Publications (52)137.28 Total impact
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Chapter: Tumoren der Niere und der ableitenden Harnwege
04/2007: pages 179-201; -
Article: [Radiologic features of inflammatory pseudotumors].
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ABSTRACT: Inflammatory pseudotumor is a rare benign tumor entity. Because inflammatory pseudotumors mimic malignant tumors both clinically and radiologically, the radiologist should be familiar with this entity. Inflammatory pseudotumor most commonly involves the lung and the orbit, but it has been reported to occur in nearly every site in the body. For making a definite diagnosis a biopsy is often essential. The treatment options are varied and consist of surgery, high-dose steroids, irradiation, and chemotherapeutics.RöFo - Fortschritte auf dem Gebiet der R 12/2005; 177(11):1506-12. · 2.76 Impact Factor -
Article: [Diagnostic imaging of vascular leiomyosarcomas].
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ABSTRACT: Primary vascular leiomyosarcomas are very rare tumors, with the venous variety most often arising from the inferior caval vein and the arterial variety from the pulmonary artery. The tumors show either an exclusive intra- or extravascular pattern or a mixed growth pattern. The clinical symptoms depend on tumor location, with intraluminal tumors of the inferior caval vein causing edema or a Budd-Chiari syndrome. Leiomyosarcomas of the pulmonary artery can mimic chronic central or recurrent peripheral pulmonary embolism. Contrast enhanced spiral CT with multiplanar reconstruction is the diagnostic method of choice when a vascular leiomyosarcoma is suspected. MRI with MR-angiography can be added. If a tumor of undetermined origin shows a broad contact with a vessel and/or an intraluminal component, possible primary vascular leiomyosarcoma should be included in the differential diagnosis.RöFo - Fortschritte auf dem Gebiet der R 03/2004; 176(2):183-90. · 2.76 Impact Factor -
Article: [Adrenal gland metastasis of clear-cell renal cell carcinoma: a diagnostic problem in chemical-shift MRT imaging].
RöFo - Fortschritte auf dem Gebiet der R 10/2003; 175(9):1275-7. · 2.76 Impact Factor -
Article: [Cystic renal lesions].
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ABSTRACT: Cystic renal lesions are most often simple or complicated cysts, which can be seen solitary or as part of cystic renal disease. The minority of these lesions are benign or malignant cystic tumors. The classification of cystic renal masses by Bosniak (category l - IV) based on specific ultrasound and CT features is very useful for the characterization of the lesion and for the therapeutic decision. The main objective of this classification is to differentiate nonsurgical (category II) from surgical cystic masses (category III/IV). Ultrasound is the first modality of choice in the diagnostic work-up of cystic renal masses, because an accurate and economically reasonable diagnosis of the frequent simple cyst can be made by maintaining rigid ultrasound criteria of the Bosniak classification. If a complicated cyst or a cystic tumor is suspected a three phasic contrast-enhanced CT of the kidneys should be performed. MRI is superior to CT in the characterization of complex cystic masses.RöFo - Fortschritte auf dem Gebiet der R 08/2003; 175(7):892-903. · 2.76 Impact Factor -
Article: [MRI in cavernous transformation of the portal vein: secondary biliary abnormalities and portoportal collaterals].
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ABSTRACT: Evaluation of portoportal collateral vessels and associated biliary abnormalities in patients with cavernous transformation of the portal vein by MRI. Review of 34 MRI examinations performed on patients with angiographically or MR-angiographically proven cavernous transformation. The analysis included the pattern of the portoportal collateral circulation and the abnormalities of the biliary system, such as wall thickening, stenosis, dilations and irregularities of the extra-and intrahepatic bile ducts. 23 (67.6%) of 34 patients with cavernous transformation had paracholedochal portoportal collateral vessels, with 22 (64.7%) showing visible luminal channels. Epicholedochal venous collaterals could be observed in 8 (23.5%) patients. 24 (70.5%) of 34 patients demonstrated biliary abnormalities due to portoportal collaterals, leading to stenosis with dilatation of the proximal bile ducts in 8 (23.5%) patients. The ductal walls were irregular in 7 (20.5%) patients, and thickened in 11 (32.3%). The gallbladder wall was thickened in 4 (12.9%) patients. Portoportal collaterals in patients with cavernous transformation of the portal vein can be identified by MRI. These collaterals frequently alter the biliary system, which must be considered in differential diagnosis of biliary abnormalities observed in the presence of portoportal collaterals.RöFo - Fortschritte auf dem Gebiet der R 12/2002; 174(11):1408-14. · 2.76 Impact Factor -
Article: [Is a dynamic MRI examination of the pancreas still necessary?].
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ABSTRACT: Evaluation of the diagnostic potential of a dynamic MR examination of the pancreas. Retrospective study on 49 patients who underwent MRI of the pancreas (2 insulinomas, 2 cystadenomas, 19 pancreatic carcinomas, 26 patients with chronic pancreatitis). Interpretation was done in two steps: Initial evaluation of T2-weighted TSE-sequences, T1-weighted gradient echo sequences before and after injection of Gadolinium-DTPA i. v. Afterwards, additional evaluation of a dynamic contrast-enhanced MRI series of the pancreas with four dynamic scans. Dynamic MR examination of the pancreas is useful in case of insulinomas. However, in case of pancreatic cancer an additional dynamic MR examination of the pancreas does not provide further clinically relevant information. In patients with a suspicion of pancreatic cancer, the injection of contrast material should preferably be used for the performance of a contrast-enhanced MR angiography at the expense of a dynamic MR examination.RöFo - Fortschritte auf dem Gebiet der R 05/2002; 174(4):433-6. · 2.76 Impact Factor -
Article: [Follow-up in patients with head and neck tumors: evaluation of CT criteria for local tumor recurrence].
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ABSTRACT: Aim of this study was to evaluate morphologic criteria for diagnosis of locally recurrent head and neck tumors in helical CT. Retrospective study, 44 examinations with radiologically abnormal findings were re-read by two radiologists; findings were analysed and correlated with histological diagnosis and clinical findings. 25 cases of local tumor recurrence were confirmed histologically. The accuracy of helical-CT in our preselected examinations for a local tumor recurrence was 93.5 %, the specificity 83.3 %. But 13/44 cases showed radiologically equivocal findings, among them 6 tumor recurrences. The most common characteristics of the 25 proven tumor recurrences were: contrast medium enhancement (96 %), increased volume in comparison to previous examination (92 %), inhomogenity (72 %); however contrast medium-enhancement and increasing volume were also seen in 68.4 % and 63.1 % of the benign changes. Contrast medium enhancement and increasing volume are criteria with a high sensitivity but low specifity in predicting a local tumor recurrence in head and neck cancer.Laryngo-Rhino-Otologie 11/2001; 80(10):563-8. · 0.97 Impact Factor -
Article: Improving the detectability of focal liver lesions on T2-weighted MR images: ultrafast breath-hold or respiratory-triggered thin-section MRI?
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ABSTRACT: The purpose of this study was to determine whether a respiratory-triggered (RT) T2-weighted turbo spin-echo (TSE) sequence with thin section can improve the detectability of focal liver lesions compared to a breath-hold (BH) T2-weighted TSE sequence. In 25 patients an RT TSE with 8-mm sections (8-TSE RT) and 5-mm sections (5-TSE RT) and a BH TSE sequence with 8-mm sections (8-TSE BH) were performed. Forty-one focal liver lesions (mean: 1.8 +/- 1.2 cm; 14 lesions < or =1 cm; 27 lesions >1 cm) were evaluated. The 5-TSE RT was significantly better in lesion detection compared to the 8-TSE BH sequence for all sizes of lesions (40/41 vs. 33/41; P = 0.014). For lesions >1 cm no relevant differences in the detection rate of the sequences were found (8-TSE RT, 26/27; 5-TSE RT, 26/27; 8-TSE BH, 25/27), for lesions < or =1 cm the 5-TSE RT provided significantly better sensitivity than the 8-TSE BH (14/14 vs. 8/14, P = 0.015). The results of this study suggest that lesion detection could be significantly improved by using an RT TSE sequence with thin sections compared with a BH TSE sequence.Journal of Magnetic Resonance Imaging 08/2001; 14(2):128-33. · 2.70 Impact Factor -
Article: [Value of selective MIP reconstructions in respiratory triggered 3D TSE MR-cholangiography on a workstation in comparison with MIP standard projections and single-shot MRCP].
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ABSTRACT: Comparison of anatomical visualisation and diagnostic value of selective MIP reconstructions of respiratory triggered 3D-TSE-MRCP versus standard MIP reconstructions and single-shot MRCP. 50 patients with pancreaticobiliary disease were examined at 1.5 Tesla (ACS NT II, Philips Medical Systems) using a breath-hold single-shot (SS) and a respiratory triggered 3D-TSE-MRCP technique in 12 standard MIP projections. Additional selective MIP reconstructions with different slice thickness (2, 4, 10 cm) and projections were performed on a workstation. Visualization of the pancreaticobiliary system and the diagnostic value of the examinations were analysed. Single-shot and 3D-TSE in standard projections showed comparable anatomical visualisation. On selective MIP reconstructions the biliary system (SS p < 0.002; 3D-TSE p < 0.000) and the periampullary region (SS p < 0.000; 3D-TSE p < 0.003) were more clearly seen than on SS and standard MIP reconstructions. Furthermore, superior visualisation of the pancreatic duct could be achieved with additional selective MIP reconstructions in contrast to standard MIP (p < 0.003). Sensitivity and diagnostic accuracy showed superior results for selective and standard MIP reconstructions, but no significant differences between the three techniques were found. SS and standard MIP reconstructions showed comparable anatomical visualisation. Selective MIP postprocessing on a workstation offers a better visualisation of the pancreaticobiliary system and is useful for detecting pathological alterations.RöFo - Fortschritte auf dem Gebiet der R 05/2001; 173(5):416-23. · 2.76 Impact Factor -
Article: [Incidence and significance of small focal liver lesions in MRI].
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ABSTRACT: Analysis of the frequency and significance of small focal liver lesions (< or = 2 cm) detected on MRI in the presence or absence of a history of malignancy. 628 MRI examinations of the liver performed during 1994-1996 were evaluated. The inclusion criterion into the study was the detection of a focal liver lesion with a size < or = 2 cm. The frequency, the size, the diagnostic proof, and the differential diagnosis of the focal liver lesions were analysed with regard to the patients history of a known malignant tumor. Overall, 179 of the 628 patients (28.5%) had focal liver lesions < or = 2 cm (n = 338). 58.9% of the lesions could be classified based upon follow-up studies by ultrasound, CT or MRI, or by biopsy. The remaining 41.1% of the lesions could not be classified due to the absence of follow-up examinations. 57.3% of all proven lesions were benign and 42.7% were malignant. A history of a malignant tumor was present in 76.7% of all patients with small liver lesions; however, lesions were benign in these patients in 50.6% of the cases. In patients with no known history of a malignancy, 75% of the lesions were benign and 25% were malignant. However, these malignant lesions were in 10/11 cases hepatocellular carcinomas in patients with liver cirrhosis. Even in the presence of a history of a malignant tumor, about 50% of the detected small liver lesions on MRI are benign. In the absence of a tumor history the probability of a small malignant liver lesion is very low, if the patients does not have liver cirrhosis where small hepatocellular carcinomas can be present.RöFo - Fortschritte auf dem Gebiet der R 05/2001; 173(5):424-9. · 2.76 Impact Factor -
Article: [Space-occupying lesion in the left epigastric area. Gastric stromal tumor].
Der Radiologe 04/2001; 41(3):303-4. · 0.61 Impact Factor -
Article: Detection of thrombosis in the portal venous system: comparison of contrast-enhanced MR angiography with intraarterial digital subtraction angiography.
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ABSTRACT: To determine whether intraarterial digital subtraction angiography (DSA) can be replaced by contrast material-enhanced magnetic resonance (MR) angiography in the assessment of patency or thrombosis of the portal venous system in patients with portal hypertension. Thirty-six patients with portal hypertension underwent contrast-enhanced MR angiography and intraarterial DSA for assessment of the portal venous system. The images were evaluated for vessel patency or thrombosis of the portal, splenic, or superior mesenteric vein. Of the 101 vessels evaluated, 42 were thrombosed. Overall sensitivity, specificity, and accuracy for the detection of thrombosis were 100%, 98%, and 99%, respectively, for MR angiography and 91%, 100%, and 96%, respectively, for DSA; differences between the imaging methods were not statistically significant. Only in four patients with six vessels (6%) were there discordant findings between MR angiography and DSA. Noninvasive contrast-enhanced MR angiography has the potential to replace intraarterial DSA as the standard method to assess the whole portal venous system.Radiology 08/2000; 216(1):86-92. · 5.73 Impact Factor -
Article: [The pathological/MR tomographic correlation and differential diagnosis of malignant kidney tumors].
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ABSTRACT: Evaluation of malignancy criteria in MRT of kidney tumors in correlation with the histopathological findings. 41 patients with suspected malignant kidney tumors were examined using a T1 SE sequence (TR/TE 300/10 ms) before and after i.v. administration of 0.1 mmol/kg Gd-DTPA and a T2 SE sequence (TR/TE 5500/150 ms). The results were correlated with the pathological findings. 38 malignant tumors were found: 29 renal cell carcinomas (RCC), 13 with solid growth, 11 with tubulopapillary growth, and three with mixed growth forms, one cystic RCC, and one chromophobic RCC, in addition, 6 urothelial carcinomas and three other malignomas. Typical MRT criteria for RCC were an inhomogeneity of the tumor with regions of slightly increased signal intensity on the T1-weighted image (59%) and regions with reduced signal intensity on the T2-weighted image (96%) as compared with renal parenchyma; these were due to histomorphological hemorrhage and hemosiderin deposits, respectively. A further criterion for RCC was a hypointense pseudocapsule in the T2 TSE sequence in 79% of the cases. The low-signal nature of RCC in the T2-weighted image correlates with hemorrhage and hemosiderin deposits. The detection of a pseudocapsule is useful in the differential diagnosis of solid tumors in the kidney.RöFo - Fortschritte auf dem Gebiet der R 09/1999; 171(2):106-12. · 2.76 Impact Factor -
Article: Evaluation of different models of experimentally induced liver cirrhosis for MRI research with correlation to histopathologic findings.
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ABSTRACT: Three models of experimentally induced liver cirrhosis were evaluated for MRI research on chronic liver disease. The influence of different histopathologic changes in liver fibrosis and cirrhosis on relaxation times and signal intensities was studied in vitro and in vivo. Liver fibrosis and cirrhosis in rats was induced by oral or subcutaneous administration of carbon tetrachloride (CCl4) or by thioacetamide (TAA) in drinking water. On histology, the degree of liver fibrosis and cirrhosis, fatty infiltration, iron accumulation, and inflammatory changes were measured semiquantitatively. The amount of connective tissue was quantitatively determined by morphometry. The results were correlated with T1 and T2 relaxation times and signal intensities of the liver studied in vitro by relaxometry and in vivo by MRI. In both groups with CCl4 administration, histology revealed different degrees of liver fibrosis and cirrhosis. Subcutaneous injection of CCl4 also resulted in increased fatty infiltration. On the contrary, TAA produced complete liver cirrhosis in all animals. Overall, there was a good correlation between the liver T2 relaxation time and the amount of connective tissue in liver fibrosis and cirrhosis. However, the degree of liver fibrosis and cirrhosis was also strongly correlated with the degree of inflammatory changes. In the group with CCl4 administration, there was a good correlation between the fatty infiltration and the T1 relaxation time, as well as with the liver signal intensity on the T1-weighted gradient echo sequence. An increased iron accumulation was also correlated with the degree of liver fibrosis/cirrhosis; however, there was no significant influence of the iron on relaxation times or signal intensities. The TAA model is easier to perform and more reliable in liver cirrhosis induction than the CCl4 models. Although there is a positive correlation between the T2 relaxation times and the degree of liver fibrosis/cirrhosis, this probably results from the associated inflammatory changes and is not caused by the increased amount of connective tissue.Investigative Radiology 06/1999; 34(5):360-6. · 4.59 Impact Factor -
Article: [The MRT of focal liver lesions: the value of gadolinium-enhanced dynamic studies of the whole organ with a fast 3D-turbo-gradient echo sequence].
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ABSTRACT: To determine the value of a dynamic Gd-enhanced ultrafast T1-weighted 3D-turbo-gradient-echo sequence (3D-TFE) in the detection and characterization of focal liver lesions. 51 patients with 124 focal liver lesions (35 hemangiomas, 30 HCC, 24 metastases, 22 cysts, 5 FNH/adenoma, 8 other lesions) were examined using a 1.5 T system. The dynamic 3D-TFE sequence, achieving 40 slices with a thickness of 4.5 mm in a 17-s breath-hold, was compared with a fat-suppressed T2-weighted fast-spin-echo sequence (TSE SPIR), unenhanced and Gd-enhanced T1-weighted spin-echo sequences (SE), and a T1-weighted gradient-echo sequence (FFE). On 3D-TFE images more lesions (107/124) were identified than on T1-weighted SE (101/124) and T1-weighted FFE images (106/124), but less compared to T2-weighted TSE SPIR images (115/124). The 3D-TFE-sequence provided additional information in 65/107 (61%) detected lesions by delineating the dynamic enhancement pattern, most valuable in patients with HCCs in 90%. On dynamic 3D-TFE images more lesions could be depicted than on conventional T1-weighted SE and T1-weighted FFE images. Visualization of the dynamic enhancement pattern provided additional information for tumor characterization in 61% of the detected lesions on the 3D-TFE images.RöFo - Fortschritte auf dem Gebiet der R 05/1999; 170(4):351-7. · 2.76 Impact Factor -
Article: Enhanced tumor detection in the presence of liver cirrhosis: experimental study on the diagnostic value of a superparamagnetic iron oxide MR imaging contrast agent (NSR 0430).
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ABSTRACT: The purpose of this study was to determine the diagnostic value of the superparamagnetic iron oxide NSR 0430 for the detection of focal liver lesions in the presence of advanced cirrhosis. Cirrhosis and growth of cholangiofibromas were induced in 22 rats by administration of thioacetamide. Sixteen non-cirrhotic animals served as controls. T1 and T2 relaxation times of liver and tumor tissue of 12 animals were measured spectroscopically. In 10 animals in vivo MRI was performed before and 1 hour after contrast administration, and then the tumor-to-liver contrast-to-noise ratio (CNR) was calculated. All specimens were evaluated histologically. After contrast administration, T1 and T2 values of liver tissue showed a significant decrease of 18% (P = 0.01) and 31% (P = 0.009), respectively, whereas relaxation times of tumor tissue did not change. On precontrast turbo spin-echo images, 40 tumors could be identified; after contrast administration, 95 lesions were visible. CNR increased significantly after contrast administration by 297% at a TE of 50 msec and by 254% at a TE of 90 msec. In conclusion, our in vitro and in vivo results demonstrate that administration of NSR 0430 substantially improves liver-to-tumor CNR and lesion detection on T2-weighted magnetic resonance images even in the presence of severe cirrhosis.Journal of Magnetic Resonance Imaging 03/1999; 9(2):251-6. · 2.70 Impact Factor -
Article: Imaging for diagnosis of hepatocellular carcinoma.
Digestion 08/1998; 59 Suppl 2:75-7. · 2.05 Impact Factor -
Article: [MRI, CT and CT arterial portography in the diagnosis of malignant liver tumors in liver cirrhosis].
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ABSTRACT: To determine the value of magnetic resonance imaging (MRI), computed tomography (CT) and CT arterial portography (CTAP) in detecting malignant liver lesions in cirrhosis patients. The radiological examinations (CT, MRI and CTAP) of 47 patients suffering from cirrhosis having undergone an orthotopic liver transplantation (OLTX) were analysed retrospectively. The number of detected liver lesions was compared with the results of the histopathological findings after OLTX. 13/21, 11/18 and 7/12 of the malignant lesions were detected by MRI, CT and CTAP respectively. In MRI one false positive case was shown, two in CT and three in CTAP. Almost the same lesions were identified by all three procedures. The examination of the liver with MRI and CT and CTAP did not bring additional information. Most of the lesions that were missed were less than 2 cm in diameter. The rate of detection of HCC in patients with cirrhosis was about 60%. MRI and CT yielded similar results.RöFo - Fortschritte auf dem Gebiet der R 07/1998; 168(6):567-72. · 2.76 Impact Factor -
Article: [Symptomatic heterotopic splenic tissue in the adrenal gland area].
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ABSTRACT: We report on a 33-year-old man with symptomatic heterotopic suprarenal splenic tissue. Heterotopic splenic tissue can often be found after posttraumatic splenectomy. It is a result of autotransplantation induced by trauma (splenosis). Additionally it can grow during embryogenic development. Such an accessory spleen is found in 10-44% of all autopsies. In this case report the patient was treated by resection due to increasing flank pain and suspected neoplasm.Aktuelle Radiologie 06/1998; 8(3):135-7.
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Institutions
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1990–2005
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Rheinische Friedrich-Wilhelms-Universität Bonn
- Radiologische Klinik
Bonn, North Rhine-Westphalia, Germany
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