U Mödder

Heinrich-Heine-Universität Düsseldorf, Düsseldorf, North Rhine-Westphalia, Germany

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Publications (453)654.86 Total impact

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    ABSTRACT: OBJECTIVE: To get insight into the nature of magnetic resonance (MR) white matter abnormalities of patients with classic maple syrup urine disease (MSUD) under diet control. METHODS: Ten patients with classic MSUD and one with a severe MSUD variant (mean age 21.5 ± 5.1 years) on diet and 11 age and sex-matched healthy subjects were enrolled. Apart from standard MR sequences, diffusion weighted images (DWI), diffusion tensor images (DTI), and magnetization transfer images (MT) were obtained and comparatively analyzed for apparent diffusion coefficient (ADC), tensor fractional anisotropy (FA) and MT maps in 11 regions of interest (ROI) within the white matter. RESULTS: In MSUD patients DWI, DTI and FA showed distinct signal changes in the cerebral hemispheres, the dorsal limb of internal capsule, the brain stem and the central cerebellum. Signal intensity was increased in DWI with a reduced ADC and decreased values for FA. MT did not reveal differences between patients and control subjects. CONCLUSION: Signal abnormalities in the white matter of adolescents and young adults under diet control may be interpreted as consequence of structural alterations like dysmyelination. The reduced ADC and FA in the white matter with preserved MT indicate a reduction in fiber tracks.
    Journal of Inherited Metabolic Disease 01/2013; · 4.07 Impact Factor
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    ABSTRACT: □ FallbeschreibungEin 25jähriger türkischer Patient stellte sich mit einer seit fünf Jahren bestehenden „Schwellung” im Bereich, der Sprunggelenke beidseitig vor, die zuvor als HLA-B27-negative Spondylarthropathie mit peripherer Gelenkbeteiligung klassifiziert worden war. Die Beschwerdesymptomatik zeigte auf unterschiedliche Therapieversuche ein nur unzureichendes Ansprechen. Nach serologischer und radiologischer Diagnostik wurde als Ursache der Arthropathie eine β-Thalassaemia minor diagnostiziert. □ DiskussionKlinik, Diagnose und Differentialdiagnostik der β-Thalassaemia minor werden diskutiert. □ Case ReportA 25-year-old Turkish patient presented with a “swelling” of the ankles which now persisted for 5 years. He had previously been diagnosed as having HLA-B27 negative spondylarthropathy with peripheral joint involvement. The symptoms failed to respond to different therapies. Serological markers and radiological procedures revealed β-thalassemia minor. □ DiscussionSymptoms, diagnostic procedures and differential diagnostic options are discussed.
    04/2012; 95(1):40-43.
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    ABSTRACT: Medical curricula are currently being reformed in order to establish superordinated learning objectives, including, e.g., diagnostic, therapeutic and preventive competences. This requires a shifting from traditional teaching methods towards interactive and case-based teaching concepts. Conceptions, initial experiences and student evaluations of a novel radiological course Co-operative Learning In Clinical Radiology (CLICR) are presented in this article. A novel radiological teaching course (CLICR course), which combines different innovative teaching elements, was established and integrated into the medical curriculum. Radiological case vignettes were created for three clinical teaching modules. By using a PC with PACS (Picture Archiving and Communication System) access, web-based databases and the CASUS platform, a problem-oriented, case-based and independent way of learning was supported as an adjunct to the well established radiological courses and lectures. Student evaluations of the novel CLICR course and the radiological block course were compared. Student evaluations of the novel CLICR course were significantly better compared to the conventional radiological block course. Of the participating students 52% gave the highest rating for the novel CLICR course concerning the endpoint overall satisfaction as compared to 3% of students for the conventional block course. The innovative interactive concept of the course and the opportunity to use a web-based database were favorably accepted by the students. Of the students 95% rated the novel course concept as a substantial gain for the medical curriculum and 95% also commented that interactive working with the PACS and a web-based database (82%) promoted learning and understanding. Interactive, case-based teaching concepts such as the presented CLICR course are considered by both students and teachers as useful extensions to the radiological course program. These concepts fit well into competence-oriented curricula.
    Der Radiologe 11/2011; 51(11):969-70, 973-7. · 0.47 Impact Factor
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    ABSTRACT: Hepatocellular carcinoma (HCC) ranks sixth regarding prevalence and third regarding mortality among malignant tumours worldwide. The aim of the present study was to determine changes of clinical-epidemiological parameters and survival rates during two decades. A total of 441 consecutive patients with HCC admitted to the University Clinic Düsseldorf between January 1988 and December 2007 were included. For comparison, this time period was divided into two decades (1988 - 1997 and 1998 - 2007). The number of newly diagnosed HCCs has tripled in the years 1998 - 2007 compared to the years 1988 - 1997. HCV-associated HCCs increased from 28 % in the years 1988 - 1997 to 38 % (p < 0.05) in the years 1998 - 2007. Tumour size, Okuda and BCLC stages decreased during the observation period (both p < 0.001 and p < 0.05). Median overall survival improved during the observation period from 6 [95 % CI: 4.83 - 7.17] to 9 months ]95 % CI: 7.31 - 10.69]; p < 0.0001) as did the 1-year and 5-year survival rates from 22 % to 42 % (p < 0.019) and from 0 % to 9 % (p < 0.001), respectively. The proportion of treated patients compared to patients with best supportive care as well as the proportion of patients receiving a multimodal therapy compared to patients with a single treatment regimen increased in the second decade (55 % vs. 79 %: p < 0.005; 5.4 % vs. 23 %: p < 0.0001). Multimodal therapy was an independent predictor for prolonged survival in a multivariate analysis including Child-Pugh score, BCLC stage, tumour size, and gender (odds ratio 2,77; 95 % CI: 1.44 - 5.31). Improved screening as well as broader and improved treatment options may have contributed to the increasing survival rates.
    Zeitschrift für Gastroenterologie 06/2011; 49(6):720-7. · 1.41 Impact Factor
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    ABSTRACT: The diagnostic accuracies of contrast-enhanced sonography and hepatobiliary contrast-enhanced MRI of the liver in evaluating focal liver lesions in patients with liver cirrhosis were compared. In 33 patients (25 men, 8 women, mean age 63.2 ± 11.2 years) MRI of the liver using Gd-EOB-DTPA (Primovist®, Bayer Schering Pharma, Berlin) was performed. Axial T(2)-weighted, unenhanced T(1)-weighted and enhanced T(1)-weighted scans during arterial, portal venous and late phases were acquired, followed by coronary T(1)-weighted and axial fat-suppressed T(1)-weighted scans 15 minutes post contrast application. In all patients within 4 weeks contrast-enhanced sonography using sulfur hexafluoride microbubbles (SonoVue®, Nycomed, Germany) was obtained. Cirrhosis of the liver was related to viral infection in 45.4% and to alcoholism in 39.4%. All hepatic lesions were confirmed by histologic examination. Sensitivity and specificity of MRI were 90.2% and 83.3%, compared to contrast-enhanced sonography with 92.7 % and 50 %, respectively. Positive and negative predictive values were 97.4% and 55.5 % for MRI and 90.5% and 50% for contrast-enhanced sonography, respectively. In this retrospective study MRI using Gd-EOB-DTPA as well as contrast-enhanced sonography using sulfur hexafluoride microbubbles gave excellent results in detecting HCC in patients suffering from liver cirrhosis. Although the specificity was higher for MRI, the accuracy showed no significant difference between these two imaging techniques.
    Zeitschrift für Gastroenterologie 01/2011; 49(1):23-9. · 1.41 Impact Factor
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    ABSTRACT: Evaluation of subjective image quality in dose-reduced multi-detector CT (MDCT) of paranasal sinuses using a 2D non-linear adaptive post-processing filter (2D-NLAF). MDCT of paranasal sinuses was simulated using a human head phantom at a Somatom Sensation Cardiac 64 (Siemens, Erlangen). At constant collimation (64 × 0.6 mm) und pitch (p = 1), the tube current (50, 100, 200 mAs) and tube potential (80, 100, 120 kVp) were modified. The radiation exposure was represented by CTDIvol. Four independent blinded radiologists evaluated the image quality of axial 2 mm images and coronal reformations concerning the assessment of "fractures" and "soft tissue processes". The subjective image quality of original and post-processed images using a 2D-NLAF (SharpViewCT®, Sweden) was graded on a 5-point scale ("1" excellent - "5" not adequate) and compared. Compared to the protocol with the best image quality (120kVp/ 200 mAs) 2D-NLAF led to a significant improvement in the subjective image quality at 100 kVp/ 100 mAs (score "1.4" with filter versus "2.2" without) and 120 kVp/ 50 mAs ("1.6" versus "2.0") (p < 0.03) particularly for high contrasts ("fractures", p < 0.001). In "soft tissue processes", 2D-NLAF provided improved quality from "2.1" to "1.4" (p < 0.04) at 100 kVp/ 100 mAs. Down to a CTDIvol of 8 mGy, the image quality was rated "good", and down to 5 mGy "diagnostic". The phantom study indicates a dose reduction potential in MDCT of paranasal sinuses up to 58% compared to a standard dose protocol using a 2D-NLAF without an essential loss of image quality. 2D-NLAF is particularly effective at 100 kVp/ 100 mAs and 120 kVp/ 50 mAs.
    RöFo - Fortschritte auf dem Gebiet der R 11/2010; 182(11):973-8. · 2.76 Impact Factor
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    ABSTRACT: To determine whether MR bone marrow findings in Gaucher patients may help to identify patients at high risk of developing severe Gaucher bone complications exemplified by avascular necrosis (AVN) of the femoral head. MR images were obtained in 63 Type I Gaucher patients through a standard protocol using coronal T 1 and T 2-weighted sequences of the lower extremities. The location and extent of infiltrated marrow was established using a semi-quantitative MRI scoring method (Düsseldorf Gaucher score, DGS) and the morphological pattern of bone marrow involvement determined (whether homogeneous type A or non-homogeneous type B). The active marrow process with bone edema and AVN of the femoral head were also analyzed. Bone marrow involvement was observed in femoral sites more than in tibial sites. A high DGS was significantly correlated with type B morphology and femoral AVN (both p < 0.0001). Splenectomized patients showed a significantly higher Düsseldorf Gaucher score and type B morphology than non-splenectomized patients (both p < 0.05). AVN was seen in 46 % of patients with type B morphology versus 3 % in type A morphology (p < 0.0001). DGS and morphology of bone marrow involvement were not significantly correlated with active marrow processes. Type B marrow morphology and extensive marrow packing were significantly associated with AVN of the femoral head (both p < 0.0001). These patterns are considered predictive and may be employed in a disease management context to alert physicians to the need for urgent therapeutic measures.
    RöFo - Fortschritte auf dem Gebiet der R 11/2010; 182(11):979-85. · 2.76 Impact Factor
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    ABSTRACT: The assessment of the radiological response of recurrent glioma is based on the Macdonald or RECIST criteria 8 to 10 weeks from the start of treatment. Magnetic resonance imaging using an apparent diffusion coefficient map may provide an earlier measure for predicting the response to therapy of recurrent glioma. Twelve patients with recurrent high-grade glioma were enrolled in a feasibility study of pretreatment MRI on day 1, intra-treatment MRI in week 3, and post-treatment MRI in week 12. Prognostically relevant ADC values (ADCprog) of each recurrent glioma at 3 weeks were calculated as a function of their pre- and intra-therapy ADC values (ADCpre - ADCintra = ADCprog). Because we hypothesized that smaller ADC values correlate with less Brownian motion of water molecules in the extracellular space and that a higher cell density may restrain this water diffusion, we set smaller ADC values at a second time point as "progressive disease" (PD) and higher ADC values as "partial response" (PR). A change in ADCprog of less than 10 × 10⁻⁶mm² /sec was set as "stable disease" (SD). The ADCprog values were always calculated before the final scan after 3 months was performed. The readers were blinded to the future development of the tumor. In 10 of the 12 patients we could correctly predict the tumor response to chemotherapy. One patient died before the three-month control, and one recurrent glioma did not develop as predicted. ADC mapping is found to predict patient response at 3 weeks from the start of treatment, revealing that early changes in tumor diffusion values could be used as a prognostic indicator also for chemotherapeutically treated recurrences of high-grade glioma.
    RöFo - Fortschritte auf dem Gebiet der R 10/2010; 182(10):868-72. · 2.76 Impact Factor
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    ABSTRACT: The signal of diffusion-weighted imaging of the human kidney differs from the signal in brain examinations due to the different microscopic structure of the tissue. In the kidney, the deviation of the signal behavior of monoexponential characteristics is pronounced. The aim of the study was to analyze whether a mono- or biexponential or a distribution function model fits best to describe diffusion characteristics in the kidney. To determine the best regression, different statistical parameters were utilized: correlation coefficient (R(2)), Akaike's information criterion, Schwarz criterion, and F-test (F(ratio)). Additionally, simulations were performed to analyze the relation between the different models and their dependency on signal noise. Statistical tests showed that the biexponential model describes the signal of diffusion-weighted imaging in the kidney better than the distribution function model. The monoexponential model fits the diffusion-weighted imaging data the least but is the most robust against signal noise. From a statistical point of view, diffusion-weighted imaging of the kidney should be modeled biexponentially under the precondition of sufficient signal to noise.
    Magnetic Resonance in Medicine 08/2010; 64(2):616-22. · 3.27 Impact Factor
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    ABSTRACT: The spatial and temporal relations between regional cerebral blood flow (rCBF) and brain volume (rVOL) changes in incipient and early Alzheimer's dementia (AD) are not fully understood. The participants comprised 30 subjects with mild cognitive impairment (MCI) and 15 with mild AD who were examined using structural and perfusion-weighted magnetic resonance imaging (MRI) at 1.5 Tesla. Hippocampus and amygdala volumes were measured by manual volumetry. A region-of-interest co-localisation method was used to calculate rCBF values. DNA samples were genotyped for apolipoprotein E (APO E). In comparisons of AD with MCI, rCBF was reduced in the posterior cingulum only, while profound rVOL reductions occurred in both right and left amygdala and in the right hippocampus, and as a trend, in the left hippocampus. Brain volumes of the hippocampus and the amygdala were uncorrelated with the respective rCBF variables in both MCI and AD. Hippocampal but not amygdalar volumes were associated with presence of one or two APOE epsilon4 alleles in MCI and mild AD, while there was no association of APOE epsilon4 allele with rCBF. These data support earlier indications that rCBF and rVOL changes are at least partly dissociated in the early pathogenesis of AD and heterogeneously associated with the APOE risk allele. The data also support the concept of functional compensatory brain activation and the diaschisis hypothesis as relevant in incipient and early AD.
    Psychiatry Research 07/2010; 183(1):44-51. · 2.68 Impact Factor
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    ABSTRACT: Earlier evidence indicates that regional cerebral volume (rVOL) and blood flow (rCBF) variables carry independent information on incipient and early Alzheimer's disease (AD) and combining these modalities may increase discriminant performance. We compared single variables and combinations regarding their power for optimizing diagnostic accuracy. Twelve cognitively normal elderly controls (CN), 30 subjects with mild cognitive impairment (MCI) and 15 with mild AD were examined by structural and perfusion-weighted magnetic resonance imaging (MRI) in single sessions at 1.5 Tesla. rVOLs were measured by manual volumetry, and rCBFs were calculated with a ROI-based co-localization technique. Applying single MRI variables for the differentiation of AD versus CN, the area under curve (AUC) of receiver operating characteristic curves (ROCCs) was highest for rVOL variables (maximum of 0.972 for right amygdala). A composite marker selected and weighted by logistic regression containing left amygdalar rCBF, left hippocampal and right amygdalar rVOLs gave a diagnostic accuracy for AD versus CN of 100%. Internal cross-validation revealed a reliability of 88.9%. Whilst external revalidation is mandatory employing a naturalistic sample containing disease controls, our phase I/II findings demonstrate that deducing composite markers from multimodal MRI acquisitions can optimize diagnostic accuracy for AD.
    European Journal of Neurology 04/2010; 17(12):1437-44. · 4.16 Impact Factor
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    ABSTRACT: To evaluate non-enhanced 3D MR angiography using turbo spin echo (TSE) imaging with non-selective refocusing pulses (NATIVE SPACE MRA) for the visualization of the arteries of the lower extremity. Three-station imaging (iliac arteries, femoral arteries, arteries of the lower leg) was performed in 8 healthy volunteers and 3 patients with peripheral artery disease (PAD) using a 1.5 T MR scanner. In 8 healthy volunteers, 4 different acquisition schemes were performed with the following imaging parameters: S 1: acquisition with every heartbeat (RR = 1), spoiler gradient of 25 % (SG = 25 %); S 2: RR = 1, SG = 0 %; S 3: RR = 2, SG = 25 %; S 4: RR = 2, SG = 0 %. The subjective image quality on a 4-point-scale (4 = excellent to 1 = not diagnostic) and relative SNR were assessed. In 3 patients with peripheral artery disease (PAD), SPACE MRA was performed for assessment of stenosis. The mean subjective image quality was significantly lower for the iliac arteries compared to the femoral arteries and arteries of the lower leg (p < 0.0001). The subjective image quality for acquisition scheme S 1 was significantly lower than the image quality for S 3 and S 4 for the iliac arteries (p < 0.01), while the subjective image quality for acquisition scheme S 2 was significantly lower than S 3 and S 4 for the femoral arteries and the arteries of the lower leg (p < 0.01). The relative SNR was significantly higher for acquisition schemes S 3 and S 4 as compared to S 1 and S 2 (p < 0.0001) for all regions. SPACE MRA disclosed 7 significant stenoses in 3 PAD patients. ECG-gated SPACE MRA is a promising imaging technique for non-enhanced assessment of the arteries of the lower extremity.
    RöFo - Fortschritte auf dem Gebiet der R 04/2010; 182(10):861-7. · 2.76 Impact Factor
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    ABSTRACT: Opioids are applied to augment visualization of the biliary system in MR cholangiopancreatography (MRCP) to take advantage of a side effect, the constriction of the sphincter of Oddi. This prospective study was performed to determine the effect of IV low-dose morphine on image quality and bile duct delineation in MRCP. Fifteen healthy volunteers and 15 consecutive patients underwent MRCP on a 1.5-T MRI scanner. Strongly T2-weighted 3D single-shot fast spin-echo (SSFSE) sequences were acquired before and 10 minutes after IV administration of morphine (0.04 mg/kg of body weight; mean +/- SD, 2.9 +/- 0.5 mg). Maximum intensity projections were reconstructed from the SSFSE sequence data. Image quality was rated by two independent radiologists using a 4-point scale (1 = excellent, 4 = not diagnostic). Delineation of segmental and subsegmental intrahepatic bile duct orders before and after morphine administration was compared. Volumetry of the common bile duct (CBD) was performed using electronic measurements (AngioTux software, ECCET image processing system). IV morphine did not significantly improve subjective image quality of the extra- and intrahepatic bile ducts (mean image quality score before vs after morphine administration, 2.3 vs 2.0) or delineation of the intrahepatic bile duct orders. The volume of the CBD remained constant after morphine administration (mean CBD volume before vs after morphine administration, 14.1 vs 13.6 mL). Notable side effects of morphine were seen in two young healthy female volunteers. IV-administered low-dose morphine seems to have no essential influence on image quality or delineation of the bile duct system in MRCP. Therefore, the general advice to perform morphine-augmented MRCP should be discussed critically.
    American Journal of Roentgenology 02/2010; 194(2):W171-5. · 2.90 Impact Factor
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    ABSTRACT: To assess rotation deficits, asphericity of the femoral head and localisation of cartilage damage in the follow-up after slipped capital femoral epiphysis (SCFE). Magnetic resonance imaging studies were obtained in adult patients with a history of SCFE. A total of 35 hips after SCFE in 26 patients (mean age 24.1 +/- 6.5, mean follow-up 11.9 +/- 6.1 years) were evaluated. The control group comprised 20 healthy hips from 10 young adults with an average age of 23.9 +/- 3.7 years. The MR protocol included a T1-weighted sequence with a 3D volumetric interpolated breath-hold sequence and a radial 2D proton density-weighted sequence around the femoral neck. Images were evaluated for alpha angle and cartilage damage in five positions around the femoral head. Hip function was evaluated at the time of MRI and correlated with MRI results. Mann-Whitney U test and Spearman's correlation coefficient were used for statistical analysis. In the hips after SCFE alpha angles were significantly increased in the anterosuperior (74.1 degrees +/- 18.8 degrees ) and superior (72.5 degrees +/- 21.5 degrees ) positions and decreased in the posterior position (25.0 degrees +/- 7.2 degrees ). Cartilage damage was dominant in the anterosuperior and superior positions. Impaired rotation significantly correlated with increased anterosuperior, superior and posterosuperior alpha angles. The data support an anterosuperior and superior cam-type deformity of the femoral head-neck junction in the follow-up after SCFE. MRI after SCFE can be used to assess anterosuperior and superior alpha angles, since the anterior alpha angle by itself may underestimate asphericity and is not associated with rotation deficits.
    Skeletal Radiology 02/2010; 39(6):533-41. · 1.74 Impact Factor
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    ABSTRACT: The use of diffusion weighted magnetic resonance imaging (DWI) has been more and more extended to abdominal organs. In comparison to the human brain the tissue of the kidney shows considerably different microscopic structure, which must be considered in the calculating of the apparent diffusion constant (ADC). In most studies ADC is determined using a mono-exponential model. Due to the high vascularization in the kidney a bi-exponential approach is reasonable to allow for a differentiation between pure diffusion fraction and a fraction influenced by perfusion effects. In our work we analyzed whether the mono- or bi-exponential approach is more accurate from statistical point of view for in-vivo DWI of the kidney. For this purpose we acquired DWI in five healthy subjects. Further we simulated a DWI signal varying the value of the perfusion fraction to investigate the relation between the results of mono- and bi-exponential analysis. Besides we simulated a DWI signal at different signal to noise ratios to analyze the influence of noise on the ADC resulting from the mono- and bi-exponential approach. The statistical analysis of F-test, Akaike’s information criterion (AIC) and Schwarz criterion (FC) of the in-vivo data shows that the bi-exponential approach represents the “best regression” to determine ADC. In five in-vivo investigations 87% (F-test), 95 % (AIC) and 92% (SC) of the pixels possessed bi-exponential characteristics. The simulation of the DWI signal asserts increasing mono-exponential calculated ADC values with rising perfusion fraction within the tissue. Further our simulation shows that the variations of the mono-exponential results with increasing noise are less than that of bi-exponential approach. Keywordsdiffusion-MRI-kidney-bi-exponential-ADC
    01/2010: pages 119-122;
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182(02).
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182(08).
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.

Publication Stats

3k Citations
654.86 Total Impact Points

Institutions

  • 1988–2013
    • Heinrich-Heine-Universität Düsseldorf
      • Institut für Diagnostische und Interventionelle Radiologie
      Düsseldorf, North Rhine-Westphalia, Germany
  • 2002–2009
    • Universitätsklinikum Düsseldorf
      • Institut für Diagnostische und Interventionelle Radiologie
      Düsseldorf, North Rhine-Westphalia, Germany
    • University of Hamburg
      • Department of Diagnostic and Interventional Neuroradiology
      Hamburg, Hamburg, Germany
  • 2007
    • Stavanger University Hospital
      • Department of Radiology
      Stavanger, Rogaland Fylke, Norway
  • 1999
    • University of Leipzig
      • Klinik und Poliklinik für Diagnostische und Interventionelle Radiologie
      Leipzig, Saxony, Germany
  • 1980–1987
    • University of Cologne
      • Zoological Institute
      Köln, North Rhine-Westphalia, Germany