PJ Schäfer

University Medical Center Schleswig-Holstein, Kiel, Schleswig-Holstein, Germany

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Publications (67)176.14 Total impact

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    ABSTRACT: The hypothesis that covered stents are superior to bare-metal stents (BMS) in long femoropopliteal artery disease was tested. The one-year results of the VIASTAR trial revealed a patency benefit of covered stents in the treatment-per-protocol (TPP) analysis only. A prospective, randomized, single-blind, multicenter study evaluated 141 patients with symptomatic peripheral arterial disease (PAD) after treatment with heparin-bonded covered stents (VIABAHN(®) Endoprosthesis) or BMS. Clinical outcomes and patency rates were assessed at 1, 6, 12, and 24 months. Mean lesion length was 19.0 ± 6.3 cm in the VIABAHN(®) versus 17.3 ± 6.6 cm in the BMS group. The 24-month primary patency rates in the VIABAHN(®) and BMS group were: intention-to-treat 63.1 (95 % CI 0.52-0.76) versus 41.2 % (95 % CI 0.29-0.57; log rank p = 0.04) and TPP 69.4 (95 % CI 0.58-0.83) versus 40.0 % (95 % CI 0.28-0.56; log rank p = 0.004). Freedom from target-lesion-revascularization (TLR) was 79.4 (95 % CI 0.70-0.90) versus 73.0 % (95 % CI 0.63-0.85) for VIABAHN(®) versus BMS (log rank p = 0.37). For the TPP group in lesions ≥20 cm, the 24-month patency rates were 65.2 (95 % CI 0.50-0.85) versus 26.7 % (95 % CI 0.12-0.59; log rank p = 0.004) for VIABAHN(®) versus BMS, and freedom from TLR was 80.0 (95 % CI 0.68-0.94) versus 61.9 % (95 % CI 0.44-0.87; log rank p = 0.13). The ankle brachial index was 0.89 ± 0.18 versus 0.91 ± 0.17 (p = 0.76) at 24-month in the VIABAHN(®) versus the BMS group, respectively. At 24-month, this trial in PAD patients with long femoropopliteal lesions demonstrated a significantly improved primary patency rate for heparin-bonded covered stents compared to BMS, however, without a significant impact on clinical outcomes and TLR rate (Reg. Nr. ISRCTN48164244).
    CardioVascular and Interventional Radiology 12/2014; 38(1). DOI:10.1007/s00270-014-1024-9 · 1.97 Impact Factor
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    ABSTRACT: The hypothesis that endovascular treatment with covered stents has equal risks but higher efficacy than BMS in long femoro-popliteal artery disease was tested. While endovascular treatment of short SFA lesions revealed excellent results, efficacy in long lesions remains unsatisfactory. In a prospective, randomized, single-blind, multicenter study 141 patients with symptomatic PAD were assigned to treatment with heparin-bonded, covered stents (VIABAHN®, 72 patients) or BMS (69 patients). Clinical outcomes and patency rates were assessed at 1, 6, and 12-months. Mean lesion length was 19.0±6.3cm versus 17.3±6.6cm in the VIABAHN® versus BMS group. Major complications within 30-days were observed in 1.4%. The 12-months primary patency rates in the VIABAHN® and BMS group were: ITT 70.9% (95%CI, 0.58-0.80) and 55.1% (95%CI, 0.41-0.67; log rank p=0.11), TPP 78.1% (95%CI, 0.65-0.86) and 53.5% (95%CI, 0.39-0.65) (HR 2.23, 95%CI, 1.14-4.34; log rank p=0.009). In lesions ≥20cm (TASC D) the 12-months patency rate was significantly longer in VIA patients in the ITT-analysis (VIA 71.3% versus BMS 36.8%; p=0.01) and the TPP-analysis (VIA 73.3% versus BMS 33.3%; p=0.004). Freedom from target lesion revascularization was 84.6% for VIABAHN® (95%CI, 0.72-0.91) versus BMS 77.0% (95%CI, 0.63-0.85; p=0.37). The ankle-brachial index in the VIABAHN® group significantly increased to 0.94±0.23 (versus BMS 0.85±0.23; p<0.05) at 12-months. This randomized trial in symptomatic PAD patients who underwent endovascular treatment for long femoro-popliteal lesions demonstrated significant clinical and patency benefits for heparin-bonded covered stents compared to BMS in lesions ≥20cm and for all lesions in the TPP analysis. In the ITT analysis for all lesions, which however was diluted by 8.5% major protocol violations, the difference was not significant (Reg.Nr. ISRCTN48164244). Clinical trial ID: VIASTAR; http://www.controlled-trials.com/ISRCTN48164244; ISRCTN48164244.
    Journal of the American College of Cardiology 07/2013; 62(15). DOI:10.1016/j.jacc.2013.05.079 · 15.34 Impact Factor
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    ABSTRACT: Objective: To prospectively analyze duplex sonography, CTA, and MRA with respect to stenosis grading of the celiac trunk (TC) and the superior mesenteric artery (SMA), with DSA as the reference.Materials & Methods: 52 subjects were enrolled (mean age: 71). The image quality was graded: 1-insufficient, 2-bad, 3-moderate, 4-good or 5-excellent. Stenosis was graded: 1 (< 25 %), 2 (25 - < 50 %), 3 (50 - 75 %) or 4 (75 %). Two-sided chi-square tests were used to check for correlation of stenosis grading between modalities. The weighted Cohen's kappa was calculated to assess the strength of correlation. With a threshold of 50 % for non-relevant stenosis vs. relevant stenosis, the sensitivity, specificity, PPV, NPV, and accuracy were calculated.Results: The mean image quality was 3.8 ± 0.7, 3.1 ± 1.0, 4.4 ± 0.7, and 3.8 ± 0.9 for DSA, duplex sonography, CTA, and MRA, respectively. For both TC and SMA, stenosis grading reached a significant level of correlation between each noninvasive modality with DSA (p < 0.001, each). The weighted Cohen's kappa for duplex sonography/CTA/MRA was 0.94/0.93/0.74, respectively, for the TC and 0.64/0.91/0.56, respectively, for the SMA. Highest sensitivity/specificity/NPV/PPV/accuracy were found for CTA with 100 %/95 %/85 %/100 %/96 % for the TC and with na/98 %/na/100 %/98 %, respectively, for the SMA.Conclusion: CTA provided the best image quality, reached the highest level of agreement and significance in correlation in stenosis grading, and offered the best diagnostic accuracy.
    RöFo - Fortschritte auf dem Gebiet der R 06/2013; 185(7). DOI:10.1055/s-0033-1335212 · 2.76 Impact Factor
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    ABSTRACT: Background Breast cancer screening programs have been established worldwide and early detection of breast cancer has increased steadily. The most common way to confirm dignity of non-palpable and sonographically-occult suspicious findings on mammography is the stereotactically-guided vacuum-assisted breast biopsyPurposeTo compare two stereotactically guided vacuum-assisted breast biopsy systems measuring time effectiveness and quality of harvested material in clinical practice.Material and Methods One hundred and forty-six patients presenting with suspicious microcalcifications on mammography were included in the study. Biopsies were carried out with either the Mammotome(®) system (11-gauge and 8-gauge) or the ATEC(®) system (12-gauge and 9-gauge). Lesions with a diameter <15 mm on mammography were biopsied with 11-gauge or 12-gauge devices whereas lesions >15 mm were targeted with 8-gauge and 9-gauge. Mammotome(®) system 8-gauge device was used in 34 patients, the 11-gauge system in 37 patients. The ATEC(®) system 9-gauge system was used in 37 patients and 12-gauge in 38 patients. Time was taken, focusing on preparing the system, time of collecting the samples, preparing the samples, and cleaning the site. During the biopsies 24 samples were taken. The histologic quality of the tissue samples was judged by a pathologist in a blinded fashion according to a specimen grading classification concerning tissue fragmentation, artefacts, and the adequacy of the tissue for diagnosis.ResultsThe median overall time for the Mammotome(®) system was 879 s (11-gauge) and 934 s (8-gauge) and for the ATEC(®) system 671 s (12-gauge) and 673 s (9-gauge). The ATEC(®) system displays a significantly shorter overall time for small and large biopsy devices (U-test, P < 0.001). Concerning the mean time difference of the overall time comparing small and large systems the ATEC(®) system was 267.6 s faster using the small and 244.8 s faster using the large system. Comparing the histologic quality of tissue samples the Mammotome(®) system shows significantly higher values for the large and the small system (Chi-square test, P < 0.001).Conclusion Both biopsy systems meet all requirements for daily practice and confirm the diagnosis of suspicious microcalcifications. The ATEC(®) system was observed to be faster but this difference of about 250 s might not be relevant in daily practice. The Mammotome(®) system provides a better histologic quality of tissue samples.
    Acta Radiologica 01/2013; 54(2). DOI:10.1258/ar.2012.120420 · 1.35 Impact Factor
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    ABSTRACT: Purpose: To analyze the efficacy of interventions in acute dysfunctional hemodialysis fistulas, if intervention is performed immediately as recommended by European Best Practice Guidelines for Hemodialysis. Materials and Methods: Over 3 years, all (n = 280) patients with an acute dysfunctional hemodialysis fistula were immediately referred to angiography, irrespective of the time of day. Angiography and, if possible, interventional revision (n = 241) were performed. Three groups of interest were established: interventionalist's experience (high/low), time of day (routine hours: 7 am-4 pm/emergency hours: 4 pm-7 am), lesion type (stenosis/fibrosclerotic occlusion/thrombotic occlusion/combined stenosis+thrombotic occlusion). For statistical analysis corresponding success rates, chi-square tests (p < 0.025) and logistic regression analysis (p < 0.05) were calculated. Results: The total success rate was 62 % (149/241). The success rates were: interventionalist experience high/low 71 % (79/111)/54 % (70/130), p = 0.022; time of day routine/emergency hours 68 % (93/136)/53 % (56/105), p = 0.017; lesion type stenosis/fibrosclerotic occlusion/thrombotic occlusion/combined stenosis+occlusion 82 % (94/104)/39 % (13/33)/18 % (6/33)/59 % (36/61), p < 0.001. Relevant variables due to logistic regression analysis were high experience and the lesion types stenosis and combined stenosis+occlusion with odds ratios 2.300 (p = 0.012), 12.053 (p < 0.001), 3.189 (p = 0.003). Conclusion: Unrestricted implementation of immediate interventions in acute dysfunctional hemodialysis fistulas requires permanent availability of experienced interventionalists. The lesion types fibrosclerotic occlusion and thrombotic occlusion offer poor success rates for interventional revision.
    RöFo - Fortschritte auf dem Gebiet der R 12/2012; 185(3). DOI:10.1055/s-0032-1330274 · 2.76 Impact Factor
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    ABSTRACT: Hamartomas can occur in different areas of the breast, but they are rarely found in the breast. Myoid hamartomas with smooth muscle cells of the type described here are particularly unusual. The pathogenesis of this benign entity with its tendency to growth and recurrence is not clear. Excision is the therapy of choice. Capillary hemangiomas are rare vascular malformations of the breast which, in contrast to cavernous hemangiomas, usually remain clinically occult. It is important to differentiate these benign findings from malignant angiosarcoma. The possible heterogeneities between myoid hamartoma and capillary hemangioma using current breast imaging methods for the differential diagnosis (high-resolution ultrasound, duplex sonography, shear wave elastography, digital mammography, minimally invasive intervention) are discussed together with an overview of the literature.
    Geburtshilfe und Frauenheilkunde 05/2012; 72(5):412-418. DOI:10.1055/s-0031-1298571 · 0.85 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 05/2012; 184(S 01). DOI:10.1055/s-0032-1311303 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 05/2012; 184(S 01). DOI:10.1055/s-0032-1311304 · 1.96 Impact Factor
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    ABSTRACT: To evaluate prospectively the correlation of scar-formations after vacuum-assisted biopsy with different systems and needle-sizes and interventional bleeding/post-interventional hematoma. Between 01/2008 and 12/2009, 479 patients underwent vacuum-assisted biopsy under stereotactic-guidance, using the Mammotome(®)-system with 11/8-gauge and ATEC(®)-system with 12/9-gauge, whereas in 178 cases with representative benign histology no surgical-biopsy after vacuum-assisted biopsy was performed and at least a 2-plane-follow-up-mammogram after 6 month post-vacuum-assisted biopsy was available. Bleeding during intervention, hematoma post-intervention and scar-tissue was scored as minimal and moderate/severe. Statistical analysis included Chi-Square-trend-test, p-value <0.05 was considered to be significant. Significantly more bleedings and post-interventional hematomas for 8-gauge-Mammotome(®)-system vs. 11-gauge-Mammotome(®)-system (41.9% vs. 8.4%, p<0.001/35.5% vs. 16.7%, p=0.029), no significant-differences for the ATEC(®)-systems 9-gauge vs. 12-gauge (26.9% vs. 29.7%, p=0.799/42.3% vs. 43.2%, p=0.596). 11-gauge-Mammotome(®)-system vs. ATEC(®)-12-gauge-system revealed significantly less bleedings/hematomas (8.4% vs. 29.7%, p=0.015/16.7% vs. 43.2%, p=0.001), no significant differences for the large-systems (p=0.135/p=0.352). Follow-up of Mammotome(®)-11/8-gauge-system system has shown 13.1/16.1% minimal scar-formation and 1.2/3.2% moderate/severe scars, whereas ATEC(®)-12/9-gauge-system has shown 10.8/3.8% minimal scar-formation and 0/11.5% moderate/severe scars, no significant differences. No significant difference was found when comparing Mammotome(®)-11/8-g-systems vs. ATEC(®)-12/9-g-systems (p=0.609/p=0.823). There was also no correlation between risk of scar-formation after occurrence of bleeding or hematoma with any examined VAB-system or any needle size in this study (p=0.800). Using larger needle-sizes significantly (Mammotome(®))/not significant for ATEC(®)) more interventional bleedings and post-interventional hematomas were detected, only a tendency concerning scar-formation.
    European journal of radiology 02/2012; 81(5):e739-45. DOI:10.1016/j.ejrad.2012.01.033 · 2.65 Impact Factor
  • F K Schaefer, M Fürst, P J Schaefer
    RöFo - Fortschritte auf dem Gebiet der R 01/2012; 184(1):59-60. DOI:10.1055/s-0031-1281761 · 2.76 Impact Factor
  • B Fink, P Schäfer, L Frommelt
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    ABSTRACT: Preoperative diagnosis of periprosthetic infections is particularly important before revision of knee and hip arthroplasties because of the therapeutic consequences. Therefore, periprosthetic infections should be ruled out before any revision surgery is performed. Of the different diagnostic methods direct techniques which allow the direct detection of microorganisms with testing of antibiotic sensitivity are recommended. This allows microorganism-specific systemic and local antibiotic therapies and helps to reduce the risk of development of resistance. In our studies it could be shown that the time for incubation to detect microorganisms should be 14 days and that biopsy of periprosthetic tissues is superior to aspiration alone because it combines several diagnostic methods (microbiological and histological). It is preferable to repeating an aspiration when data are unclear, i.e. in cases of potentially false positives or negatives results of aspiration.
    Der Orthopäde 01/2012; 41(1):15-9. DOI:10.1007/s00132-011-1836-0 · 0.51 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2011; 183(S 01). DOI:10.1055/s-0031-1279580 · 1.96 Impact Factor
  • Journal of Vascular and Interventional Radiology 03/2011; 22(3). DOI:10.1016/j.jvir.2011.01.033 · 2.15 Impact Factor
  • Journal of Vascular and Interventional Radiology 03/2011; 22(3). DOI:10.1016/j.jvir.2011.01.240 · 2.15 Impact Factor
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    ABSTRACT: To examine and compare in an ex vivo study different nitinol stent designs intended for the superficial femoral artery (SFA) with regard to the appearance of fracture. Seven different 8-×40-mm nitinol stents were evaluated (Misago, Absolute, Smart, Luminexx, Sentinol, Lifestent NT, and Sinus-Superflex). Finite element analysis (FEA) was used for digitalized stent design comparison; the strain during stent movement was calculated for bending, compression, and torsion. Additional mechanical fatigue tests for bending (70°), compression (40%), and torsion (twisted counterclockwise by 180°) were performed up to 650,000 cycles or until a fracture was observed. The FEA bending test showed that only the Misago, LifeStent, and Absolute stents presented no zones of high strain; in the torsion test, the Smart stent also had no zones of high strain. Macroscopic evaluation after mechanical bending indicated that the LifeStent performed the best (no stent fracture after 650,000 cycles). Misago and Absolute stents showed fractures at 536,000 cycles and 456,667 cycles, respectively (range 320,000-650,000 cycles). After compression and torsion testing, Misago showed no stent fracture after 650,000 cycles. The worst performing stent was Luminexx during all test cycles. The 7 SFA stents showed differences in the incidence of high strain zones, which indicates a potential for stent fracture, as demonstrated by the mechanical fatigue tests. Differences in stent design might play a major role in the appearance of stent strut fracture related to restenosis and reocclusion.
    Journal of Endovascular Therapy 12/2010; 17(6):767-76. DOI:10.1583/10-3069.1 · 3.59 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 03/2010; 182. DOI:10.1055/s-0030-1252794 · 1.96 Impact Factor
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    ABSTRACT: To evaluate safety and efficacy of cryoplasty versus conventional angioplasty for focal popliteal arterial occlusive disease. Patients with focal atherosclerotic stenoses and occlusions of the popliteal artery were randomized to cryoplasty or conventional angioplasty as the initial treatment strategy. The primary objective was target lesion patency. The secondary endpoint was treatment success without the need for stents. Duplex ultrasonography was performed at 3, 6, 9, and 15 months. Eighty-six patients (mean age, 72 years; age range, 50-94 years) were enrolled in this study. Forty patients were randomized to cryoplasty and 46 to conventional angioplasty. Demographics, risk factors, clinical stage of disease, and lesion details were comparable. On intention-to-treat basis, initial success was 35% for cryoplasty versus 54% for conventional angioplasty (P = .02). The rate of grade C dissection was 35% after cryoplasty and 26% after conventional angioplasty (P = .4). Optional long-term percutaneous transluminal angioplasty (PTA) was performed in 58% of cryoplasty patients. The rate of stent placement for dissection and/or residual stenosis was 30% after cryoplasty (including long-term dilation) and 39% after conventional angioplasty (P = .34). The mean (+/-standard deviation) target lesion patency at 9 months was 79.3% +/- 7.5 for cryoplasty and 66.7% +/-8.1 for conventional angioplasty; however, the results are not significant (P = .14). Cryoplasty of the popliteal artery alone showed a lower anatomic success when compared with conventional angioplasty. Combined with optional long-term PTA, however, stent placement was not needed more often. There was a trend toward higher patency after cryoplasty, but differences were not statistically significant and results of long-term follow-up have to be awaited.
    Journal of vascular and interventional radiology: JVIR 02/2010; 21(2):186-94. DOI:10.1016/j.jvir.2009.10.021 · 1.81 Impact Factor
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    ABSTRACT: The purpose was to evaluate ex-vivo a prototype of a novel biopsy canula under CT fluoroscopy-guidance in ventilated porcine lung explants in respiratory motion simulations. Using an established chest phantom for porcine lung explants, n = 24 artificial lesions consisting of a fat-wax-Lipiodol mixture (approx. 70HU) were placed adjacent to sensible structures such as aorta, pericardium, diaphragm, bronchus and pulmonary artery. A piston pump connected to a reservoir beneath a flexible silicone reconstruction of a diaphragm simulated respiratory motion by rhythmic inflation and deflation of 1.5 L water. As biopsy device an 18-gauge prototype biopsy canula with a lancet-like, helically bended cutting edge was used. The artificial lesions were punctured under CT fluoroscopy-guidance (SOMATOM Sensation 64, Siemens, Erlangen, Germany; 30mAs/120 kV/5 mm slice thickness) implementing a dedicated protocol for CT fluoroscopy-guided lung biopsy. The mean-diameter of the artificial lesions was 8.3 +/- 2.6 mm, and the mean-distance of the phantom wall to the lesions was 54.1 +/- 13.5 mm. The mean-displacement of the lesions by respiratory motion was 14.1 +/- 4.0 mm. The mean-duration of CT fluoroscopy was 9.6 +/- 5.1 s. On a 4-point scale (1 = central; 2 = peripheral; 3 = marginal; 4 = off target), the mean-targeted precision was 1.9 +/- 0.9. No misplacement of the biopsy canula affecting adjacent structures could be detected. The novel steerable biopsy canula proved to be efficient in the ex-vivo set-up. The chest phantom enabling respiratory motion and the steerable biopsy canula offer a feasible ex-vivo system for evaluating and training CT fluoroscopy-guided lung biopsy adapted to respiratory motion.
    CardioVascular and Interventional Radiology 12/2009; 33(4):828-34. DOI:10.1007/s00270-009-9771-8 · 2.09 Impact Factor
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    ABSTRACT: We present a safe and quick technique for crossover embolization procedures of the internal iliac artery with high-profile guiding catheter systems, after a pull-through maneuver with establishment of a crossover catheter-snare system. The attached snare is used to stabilize and direct the guiding catheter.
    CardioVascular and Interventional Radiology 11/2009; 33(3):583-5. DOI:10.1007/s00270-009-9753-x · 2.09 Impact Factor
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    ABSTRACT: To develop different prototypes of permanently controllable rotating biopsy devices with determination of the most efficient prototype in biopsies in bovine myocardium. Five different prototypes of 18-gauge rotating biopsy devices were designed and constructed, four (1 - 4) with various drill-like cutting edges and one (5) cannula type with a lancet-like helically bent cutting edge. Using bovine myocardium as the biopsy tissue, n = 100 specimens per prototype were obtained, and a quantitative analysis including tissue fragmentation, length in mm and weight in mg was carried out. For statistical analysis, the chi-square test for tissue fragmentation and Kruskal-Wallis test for the parameters length and weight were calculated. Prototype 5 showed the highest rate of extraction of one-fragment specimens in n = 66 cases and the lowest rate of failure to obtain tissue in n = 11 cases. The mean length/weight were 4.15 mm/ 3.91 mg for prototype 1, 1.80 mm/ 1.66 mg for prototype 2, 4.61 mm/ 3.28 mg for prototype 3, 5.20 mm/ 3.74 mg for prototype 4, and 9.57 mm/ 6.97 mg for prototype 5. In all three categories, prototype 5 was significantly superior to the prototypes 1 - 4 with p < 0.001. The cannula type with a lancet-like helically bent cutting edge proved to be the most efficient prototype and may now be tested competitively against established automated biopsy devices in vitro.
    RöFo - Fortschritte auf dem Gebiet der R 10/2009; 181(12):1175-9. DOI:10.1055/s-0028-1109722 · 2.76 Impact Factor

Publication Stats

454 Citations
176.14 Total Impact Points


  • 2006–2014
    • University Medical Center Schleswig-Holstein
      • Department of Pediatrics
      Kiel, Schleswig-Holstein, Germany
  • 2006–2008
    • Christian-Albrechts-Universität zu Kiel
      • UKSH Klinik für Diagnostische Radiologie
      Kiel, Schleswig-Holstein, Germany
  • 2007
    • University Hospital of Heraklion
      Irákleio, Attica, Greece
  • 2006–2007
    • Universitätsklinikum Schleswig - Holstein
      • Klinik für Diagnostische Radiologie (Kiel)
      Kiel, Schleswig-Holstein, Germany