Direct MR arthrography of the shoulder: 2D vs. 3D gradient-echo imaging.

The aim of this study was to determine the value of a fat suppressed 3D gradient-echo sequence (GRE) data set in comparison to a 2D GRE sequence in direct MR arthrography of the shoulder. For this purpose we examined 50 consecutive patients with subacute or chronic disorders of the shoulder using a 1.5 T scanner: Transverse T1-weighted 2D (slice thickness 4 mm) and 3D GRE (slice thickness 1.5 mm reconstructed from 3 mm), oblique coronal T2- and T1-weighted turbo spin-echo (TSE) and sagittal T1-weighted TSE with fat saturation were applied. Visual image analysis of anatomical and pathological structures was performed by two independent observers. A correlation to surgical results was available in 21 patients. Transverse GRE sequences were well suited for analysis of the anterior/posterior labrum, the middle glenohumeral ligament, and cartilage. 3D GRE with fat suppression was slightly superior to 2D GRE without fat suppression in the evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament, whereas for cartilage no significant differences were found between both sequences. Concerning pathological findings, in most of the cases 2D delivered the same results as 3D. In conclusion, a T1-weighted 3D GRE data set with fat saturation in transverse orientation may be useful for evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament. However, similar measured slice thickness of 3 mm-even if interpolated to 1.5 mm-compared to a 2D sequence with 4 mm does not provide significant diagnostic advantages.

Fluoroscopically triggered contrast-enhanced 3D MR DSA and 3D time-of-flight turbo MRA of the carotid arteries: first clinical experiences in correlation with ultrasound, x-ray angiography, and endarterectomy findings.

The aim of this article was to obtain initial experiences with fluoroscopically triggered contrast-enhanced (CE) 3D MR DSA with elliptical centric k-space order and 3D time-of-flight (TOF) turbo MRA of the carotid arteries. In this prospective study we examined 16 consecutive patients with suspicion of atherosclerotic disease involving the carotid arteries. Ultrasound was available in all, x-ray angiography in 12, surgical correlation in 9, and intraoperative x-ray angiography in 4 patients. All examinations were done on a 1.5 T unit applying: transverse plain 3D TOF turbo MRA and coronal CE MRA with fluoroscopic triggering. Combining head and neck array coils allowed the visualization of supraaortic arteries from the aortic arch to the circle of Willis. MRA results (maximum intensity projections) were compared with x-ray angiography, ultrasound, and inspection of endarterectomy specimens. Volume rendering was performed in selected cases additionally. Agreement between CE MRA, 3D TOF turbo MRA and x-ray angiography regarding stenoses of the internal and external carotid artery was very good. CE MRA was able to detect correctly intracranial stenoses, but delineation of the aortic arch and proximal common carotid arteries was sometimes reduced. Volume rendering was suited for visualization of MRA images providing a realistic three-dimensional impression. In conclusion, high-resolution fluoroscopically triggered CE MRA as non-invasive technique is another important step on the way to replace invasive x-ray angiography for the evaluation of atherosclerotic carotid artery disease. High resolution 3D TOF turbo MRA might be a helpful adjunct to increase the diagnostic reliability for the carotid bifurcation.

Palliation of a primary malignant melanoma of the distal esophagus by stent implantation. Report of a case.

BACKGROUND: A 55-year-old woman suffering from progressive dysphagia, retrosternal pain, and annoying foetor ex ore is described. Esophagogastroscopy showed a dark, necrotic tumor extending from 28 cm below the front teeth to the esophagogastric border, and biopsy showed it to be a primary malignant melanoma. The underlying progressive tumor stage with pericardial infiltration and intra-abdominal lymph node metastasis precluded the possibility of curative surgical treatment. METHODS: For palliation, we implanted a metal stent (Ultraflex, Microvasive, Boston Scientific Corporation, Watertown, MA, USA) in the distal esophagus to alleviate the dysphagia. RESULTS: Permanent recanalization of the tumor-obstructed esophagus by stent implantation alleviates symptoms, thereby significantly improving quality of life. Radiochemotherapy can be performed despite the presence of the stent. CONCLUSIONS: Surgery is the therapy of choice for resectable primary malignant melanoma of the esophagus. Endoscopic therapy should be considered for alleviating dysphagia if surgery is impossible.

[A hybrid technique for the automatic floating table MRA of peripheral arteries using a dedicated phased-array coil combination]. / Eine Hybridtechnik für die Schrittverschiebungs-MRA der Becken-Bein-Arterien mit einer dedizierten phased-array-Spulen-Kombination.

PURPOSE: We introduce a hybrid technique which allows a high resolution MRA of the peripheral arteries with a dedicated phased-array coil using the floating table technique. MATERIALS AND METHODS: Five patients with peripheral arterial occlusive disease were examined within one week with i.a. DSA and MRA using the hybrid technique. MRA examinations were done on a 1.5 T system. At first, pelvic arteries were examined in a single step mode applying the CareBolus technique. Subsequently, thighs and lower legs were examined using the floating table mode. 125 vascular segments were evaluated. RESULTS: The hybrid technique proved to be robust and could be performed in each case. Mean examination time was about 30 min. For 117 vascular segments no difference was found between i.a. DSA and MRA. Three segments revealed a higher grade of stenosis in DSA than in MRA, five segments were graded higher in MRA than in DSA. Occlusions were visualized identically in both methods. Venous overlap had no relevant effects on image evaluation. CONCLUSIONS: This hybrid technique in combination with phased-array coils allows a high resolution MRA of the peripheral arteries with very good image quality. If future studies confirm reduced venous overlap, this method may be an alternative also for users of the floating table MRA with the body resonator.

[CT-guided percutaneous core biopsy: Effective accuracy, diagnostic utility and effective costs]. / CT-gesteuerte perkutane Schneidbiopsie: effektive Genauigkeit, diagnostischer Nutzen und effektive Kosten.

PURPOSE: The value of a diagnostic technique does not only depend on its sensitivity, specificity and accuracy, but also on how its results affect clinical management. This effect is represented by the values effective accuracy and the diagnostic utility which were determined for CT-guided coaxial core biopsies in this study. MATERIALS AND METHODS: 180 consecutive biopsies were analyzed. The results were analyzed with the help of a logistic regression analysis with regard to the organ regions biopsied, the size of the needle used, and the number of tissue cores taken. Correct results that were not accepted as diagnostic clinically and resulted in additional biopsies were scored together with the false results under negative utility coefficients. RESULTS: The sensitivity, specificity and accuracy of all the tests amounted to 91.1 %, 100 %, and 93.3 %, respectively. The diagnostic utility of the biopsies varied between 66 % for the liver and pancreatic lesions, and 88 % for the non-organ related retroperitoneum. In those cases where more than three tissue cores were taken the results were statistically significantly better in terms of effective accuracy and diagnostic utility. No significant differences were found with regard to different needle sizes in the biopsied organ regions. The lowest clinical acceptance was observed for the histological findings "scar tissue" and "inflammation". CONCLUSION: CT-guided coaxial biopsies offer a high degree of sensitivity, specificity and accuracy, as well as a low rate of therapeutically relevant complications. With increasing use of differentiated strategies in therapy for malignomas percutaneous biopsies play a very important role in the management of these diseases. Prospective studies should further evaluate the effective accuracy and diagnostic utility of core biopsies also in comparison to fine needle aspiration biopsies (FNAP).

[Pseudoaneurysm of the hepatic artery--a rare complication after orthotopic liver transplantation]. / Pseudoaneurysma der A. hepatica--eine seltene Komplikation nach orthotoper Lebertransplantation.

INTRODUCTION: Pseudoaneurysm of the hepatic artery is a rare complication of liver transplantation, the most common cause of which--apart from technical surgical problems--is an infection. The most common symptoms are rupture and hemorrhage. METHOD: The present case report describes an asymptomatic pseudoaneurysm of the hepatic artery following liver transplantation, and its treatment. RESULTS: In this patient, an pseudoaneurysm involving an eroded branch of the hepatic artery was found. Surgical treatment consisted in the excision of the aneurysm and oversewing of the branch of the hepatic artery. CONCLUSION: The potential for rupture and hemorrhage makes surgical intervention mandatory even in asympotomatic patients with pseudoaneurysm of the hepatic artery. The surgical procedure depends on the local situation and the time elapsed since transplantation. Preservation or reconstruction of the arterial perfusion is essential.

A low-field MR system in acute traumatological imaging in radiology. Technical note.

PURPOSE: In this paper initial clinical observations with the application of a new low-field MR system in acute musculoskeletal imaging in radiology are presented. MATERIALS AND METHODS: This system is designed as a three-sided open permanent magnet with a revolving table. Main magnetic field strength is 0.2 T, maximal gradient field strength 20 mT/m, and minimal gradient rise time is 800 microseconds. First clinical experiences in 25 patients with acute trauma of peripheral joints were obtained. The following sequences were applied: gradient-echo (GRE) STIR, T1-weighted spin-echo, and PD- and T2-weighted turbo spin-echo. Correlation with the findings of high-field MR (1.5 T), plain radiograms (including stress views), CT or ultrasound was available in each patient confirming the low-field diagnoses. Furthermore, phantom measurements were performed to verify the spatial resolution of the system for some sequences with typical measurement parameters. DISCUSSION: This low-field system has several advantages: fast and economic installation, limited required space, easy operation, and high patient comfort. The medical benefit of such a system integrated in the traumatological suite of a radiological department seems to be evident due to the impact on the early initiation of the correct therapy which avoids additional diagnostic procedures and therefore may reduce costs. Implementation of such a system may be useful, if installation of an additional high-field scanner is not possible due to economic considerations.

[Fully automated floating table MR angiography of pelvic and leg arteries: initial clinical results]. / Vollautomatische Schrittverschiebungs-MR-Angiographie der Becken-Bein-Arterien: Erste klinische Ergebnisse.

The aim of this study was to obtain first clinical experiences with magnetic resonance angiography (MRA) with digital subtraction (MR-DSA) using an automatic floating table for visualization peripheral arteriosclerotic occlusive disease (paod). We examined 10 patients on a 1.5 T MR unit applying a fast MRA technique (3D FLASH) with intravenous application of positive contrast agent. MR-DSA examinations were compared with the gold standard intraarterial (i.a.) DSA. MR-DSA proved to be useful for routine application which could be performed sufficiently in all patients. MR-DSA and i.a. DSA showed comparable results for imaging of the pelvic and upper leg arteries. Looking at the thighs image quality of MR-DSA did not match the image quality of i.a. DSA in every case. This was due to venous overlap and in comparison to i.a. DSA reduced signal-to-noise ratios. However, clinical findings, obtained with MR-DSA, were sufficient for adequate therapy planning. Our preliminary results reveal the potential of this new technique to become a realistic, robust, and non-invasive alternative to i.a. DSA in the diagnosis of paod.