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Objectives: To evaluate the performance and efficacy of endovascular irradiation after percutaneous transluminal angioplasty (PTA) of de-novo femoropopliteal stenoses in a pilot study., Methods: 6 patients received non-centered endovascular irradiation (12 Gray at surface of the vessel wall) immediately after angioplasty of de-novo femoropopliteal stenosis, 1 patient was given centered endovascular irradiation using 192-iridium (12 Gray at surface of the vessel wall) Centered irradiation was considered for two other patients. Duplex sonographies and interviews were performed the day before and after PTA and after 1, 3, 6, 9, 12, 18, 24 months up to 4 years. Intraarterial angiography was performed in symptomatic patients., Results: Non-centered endovascular irradiation was possible in all patients without problems or complications. Centered irradiation was not possible in two patients with the cross-over approach. One thromboembolic complication occurred during centered irradiation. Both restenosis and new stenosis at the edge of irradiated distance occurred in 1/7 patients. No other side effects were observed during follow-up., Conclusions: In our pilot study endovascular irradiation after angioplasty of de-novo femoropopliteal stenosis was possible with low rates of complications and restenosis and taking vessel anatomy into account.

Purpose: To estimate the accuracy of the determination of tip position of MR compatible biopsy needles based on signal voids and artifacts in MR guided biopsies., Method: In a nylon grid phantom an MR compatible 18G needle (E-Z-EM) was measured in a 1.0 T imager using TSE- and FFE-sequences of 20 s and 40 s duration in 34 different orientations of needle versus B0, frequency and slice selection gradient. 4 radiologists with no experience in the evaluation of signal void artifacts estimated the needle tip positions from needle tip artifacts. The readers determined the needle tip before and after a 15 minute training session based on high resolution images with explanation of size and shape of specific artifacts of biopsy needles in 12 different orthogonal or parallel orientations to B0 and frequency encoding gradient that are possible if the needle lies parallel to the slice, i.e. orthogonal to the slice selection gradient. The values obtained before and after the training session were compared to the real position of the needle tip., Results: Mean distance of actual needle tip and tip position as determined from images was 1.8 +/- 2.3 mm in TSE-versus 2.5 +/- 1.2 mm in FFE-images, with the needle length overestimated. After a 15 minute training session the positioning error decreased significantly to 0.2 +/- 1.8 mm for TSE-sequences and to 1.0 +/- 1.8 mm for FFE-sequences. A higher accuracy of tip localization was obtained with TSE sequences., Conclusion: In MR guided biopsies using FFE- and TSE-sequences the needle position can be more accurately determined if the reader is familiar with the 12 orthogonal or parallel positions of the needle with respect to B0 and frequency encoding gradient and the corresponding artifacts.

Purpose: Who refers patients for a color duplex ultrasonography (CDUS) in the routine work of a radiological university department and how frequent are repeat examinations?, Material and Methods: 1110 patients had at least one CDUS examination between 5/97 and 5/98. The specialities of the referring physicians/primary examiners and the inpatient or outpatient status of the patients were documented at the first consultation. Additionally the patients were asked by the medical staff, whether, how often, and by whom ultrasonographic, CT, or MR examinations of the same organ system had been carried out during the last 4 weeks without evidence of any clinical changes., Results: 97% of the 1118 patients were referred by one of the university departments. The arterial system was exclusively investigated in 58% and the venous system in 29% of the cases. 81% of the 651 arterial examinations were requested by the Departments of Vascular/Cardiac Surgery and Radiology. 75 repeated ultrasonographic examinations were documented in 67 (6%) of the 1118 consultations. Repetitions were documented in 8% of the arterial and in 3% of the venous examinations. X-ray angiographies were already done or planned in 105 of the 625 arterial CDUS (16%). Ultrasonographic referrals with parallel phlebographies (1% of 320 venous indications) as well as parallel CT and MR examinations (1% of the 1118 consultations, respectively) were the exception., Conclusions: In the described setting, CDUS was mainly used to assess the arterial vascular system prior to vascular surgery and radiological interventions. Repeat ultrasonographies alone (6%) and parallel examinations altogether (14%) were observed less frequently than expected.

Purpose: What is the percentage of repeat examinations in the ultrasonographic section of a radiological university department?, Methods: All 4116 patients, who were first examined in the sonographic section of the Radiologic Department of the University of Cologne from 5/97 to 5/98, were asked by the medical staff, whether, how often and by whom ultrasonographic, CT or MR examinations of the same organ system had been carried out during the last 4 weeks without evidence of clinical changes. The data were documented using a structured questionnaire., Results: Sonographic repeated examinations documented in 443 (10.8%) of the 4116 consultations. The proportion of in- to outpatients with repeat examinations was 26.0% to 74.0%. Contrarily, the repeated ultrasonographies were done by practitioners in 62.3% and by the university staff in 33.2% (radiology 48.2%). With regard to the 4116 consultations, the abdomen (81.1%) was the organ system most often examined repeatedly. Computed tomographies were already done or planned in 305 of 4116 patients (7.4%) and MR-tomographies were already done or planned in 57 patients (1.4%)., Conclusion: The rate of repeated ultrasonographic examinations in a radiological university hospital was 19.6%.