Introduction Lung ventilation is a standard sign of life in newborns. Post-mortem computed tomography (PMCT) is highly sensitive to the presence of gas in the body including the lungs. Current standard examinations to determine the pulmonary ventilation status in newborns are the flotation test and histology. The purpose of this study was to compare the accuracy of PMCT with the flotation test for determining the lung ventilation status with histological control as reference standard. A cut-off value as CT number in Hounsfield Units (HU) determining lung ventilation of newborns in PMCT should be established. Methods A total of 38 infant lungs were examined of which 21 lungs were from infants deceased shortly after live birth (control group) and 17 lungs belonged to infants where live birth was in question (study group). All lungs were examined using PMCT, flotation test, and histological examination. Results The control group showed an overall mean attenuation ± standard deviation of −219 HU ± 135; the study group of 45 ± 15 HU in histologically nonventilated lungs versus −192 ± 207 HU; ( p < 0.001) in ventilated lungs. The best cut-off value for optimal discrimination of ventilated and nonventilated lungs in newborns was −35 mean HU. Conclusion PMCT is equally well suited to determine lung ventilation as the flotation test. It provides additional information regarding pulmonary infiltration, degree of putrefaction, or signs of trauma (fractures, pneumothorax). Histology remains mandatory in ambiguous cases.

Purpose To objectify effects of an anatomical viewing scheme on the respective correctness of (a) findings, (b) interpretations, and (c) self-assessments of readers in chest radiographs acquired in one plane and the assessment of other influencing factors. Materials and methods In all, 20 radiologists with 3-60 months of full-time radiography experience evaluated 12 chest radiographs of varying difficulty: once with and once without using an anatomical viewing scheme with at least 1 month in between (n & x202f;= 480). In consensus of 3 radiological experts (a) and (b) were determined by means of a current computed tomography. The self-assessment (c) of readers was queried. Results (a) Findings were either missed or not described in 21%. Another 20% were recognized, but incorrectly described, (b) 62% of interpretations and 31% of derived clinical consequences were wrong and (c) in 39% of items the readers overestimated themselves. Experts were faster and better than novices, but for the scheme usage no further significant differences were detected (p & x202f;> 0.5, respectively). The most pronounced effect was found in comparison with the routine report produced by the joint evaluation of novices and experts being clearly superior even to the expert study results (a), (b) and (c) alone (p & x202f;< 0.001, respectively). Conclusion Reporting of chest X-rays acquired in one plane was often incomplete or even wrong, and the evaluators overestimated themselves, which was not influenced by the use of the anatomical viewing scheme. Since errors between the evaluators sometimes differed greatly, duplicate evaluation of the radiographs by two different radiologists, which is already the case in many training facilities, may possibly be advisable in general.

We are grateful for the important remarks by Dr Bouchut and colleagues. The letter highlights a highly relevant and interesting aspect of the topic. The saying "children are not small adults" is familiar to all of us. Accordingly, a well-functioning procedure for adult patients is not always applicable unchanged for children. Our study shows that the current procedure for establishing an intraosseous access in infants and children should also be critically reviewed. In infants and children in particular, peripheral venous access is sometimes difficult to establish. Therefore, an easy to use and well-functioning procedure is necessary. As described in the letter, the anatomical proportions of infants and children can deviate drastically from the proportions in adults and of course have a larger relative range. A study that reliably determines quantitative values for anatomical proportions is therefore certainly useful and of great importance. Depending on the results, procedures can then be altered accordingly and/or new devices can be developed that are tailored to the specific need. In our opinion, a corresponding study should answer two questions in particular:-Where is the potentially largest "landing area" for the needle, sorted by age group?-Of the various systems, are individual systems better or worse suited for the corresponding access due to their design? However, there are a few things to consider:-The proximal tibia is currently usually recommended as the standard site for intraosseous access,1Tobias J.D. Ross A.K. Intraosseous infusions: a review for the anesthesiologist with a focus on pediatric use.Anesth Analg. 2010; 110: 391-401Crossref PubMed Scopus (94) Google Scholar as the literature to date has described mostly poorer results in alternative sites.2Szarpak L. Truszewski Z. Smereka J. et al.A randomized cadaver study comparing first-attempt success between tibial and humeral intraosseous insertions using NIO device by paramedics: a preliminary investigation.Medicine (Baltimore). 2016; 95: e3724Crossref PubMed Scopus (15) Google Scholar However, these studies have been conducted on adults and are therefore not necessarily representative for infants and children. Our study cannot clarify this either, since in almost all cases the proximal tibia was chosen as the access site (only two cases with a different access site; in both cases malpositions of the needle3Maxien D. Wirth S. Peschel O. et al.Intraosseous needles in pediatric cadavers: rate of malposition.Resuscitation. 2019; 145: 1-7Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar).-In our study, the malpositions in which the corticalis was perforated on both sides were the minority of malpositions (31% in infants and 11% in children3Maxien D. Wirth S. Peschel O. et al.Intraosseous needles in pediatric cadavers: rate of malposition.Resuscitation. 2019; 145: 1-7Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar). Thus, not only the width of the medullary cavity seems to be decisive for success. This should be taken into account when revising the procedure.-As already described in the letter, the changed risk profile of extravasations and other procedure related risks depending on the puncture site should not be ignored.1Tobias J.D. Ross A.K. Intraosseous infusions: a review for the anesthesiologist with a focus on pediatric use.Anesth Analg. 2010; 110: 391-401Crossref PubMed Scopus (94) Google Scholar However, depending on the severity and life-threatening nature of the underlying disease, a higher risk may be acceptable. Sincerely, The authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.

Aim of the study: Intraosseous vascular access is a commonly conducted procedure especially in pediatric resuscitation. Very high success rates for intraosseous (IO) devices are reported. Aim of the study was to describe the rates of malposition of intraosseous needles (ION) in pediatric cadavers via post-mortem computed tomography (PMCT). Methods: 212 consecutive pediatric cadavers underwent PMCT, of which 38 cadavers had visible ION and were included in the study. They were divided into two subgroups depending on their age (n = 22 infant cadavers (age <1 year) and n = 16 child cadavers (age >= 1 year)). Two independent readers evaluated the number and position of ION. Results: In 22 infant cadavers 34 ION were found. Malposition of at least one ION was visible in 14 subjects (64%), among which 7 cadavers (32%) even had no correctly placed ION, thus being without established vascular access. Overall, 16 of the 34 used ION devices (47%) were in malposition. 23 ION were found in 16 child cadavers. In 8 subjects (50%) at least one ION was malpositioned, among which 3 cadavers (19%) had no correctly placed ION, resulting in a complete absence of vascular access. Overall, 9 of the 23 ION devices (39%) were malpositioned. Conclusion: Our study showed relatively high malposition rates for ION devices in pediatric cadavers which was not to be assumed regarding the success rates of 80% and higher in previous literature. This should be clarified by further studies in living patients.

Purpose Based on evaluation and examination results of students, a necessity for improvement of so far purely instructorbased radiological teaching at the local institution was determined. Aim of our study was to use one out of eight seminars to exemplify adaptation of the teaching concept according to learning theory knowledge, to determine the resulting effects and to interpret them. Materials and methods The institutional review board approved the prospective study of the seminar conversion, which was performed after the end of the winter semester 2015/2016. Didactically, this included a course split into online preparation, attendance phase and online follow-up with integration of interactive scaffolding, practice-oriented clinical teaching according to Stanford, Peyton skills transfer and extensive feedback into the attendance phase. At the beginning and at the end of each course, each student filled in identical, standardized questionnaires (n = 256 before and after conversion) using a 5-point Likert scale (1: very good; to 5: deficient) and additionally answered two randomly chosen written examination questions from a content-adapted questionnaire pool of the last five years. For statistical evaluation, the Mann-Whitney U-Test was used for evaluation data and Fisher's Exact test for exam questions. Results Before/after conversion, the subjective total evaluation score of students was 3.22 (mean value) +/- 1.51 (standard deviation) /1.66 +/- 0.78 (p < 0.001) and the objective proportion of correctly answered examination questions in the respective cohort at the beginning of the seminar 37.7/ 53.9 % and at the end of the seminar 55.1/84.6 % (p < 0.001). Conclusion The conversion of the test seminar resulted in both a better evaluation of the teaching unit by the students (evaluation) and a considerably higher rate of correctly answered examination questions from past state examinations (learning success). This supports transferring the concept to comparable teaching units.

Our aim was to develop an aortic stent graft phantom to simulate endoleak treatment and to find a tantalum content (TC) of ethylene-vinyl-alcohol-copolymer that causes fewer computed tomography (CT) beam hardening artefacts, but still allows for fluoroscopic visualization.

Rationale and Objectives: Dose reduction may compromise patients because of a decrease of image quality. Therefore, the amount of dose savings in new dose-reduction techniques needs to be thoroughly assessed. To avoid repeated studies in one patient, chest computed tomography (CT) scans with different dose levels were performed in corpses comparing model-based iterative reconstruction (MBIR) as a tool to enhance image quality with current standard full-dose imaging.Materials and Methods: Twenty-five human cadavers were scanned (CT HD750) after contrast medium injection at different, decreasing dose levels D0-D5 and respectively reconstructed with MBIR. The data at full-dose level, DO, have been additionally reconstructed with standard adaptive statistical iterative reconstruction (ASIR), which represented the full-dose baseline reference (FDBR). Two radiologists independently compared image quality (10) in 3-mm multiplanar reformations for soft-tissue evaluation of D0-D5 to FDBR (-2, diagnostically inferior; -1, inferior; 0, equal; +1, superior; and +2, diagnostically superior). For statistical analysis, the intraclass correlation coefficient (ICC) and the Wilcoxon test were used.Results: Mean CT dose index values (mGy) were as follows: D0/FDBR = 10.1 +/- 1.7, D1 = 6.2 +/- 2.8, D2 = 5.7 +/- 2.7, D3 = 3.5 +/- 1.9, D4 = 1.8 +/- 1.0, and D5 = 0.9 +/- 0.5. Mean IQ ratings were as follows: D0 = +1.8 +/- 0.2, D1 = +1.5 +/- 0.3, D2 = +1.1 +/- 0.3, D3 = +0.7 +/- 0.5, D4 = +0.1 +/- 0.5, and D5 = -1.2 +/- 0.5. All values demonstrated a significant difference to baseline (P < .05), except mean IQ for D4 (P = .61). ICC was 0.91.Conclusions: Compared to ASIR, MBIR allowed for a significant dose reduction of 82% without impairment of IQ. This resulted in a calculated mean effective dose below 1 mSv.

PurposeTo evaluate the use of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) during free breathing for the detection of acute pulmonary embolism (PE).Materials and MethodsEighteen subjects underwent free-breathing DCE MRI at 1.5T, eight of whom were patients with acute PE, as confirmed by routine computed tomography pulmonary angiography (CTPA). The remaining 10 subjects were healthy volunteers with no history or signs of pulmonary disease. From all DCE MRI data, maps of relative signal enhancement were calculated and assessed for the presence or absence of perfusion defects in each lung by two readers. Interreader variability, sensitivity, and specificity of free-breathing DCE MRI for the detection of PE were calculated using CTPA as the gold standard.ResultsOf the 16 patient's lungs, 15 were affected by acute PE according to CTPA. In patients and volunteers, DCE MRI sensitivity was 93% and 87% for readers 1 and 2, with specificities of 95% and 90%, respectively. Interreader agreement was substantial, with =0.77 (95% confidence interval: 0.44-1.0).ConclusionFree-breathing DCE MRI may have potential use for the assessment of PE, and does not require patient cooperation in breath-holding J. Magn. Reson. Imaging 2016;43:887-893

MR imaging: We analyzed breathhold and free-breathing lung DCE-MRI data sets of 5 healthy male volunteers (acquisitions of 40 3D volumes with 128 × 128×36 matrix and a temporal resolution of 1.3 s/volume using a fast view-sharing gradient echo sequence, flip angle: 15°; contrast agent: 0.1 mmol/kg bodyweight gadobutrol) to determine typical signal intensities of lung tissue pixels, noise levels, signal amplitudes of breathinginduced density variations, respiratory frequencies, and to define a typical arterial input function (AIF).

ObjectivesThe purpose of this study was to investigate whether quantification of pulmonary perfusion from dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) yields more reproducible results with data acquired during free breathing than with data from conventional breath-hold measurements. Material and MethodsTen healthy male volunteers underwent 2 imaging sessions at a clinical 1.5-T MRI system, separated by a week ± 1 day. Each of these sessions comprised 2 DCE MRI acquisitions: one performed during breath-hold and one during free, shallow breathing; both acquisitions were separated by at least 20 minutes. For all DCE MRI measurements, a standard dose of gadobutrol was used. Breath-hold measurements lasted 53 seconds; free-breathing acquisitions were performed in a total acquisition time of 146 seconds.Lung tissue was segmented automatically to minimize user influence, and pulmonary plasma flow (PPF) and volume (PPV) were quantified on a per-pixel basis with a 1-compartment model. Free-breathing measurements were analyzed twice, (a) including data from the entire acquisition duration and (b) after truncation to the duration of the breath-hold measurements. For further statistical analysis, median values of the resulting parameter maps were determined. To assess intraindividual reproducibility, intraclass correlation coefficients and coefficients of variation between the first and second measurements were calculated for breath-hold, truncated, and full free-breathing measurements, respectively. Differences in the coefficients of variation were assessed with a nonparametric 2-sided paired Wilcoxon signed rank test. ResultsAll 40 measurements were completed successfully. Maps of PPF and PPV could be calculated from both measurement techniques; PPF and PPV in the breath-hold measurements were significantly lower (P < 0.001) than in truncated and full free-breathing measurements. Both evaluations of the free-breathing measurements yielded higher intraclass correlation coefficients and lower coefficients of variation between the first and second measurements than the breath-hold measurements. ConclusionsBesides offering substantially higher patient comfort, free-breathing DCE MRI acquisitions allow for pixelwise quantification of pulmonary perfusion and hence generation of parameter maps. Moreover, quantitative perfusion estimates derived from free-breathing DCE MRI measurements have better reproducibility than estimates from the conventionally used breath-hold measurements.

Purpose To compare in a prospective noninferiority study optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in popliteal and infrapopliteal vessels. Materials and Methods OCT and IVUS images of 112 popliteal and infrapopliteal arterial segments were prospectively obtained from 16 patients with peripheral arterial occlusive disease. Three observers evaluated the corresponding OCT and IVUS images for image quality, artifact frequency, discriminability of vessel wall layers, and plaque composition. Measurements of the lumen, vessel, and plaque areas were compared for both modalities. Results The intrareader and interreader reproducibility of plaque tissue discrimination (0.88 vs 0.75), overall image quality, and vessel wall layer discriminability were significantly higher for OCT (all P < .001). Artifact frequency was higher in OCT, constraining the imaging of the tibioperoneal trunk. The results of measurements of the lumen and vessel area were comparable for both modalities (correlation > 0.9, P < .001). Plaque area measurements differed (correlation 0.8, P < .01) because OCT underestimated it. The OCT procedure caused vessel spasms in two patients. Conclusions OCT imaging of infrapopliteal arteries is feasible and safe and provides high image quality. It enables an accurate assessment of vessel lumen, wall, and plaque. Compared with IVUS, OCT images provide excellent image quality and superior visualization of vessel wall layers and different plaque components. The penetration depth of OCT restricts its use to suitable vessel regions.

Case reportEndovascular treatment of acute limb ischemia caused by an intravascularly deployed bioabsorbable plug of a vascular closure deviceDaniel Maxien, Barbara Behrends, Karla M. Eberhardt, Tobias Saam, Sven F. Thieme, Maximilian F. Reiser, and Marcus TreitlDaniel Maxien Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany Search for more papers by this author, Barbara Behrends Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany Search for more papers by this author, Karla M. Eberhardt Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany Search for more papers by this author, Tobias Saam Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany Search for more papers by this author, Sven F. Thieme Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany Search for more papers by this author, Maximilian F. Reiser Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany Search for more papers by this author, and Marcus Treitl Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany Search for more papers by this authorPublished Online:March 13, 2013https://doi.org/10.1024/0301-1526/a000260PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInReddit SectionsMoreFiguresReferencesRelatedDetailsCited byEndovascular foreign body removal of a MynxGrip polyethylene glycol (PEG) sealant embolus using a cerebral stent retriever1 March 2021 | CVIR Endovascular, Vol. 4, No. 1Successful bailout procedure for acute popliteal artery occlusion associated with EXOSEAL® vascular closure device: a case report21 March 2019 | Journal of Medical Case Reports, Vol. 13, No. 1Large-scale experience with an anchorless vascular closure device in a real-life clinical setting8 October 2014 | Clinical Research in Cardiology, Vol. 104, No. 2A Novel Technique to Retrieve a Maldeployed Vascular Closure Device1 February 2015 | Journal of Endovascular Therapy, Vol. 22, No. 1 Volume 42Issue 2March 2013ISSN: 0301-1526eISSN: 1664-2872 InformationVasa (2013), 42, pp. 144-148 https://doi.org/10.1024/0301-1526/a000260.© 2013Hogrefe AGKeywordsVessel occlusionvascular closure deviceExoSealendovascular treatmentendovascular interventionacute limb ischemiaPDF download

To correlate a Dual Energy (DE)-based visual perfusion defect scoring system with established CT-based and clinical parameters of pulmonary embolism (PE) severity.

PURPOSE:To assess the clinical value of oxygen-enhanced magnetic resonance imaging (oeMRI) in patients with pulmonary hypertension (PH) by correlation with ventilation/perfusion (V/Q) scintigraphy.MATERIALS AND METHODS:In all, 33 patients with known PH underwent V/Q scintigraphy and oeMRI. oeMRI was used to assess the regional pulmonary function based on relative-signal-enhancement (RSE) and cross-correlation-coefficient (CCC) maps, evaluating mean RSE (mRSE), fraction of oxygen-activated pixels (fOAP), and mean CCC (mCCC). Two reviewers, blinded to the results of scintigraphy, performed visual detection of diseased lung areas.RESULTS:In 26 of the 33 patients (79%) the image quality of oeMRI reached a diagnostic level. In total, 150 lung areas were analyzed and compared. Sensitivities/specificities of oeMRI for detecting these defects were: RSE vs. ventilation scintigraphy 92%/73%; RSE vs. perfusion scintigraphy 60%/87%; CCC vs. ventilation scintigraphy 89%/81%; CCC vs. perfusion scintigraphy 50%/87%. The number of diseased lung areas in oeMRI correlated significantly with the number in V/Q scintigraphy (P < 0.01). mRSE showed a significant correlation with the number of diseased lung areas in ventilation scintigraphy (P < 0.05).CONCLUSION:oeMRI is feasible in PH patients, yielding an overall moderate agreement between oeMRI and V/Q scans, with a good sensitivity of oeMRI for the detection of ventilation defects as compared with ventilation scintigraphy.

Purpose To evaluate the safety, comfort, and efficacy of an extravascularly deployed bioabsorbable plug–based vascular closure device (VCD) for sealing 6-F antegrade access sites in patients requiring peripheral endovascular intervention. Methods A single-center, single-arm, prospective study to evaluate the 6-F ExoSeal VCD in terms of technical success, adverse events, and patient comfort enrolled 59 unselected symptomatic patients (42 men; mean age 72.1±9.3 years) suffering from peripheral artery disease in an 11-month period. Patients with high body mass index (BMI) or calcification at the access site were not excluded. Calcifications of the access vessel were scored as grades 1–4 from fluoroscopic images. The pain level during implantation was evaluated after the procedure using a visual rating scale. Results Technical success rate was 98.3%; 1 primary device failure was converted to manual compression. In addition, 1 (1.7%) pseudoaneurysm, 2 (3.4%) minor hematomas, and 1 (1.7%) minor secondary bleeding were observed. There was no intravascular application of the device detected. Neither BMI, calcification of the access vessel (present in 74.6%, mean score 1.4±1.1), age, nor blood clotting had any statistically significant influence on adverse events. In total, 55 (93.2%) patients felt no pain during the VCD implantation. Conclusion The tested VCD was safe, with an excellent technical success rate even in cases with severe access vessel calcification.

Poster: ECR 2011 / C-1690 / Dose saving potential of adaptive statistical iterative reconstruction (ASIR) in 64-row CT imaging of the chest by: S. Wirth , L. Michael, M. Scherr, M. Korner, U. Linsenmaier, E. Ziegeler, F. Muck, D. Maxien, M. F. Reiser; Munich/DE

Objective To evaluate the feasibility of dual-energy CT (DECT) ventilation imaging in combination with DE perfusion mapping for a comprehensive assessment of ventilation, perfusion, morphology and structure of the pulmonary parenchyma. Methods Two dual-energy CT acquisitions for xenon-enhanced ventilation and iodine-enhanced perfusion mapping were performed in patients under artificial respiration. Parenchymal xenon and iodine distribution were mapped and correlated with structural or vascular abnormalities. Results In all datasets, image quality was sufficient for a comprehensive image reading of the pulmonary CTA images, lung window images and pulmonary functional parameter maps and led to expedient results in each patient. Conclusion With dual-source CT systems, DECT of the lung with iodine or xenon administration is technically feasible and makes it possible to depict the regional iodine or xenon distribution representing the local perfusion and ventilation.

Poster: ECR 2010 / C-0933 / Value of oxygen-enhanced MRI (oeMRI) in patients with pulmonary arterial hypertension (PAH) by: D. Maxien , O. Dietrich, S. Thieme, J. Behr, M. F. Reiser, K. Nikolaou; Munich/DE

OBJECTIVES:Oxygen-enhanced MRI (O2-MRI) is frequently based on a block paradigm consisting of a series of consecutive T1-weighted scans acquired during alternating blocks with inhalation of room air and of pure oxygen. This design results in a complex signal-time course for each pixel, which displays the oxygen wash-in and wash-out processes and provides spatially resolved information about the lung function. The purpose of the present study was to optimize the signal-time-course analysis to extract (pixelwise) the maximum amount of information from the acquired data, and to introduce an appropriate cross-correlation approach for data sets containing the oxygen wash-in and wash-out periods.MATERIALS AND METHODS:O2-MRI data of 11 healthy volunteers were acquired with a multislice inversion-recovery single-shot turbo-spin-echo sequence at 1.5 Tesla; lung and spleen were manually segmented on all 44 acquired slices. Six different model functions were pixelwise fitted to the data and compared using the Akaike information criterion. Four different reference functions were compared for cross-correlation analysis.RESULTS:The optimal model function is a piecewise exponential function (median enhancement in lung/spleen: 16.3%/14.8%) with different time constants for wash-in (29.4 seconds/72.7 seconds) and wash-out (25.1 seconds/29.6 seconds). As a new parameter, it contains the delay between switching the gas supply and the onset of the signal change (4.8 seconds/24.5 seconds). Optimal cross-correlation results were obtained with a piecewise exponential reference function, which was temporally shifted to maximize the correlation, yielding median correlation coefficients of 0.694 and 0.878, median time delays of 7.5 seconds and 38.6 seconds, and median fractions of oxygen-activated pixels of 83.6% and 92.2% in the lung and the spleen, respectively.CONCLUSIONS:It was demonstrated that the pixelwise assessment of O2-MRI data are optimally performed with piecewise exponential functions. Cross-correlation analysis with a piecewise exponential reference function results in significantly higher fractions of oxygen-activated pixels than with rectangular functions.

Poster: "ECR 2013 / C-0276 / CT beam hardening artifacts caused by the ethylene vinyl alcohol copolymer Onyx after treatment of endoleaks: experimental optimisation of radiopacification by reduction of the tantalum content in an aortic stent graft phantom with endoleaks" by: "K. M. Eberhardt, D. Maxien, M. F. Reiser, M. Treitl; Munich/DE"