[Characterization and staging of renal tumors: significance of MRI diagnostics]. / Charakterisierung und Staging von Nierentumoren: Bedeutung der MRT-Diagnostik.

PURPOSE: Retrospective evaluation of MRI in the diagnosis of renal masses and determination of the correlation of MRI with histology or follow-up. MATERIALS AND METHODS: 46 consecutive patients (13 female, 33 male, mean age 64.7 yrs) with suspected renal tumors were examined with a 1.5 T MR scanner using a standardized protocol (TSE T2fs, 2DGRE T1, dynam. ce3DGRE T1fs, ce2DGRE T1fs, ce3DGRE urogram). RESULTS: 142 renal lesions were found with diameters of < 2 cm up to 14 x 18 cm. A primary classification as solid and cystic lesions was performed according to MRI criteria. In 29 cases we found lesions bilaterally, in 17 patients only in one kidney, and in four cases we found multifocal renal tumors unilaterally (n = 3) or bilaterally (n = 1). In 22 patients with renal tumors, cystic lesions could be seen as well. In 19 cases these were uncomplicated cysts, and in 3 cases these were complicated cysts. 35/43 lesions were histologically proven solid vascularized tumors (29 renal cell carcinomas, 6 urothelial carcinomas), five additional masses with tumor signs in MRI appeared to be progressive during follow-up thus suggesting malignancy, and one case was a multifocal bilateral renal tumor. 3/43 lesions were initially reported as being suspected of malignancy but were proven during follow-up or histologically to be benign. Tumor thrombus was depicted in MRI in the renal vein in 5 cases, stretching into the IVC in 4 cases and proven histologically in 4 and 3 cases, respectively. Of these solid masses, 99 cystic lesions could be differentiated clearly in MRI (88 simple cysts, 11 complicated cysts) that remained unchanged during follow-up (6 - 65 months) or were proven to be cysts histologically. In 17 cases these cysts were bilateral, in 19 cases unilateral, and 33 kidneys showed multicystic changes. In characterizing renal masses, MRI showed a positive predictive value of 93 % for the diagnosis of a malignant tumor. The T-stage of histologically proven renal cell carcinomas using MRI was correct in 89 %. CONCLUSIONS: MRI is a valid modality for characterizing and staging renal masses using a suitable sequence protocol that includes dynamic ce studies. Venous tumor invasion can be depicted safely. MRI can be employed alternatively to state-of-the-art ceCT and additionally to CT in unclear cases.

[Contrast-enhanced MR angiography (CEMRA) in peripheral arterial occlusive disease (PAOD): conventional moving table technique versus hybrid technique]. / Kontrastverstärkte MR-Angiographie (CEMRA) bei peripherer AVK (pAVK): konventionelle Tischverschiebetechnik versus Hybrid-Technik.

PURPOSE: In peripheral arterial occlusive disease (PAOD), angiographic evaluation of the entire aortopedal arterial system is mandatory. In a randomized study, two different protocols of CEMRA were evaluated prospectively to compare their diagnostic quality and clinical usefulness. PATIENTS AND METHODS: 80 patients (males n = 60, females n = 20, median age = 70 years, diabetics n = 27) with PAOD were examined with a 1.5 T system (40 mT/m) using a dedicated phased array peripheral vascular coil. Protocol A consisted of a single injection of Gd-BOPTA with consecutive craniocaudal image acquisition and protocol B of two injections, with the first injection of Gd-BOPTA followed by image acquisition of the popliteocrural and pedal segments and the second injection followed by acquiring the aortoiliac and femoral segments (hybrid technique). The evaluation of the arterial system was directed to the iliac, femoral, popliteocrural and pedal arteries. RESULTS: The visualization of the entire aortopedal vascular system was of diagnostically good or satisfactory quality in 16 of 40 patients using protocol A and in 29 of 40 patients using protocol B (iliac 40 vs. 37, femoral 40 vs. 40, popliteocrural 35 vs. 37, pedal 16 vs. 29); without the pedal station the number increased to 35 of 40 patients for both protocols. The reason of diagnostic limitations was an arteriovenous overlap in 24 of 80 cases, with 19 of 40 cases for protocol A and 5 of 40 for protocol B, located exclusively in the cruropedal region. CONCLUSION: Moving table hybrid CEMRA is superior to conventional technique in craniocaudal direction by producing less venous overlap of arteries and is especially more suitable for the diagnostic evaluation of the cruropedal region.

Abdominal aortic aneurysm in Behçet's disease: treatment with endovascular stent graft.

A case of acute rupture of an abdominal aortic aneurysm in a patient with Behçet's disease is reported. The patient was successfully treated by implantation of an endovascular stent graft. The preinterventional diagnostic procedures and the postinterventional follow-up are described and the benefit and risk vs open surgery is discussed.

[Performance of different CT angiography imaging modalities in detecting renal artery stenoses]. / Leistungsfähigkeit verschiedener Darstellungsmodalitäten der CT-Angiographie beim Nachweis von Nierenarterienstenosen.

PURPOSE: Purpose of the study was to compare the sensitivity and specificity of various display modalities in the detection of renal artery stenosis. In particular, the difference between hard-copy reading and interactive analysis at the workstation was assessed. MATERIALS AND METHODS: Selected patients (n = 31) with expected suboptimal conditions for CT angiography due to long-standing hypertension and compromised renal function were included. Six radiologists evaluated independently a total of 77 renal arteries with 49 renal artery stenoses proven by angiography. Image analysis included: mode A: interactive display, analysis of multiplanar reformats and axial sections at the workstation, mode B: visualization of MIPs in the coronal and axial planes as hard copies only, mode C: visualization of MIPs and axial sections as hard copies only. RESULTS: The following sensitivities and specificities were found for internal readers and (readers from outside institutions): mode A: 94.8%, 87.9%, mode B: 97.7% (95.1%), 80.3% (75.4%); mode C: 97.0% (95.3%), 78.8% (76.6%). The differences were statistically not significant (p > 0.05). CONCLUSIONS: Standardized hard copies of MIPs plus axial CT provide sufficient accuracy to detect renal artery stenosis compared to interactive imaging even in this highly selected group of patients.

[MR angiography: abdominal veins]. / MR-Angiographie: Venen des Abdomens.

UNLABELLED: Conventional MR-angiography (MRA) of the abdominal veins is a noninvasive and useful technique that has been accepted in clinical routine. The aim of this presentation is to evaluate the actual status of MRA including contrast-enhanced techniques and to compare clinical results with alternative diagnostic procedures such as ultrasonography, CT, and digital subtraction angiography (DSA). MATERIAL AND METHODS: Four different MRA techniques available today are presented that can be used for examination of the abdominal veins including sequence-parameters of the 2D TOF-FLASH technique, the 2D/ 3D PC techniques, the 2D True FISP technique, and the ultrafast 3D FLASH technique following i.v. administration of Gd-DTPA. RESULTS: From data of the current literature usefulness and accuracy of MRA is demonstrated in different provinces of the abdominal veins. DISCUSSION: On the basis of specific questions that are focused on MRA of the abdominal veins the value of this method is discussed under consideration of different techniques. MRA is evaluated under consideration of critical vascular areas, the role of contrast-enhanced MRA, suitable doses of contrast material, and new hard-ware configurations in the future. Furthermore, advantages and drawbacks of conventional MRA are compared with contrast-enhanced MRA-techniques, ultrasonography, CT and DSA.

[Magnetic resonance tomography and magnetic resonance angiography in diagnosis of complicated popliteal artery aneurysm]. / MRT und MRA in der Diagnostik des komplizierten Popliteaaneurysmas.

Regarding the frequency of aneurysms, the popliteal artery comes third behind the abdominal aorta and the iliac arteries. In up to 50% of cases a sudden limb-threatening thrombotic occlusion may occur. Early surgical intervention is the therapy of choice. We report the case of a 56-year-old patient whose popliteal aneurysms (PAs) in both legs had been bypassed with a venous graft some years previously. He presented with acute pain and tumescence in the left popliteal fossa combined with inflammatory symptoms. Neither ultrasonography nor DSA could distinguish between an extravascular inflammatory process, an anastomotic aneurysm and a partial reperfusion of the original PA due to a leaking anastomosis. The correct diagnosis was provided by MRI in combination with MRA, confirmed by the intraoperative findings. The value of MRA in the diagnostic imaging of the vasculature of the lower extremities is discussed and compared alternative methods.

[MR angiography using Gd-DTPA in staging of abdominal aortic aneurysm: a correlation with DSA and CT]. / MR-Angiographie mit Gd-DTPA zum Staging des abdominellen Aortenaneurysmas: Korrelation mit DSA und CT.

PURPOSE: To evaluate a contrast-enhanced (CE) MRA sequence for staging AAA. METHODS: In 24 patients (male = 20, female = 4, age = 44-81 y) with known AAA the abdominal aorta and its branches including the iliac arteries were imaged, using a 3D GRE-FISP sequence (1.5 T, TR/TE/FA = 25/6/35, slab = 100-140 mm, 32 part., FOV = 440-450 mm, matrix = 256 x 256) during an i.v. infusion of 40 ml of gadopentate dimeglumine. In addition, representative axial single slices (2D breath hold FLASH-sequence. TR/TE/FA = 82/5/30) were acquired following contrast application. MR-results were correlated with i.a. DSA and CT studies. RESULTS: With CE-MRA, AAA (n = 24) and iliac aneurysms (n = 17) could be evaluated in all cases (sens. = 100%, spec. = 100%) including luminal patency and mural thrombus. 50/54 renal arteries could be identified, 4/6 accessory renal arteries (sens. = 66.6%, spec. = 100%), 8/9 renal artery stenoses > 50% (sens. = 88.8%, spec. = 89.3%), 1/1 renal artery occlusion and 7/8 iliac artery stenoses > 50% (sens. = 87.5%, spec. = 97.5%) were depicted correctly. Proximal portion of sup. mes. art. could be detected and evaluated in 21/24 cases. Quantitative determination of therapeutically relevant vascular parameters using MRA was comparable to DSA and CT. CONCLUSION: CE-MRA is a useful method for staging of AAA and may become the method of choice when ultrafast MR techniques are used.

[Percutaneously implanted permanent vena cava filter: follow-up of 117 consecutive patients]. / Perkutan implantierte permanente Vena-cava-Filter: Verlaufsbeobachtungen bei 117 konsekutiven Patienten.

PURPOSE: Retrospective review of indication, insertion technique and problems, complications and effectiveness of 5 different filter designs implanted during a period of 5 years. MATERIALS, PATIENTS AND METHODS: We inserted one Filcard-filter, 4 Antheor DC 3 perm.-filters, 17 Trigon/Cardial-filters, 28 Titan-Greenfield-filters (modified hook) and 65 LGM 30 D/U Vena Tech-filters via a femoral (n = 111) or a jugular (n = 4) approach in 115 of 117 patients. Indication was acute deep thrombosis of the iliac or femoral vein with and without pulmonary embolism (PE) in patients with contraindication to, or unsuccessful, anticoagulation therapy or lysis. Follow-up was possible in 92 patients. RESULTS: In two of 117 patients the filter could not be implanted due to dissection of the left iliac vein. In the other 115 patients we achieved an orthograde position of the filter in 78%, 22% of the filters tilted more than 15 zero and 25% had been opened incompletely. We noticed late filter dislocation in 4 cases, deep vein thrombosis of the access vein in two cases, one haematoma of the insertion site, three asymptomatic perforations of filter struts through the caval wall, 14 filter induced thromboses of the vena cava (15.2%) and 13 recurrent PE (14.1%), fatal in 5 cases (5.4%). CONCLUSION: The implantation of vena caval filters as a prophylaxis of PE is easy and of low risk. Because of the relatively high rate of recurrent PE (14.1%) in our series after implantation, the effectiveness must be judged critically.

[Vena cava invasion in adrenal gland tumors: findings in nuclear magnetic resonance tomography]. / Kavazapfen bei Nebennierentumoren: Kernspintomographische Befunde.

In rare cases, large adrenal masses with a suspicion of malignancy exhibit tumor extension into the adrenal vein and inferior vena cava. When planning surgery, the relationship of the extension to the inferior vena cava is of decisive importance. We describe in two cases on the detection of a tumor thrombus in the inferior vena cava arising from a malignant adrenal mass by means of MR angiography (TOF, coronary 2D GRE images [FLASH], 3 slices acquired during 15 second apnea). The angiograms correlated well with the results of DSA venacavography and with the intraoperative findings. Thus, MRA has been demonstrated to be suitable for the certain proof of a venous tumor thrombus not only in cases of renal cell carcinomas but also in cases of malignant adrenal masses. The method should be applied whenever there is evidence of a venous involvement in the adrenal MR images.

[Magnetic resonance tomography of the scrotum. Experiences with 129 patients]. / Magnetresonanztomographie des Skrotums. Erfahrungen an 129 Patienten.

In our study 129 patients underwent MR imaging for evaluation of the scrotum with spin-echo pulse sequence (proton density and T2-weighted images). The final diagnosis was confirmed by surgery in 54 patients. Our findings show that MRI is a powerful supplementary technique for scrotal imaging when ultrasound findings are unclear or are inconsistent with the clinical history. MRI can reduce the number of unnecessary exploratory operations on the testis, though surgery is unavoidable if the findings are equivocal. Differentiation and specification of tumours cannot be achieved by MRI, nor does it allow accurate evaluation of subacute torsion of the testis. In these cases dynamic MRT following intravenous administration of Gd-DTPA may improve the diagnostic accuracy.

[Rational diagnosis of traumatic aortic rupture]. / Rationelle Diagnostik der traumatischen Aortenruptur.

The traumatic aortic rupture has an extremely high spontaneous mortality rate. Important for surviving the trauma is a fast and efficient diagnostic procedure. The suspected diagnosis results from relatively typical criteria in the chest radiograph, especially the continuous widening of the mediastinum. The diagnostic procedure of 26 patients with polytrauma, abnormal chest radiograph and further examinations (intra-arterial digital subtraction angiography [i.a.DSA]: n = 10, contrast-enhanced CT: n = 19, CT and DSA: n = 5) was reviewed. Six patients had an aortic rupture. In 4 patients the diagnosis was confirmed by angiography, in 2 patients by surgery. The specificity was 100% for DSA and 40% for CT. To ensure the suspected diagnosis of a traumatic aortic rupture we therefore primarily recommend angiography. Whenever CT is performed in case of head injury, a CT of the thorax can be added in order to exclude mediastinal bleeding and to reduce the need for angiography.