to evaluate this topic using a two-step body-coil-based MRA protocol. Methods and patients: Forty three patients presenting with 82 stenoses ≥50% and 61 stenoses >70% on conventional catheter angiogram received fast Gadolinium-DTPA-enhanced high resolution 3D MR angiography at 1.5 T covering the pelvic and peripheral vascular tree in two examination steps using the body-coil. The data were evaluated double-blinded by three readers distinguishing moderate (50–70%) from severe stenoses (>70%). Results: Overall sensitivity/specificity/accuracy was 84/60/70% evaluating 143 segments. Specificity was rather poor in the iliac (58%) and crural (50%) region and moderate in the femoral and popliteal level (73%). The negative predictive value ranged between 78 and 91%. The grade of stenosis tend to be overestimated rather than underestimated in all levels with positive predictive values between 55 and 78%. Discussions and conclusions: Body-coil-based contrast-enhanced MRA has limited potential in distinguishing moderate from severe stenoses in peripheral occlusive disease. Overestimations are more common than underestimations. Both occur mainly in small-sized crural arteries but also in larger iliac arteries where vessel course in partition direction may cause inadequacy between voxel size and lumen diameter in severe stenosis.

Our objective was to optimize bolus administration and sequence setting in gadolinium-enhanced magnetic resonance (MR) angiography of the hands. Elliptically reordered three-dimensional (3D) spoiled gradient-echo sequence with non-slab-selective radio frequency excitation was optimized according to the measurements of arterial and venous time-signal curves in 21 patients. Great variations in bolus arrival time and arterio-venous transit time could be observed. In most patients high-quality arterial depiction could be obtained with minor venous contamination. Contrast-to-noise, spatial resolution, and selective arterial filling is still a challenge for 3D MR angiography of the hand but can be optimized using Gadolinium-BOPTA and a dedicated pulse sequence setting with exact bolus timing.

Most recently, time-resolved 2D MRA after injection of a contrast agent bolus for various applications has been proposed. Similar to conventional digital subtraction angiography (DSA), 2D MR DSA offers the ability to observe the dilution of the bolus in the vascular system during the passage with a temporal resolution considerably below 1 sec. The purpose of this paper is to present strategies to improve the inherent low signal-to-noise ratio of 2D angiograms while retaining some temporal resolution. This can be achieved by applying algorithms for time series analysis as used in functional MRI. The significantly improved image quality is demonstrated on examples from clinical studies from bronchial MRA as well as cardiovascular MRA. In addition to the increased signal-to-noise ratio, correlation analysis leads to suppression of background signals and to a better discrimination of overlapping vessels. Further improvements in the temporal discrimination of vessels is afforded by the use of consecutive multiple contrast agent boli as demonstrated by numerical simulations and experiments. Magn Reson Med 43:303–309, 2000. © 2000 Wiley-Liss, Inc. In the last three years, the development of gradient systems for ultra fast imaging has made time-resolved projection angiography after administration of a bolus of contrast agent (c.a.) feasible (1, 2). Similar to conventional x-ray DSA, a thick slab or a non-slice selective projection through the volume is imaged consecutively with a temporal resolution below 1 sec, using an ultra-rapid T1-weighted gradient echo sequence. This offers the possibility to directly observe the dynamics of c.a. propagation. Due to the short image acquisition times, projection angiography is very insensitive to any kind of motion. This allows vascular imaging of the thorax without breathhold and even without synchronization of data acquisition to the ECG-signal. Moreover, the method avoids the requirements for exact bolus timing as in 3D MRA in which venous overlap obscure the delineation of the arteries when sampling of central k-space lines does not hit the peak concentration of the contrast agent in the arteries (3). Background signal that mainly arises from fatty tissue due to short T1 can be eliminated by (complex) subtraction of an image acquired before the c.a.-injection. Additional depth information can be obtained by acquiring images alternatively under different projection angles. Several clinical application of 2D MR DSA have already been reported, demonstrating the diagnostic feasibility of the method especially for vessel segments of the vascular system with short arterial transit and strong venous return like the carotid arteries, intracranial vessels or the pulmonary vessels (4–8). The major drawback of acquiring the 2D samples with a high temporal resolution is the low signal-to-noise ratio (SNR) of the projection images. The SNR can, of course, be improved by averaging over n consecutive projection images, which, however, will lead to a loss of functional information in the time resolved scan. The purpose of this paper is to propose and discuss the use of correlation analysis (9) as a post-processing strategy to improve the SNR in projection angiographic images while maintaining the functional information about the propagation of the c.a. bolus.

To evaluate whether the selenium detector (Thoravision) provides sufficient diagnostic confidence in digital pelvic imaging compared with a conventional screen-film combination.In 75 patients, pelvic imaging with conventional screen-film and isodose selenium radiography using a dedicated postprocessing mode was compared independently by three radiologists. The depiction of cortical and cancellous bone was evaluated in the iliac wings, sacral and pubic bones, acetabulum, femoral head, and trochanter. Demarcation of soft tissue was assessed in the iliac and trochanteric region.Visualization of cortical bone and soft tissue in the iliac area as well as soft tissue and cortical and cancellous bone in the trochanteric region was significantly superior with the selenium detector. However, conventional imaging was better in the trabecular bone of the sacral region, where results with the selenium system were particularly poor.The selenium detector (Thoravision) is advantageous in imaging soft tissue adjacent to the iliac wings and the trochanter, but results for the cancellous sacral bone are poor. Further modifications of postprocessing modes may lead to improved depiction of this critical pelvic area.

RATIONALE AND OBJECTIVES. A large variety of cardiac MRI sequences have been introduced for heart morphology evaluation. The aim of this study was to establish a practicable and robust examination protocol for standard high-field systems applying nongradient echo sequences with single- and multislice acquisition. METHODS. Fifty-one patients received electrocardiogram-gated MRI of the heart with “black-blood” preparation, comparing three single-slice and three multislice sequences with a T1-weighted turbo spin echo reference sequence. Demarcation of the left ventricular myocardium and cavity and the extent of flow and motion artifacts were assessed. RESULTS. The myocardium and left ventricular cavity were depicted best with the single-slice T1- and T2-weighted turbo spin echo sequence. The nonbreath-hold multislice sequences produced marked artifacts and therefore were of poor diagnostic value. The TIRM haste sequence was best suited for fat suppression. The T2-weighted breath-hold single-shot sequence with half-Fourier imaging proved to be most appropriate for multislice imaging. CONCLUSIONS. Sufficient depiction of heart morphology with comprehensive evaluation of signal changes can be achieved using nongradient spin echo and turbo spin echo sequences with breath-holding. For rational imaging of myocardial and heart chamber morphology, multislice and single-slice sequences should be combined.

To evaluate the diagnostic utility of indirect MR arthrography of the unexercised glenohumeral joint in patients with rotator cuff tears confirmed by arthroscopy or arthrotomy as the gold standard.Twenty-six patients underwent conventional MR imaging and indirect MR arthrography of the stationary glenohumeral joint using a wrap-around surface coil. Unenhanced T1-weighted spin echo/T2-weighted fast spin echo sequences and T1-weighted gradient echo sequences, adding spectral fat suppression after intravenous administration of contrast medium, were performed in the oblique coronal and oblique sagittal planes. Images were analyzed by three experienced radiologists in consensus. Levels of diagnostic confidence were evaluated using a four-point scale of diagnostic certainty.Performing indirect MR arthrography of the unexercised shoulder leads to a diagnostically efficient enhancement of joint fluid (120% at 4 minutes and 145% at 8 minutes after intravenous injection of gadodiamide). In terms of soft tissue delineation, characterization of rotator cuff tears was significantly improved by using enhanced fat-suppressed T1-weighted gradient echo sequences compared with conventional MR imaging.Indirect MR arthrography without glenohumeral joint exercise in the diagnosis of rotator cuff tears is feasible and represents a more convenient and less time-consuming alternative to indirect MR arthrography after joint exercise.

An unusual case of lipid embolization to brain and kidney after lymphography in a patient with non-Hodgkin lymphoma of the upper anterior mediastinum is reported. Contrast material-enhanced echocardiography demonstrated a right-to-left shunt to the left atrium without evidence of a patent foramen ovale. Echo contrast particles were transiently present within the tumor surrounding the great vessels.

Smooth muscle tumors (SMT) arising in the abdominal cavity and retroperitoneum are very rare. Extending from the muscular layer SMT can affect any part of the gastrointestinal tract but will be found in the stomach and small intestine preferentially. The liver and bile ducts are exceptional sites of origin. SMT deriving from abdominal veins, in particular the inferior vena cava, have been reported in several cases. We present an uncommon case of a recurrent leiomyoma arising in the gastroduodenal ligament. Due to close contact either the common bile duct or the portal vein seemed to be most suggestive for tumors origin.

Our objective was to describe the imaging features of hypothenar hammer syndrome using minimally invasive contrast-enhanced MR angiography in comparison with oscillography study. In five patients with hypothenar hammer syndrome Gd-BOPTA-enhanced elliptically reordered 3D pulse sequence MR was compared with oscillography findings and clinical symptoms focusing on angiographic appearance of vessel injury, distribution pattern of hand vasculature and joining branches between the radial and ulnar artery supply. All patients showed segmental occlusion at the site of trauma impact with varying involvement of the superficial palmar arch, common volar digital arteries. Embolic disease was present in 50% of patients and could be clearly identified with MRA. Good correspondence was found between angiographic appearance including the presence of collaterals, clinical symptoms and oscillography. Bilateral comparison was helpful in distinguishing between vessel variants and pathology. Bilateral Gd-BOPTA-enhanced MR angiography is a minimally invasive method to depict clearly the localization and extent of vessel injury in hypothenar hammer syndrome providing valuable information about distribution pattern of hand vasculature and presence of collaterals; however, no flow data can be obtained.