T A Bley

University of Wuerzburg, Würzburg, Bavaria, Germany

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Publications (185)444.44 Total impact

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    ABSTRACT: To assess whether ECG-gated non-contrast 2D steady-state free precession (SSFP) imaging allows for exact monitoring of aortic diameters in Marfan syndrome (MFS) patients using non-ECG-gated contrast-enhanced 3D magnetic resonance angiography (CE-MRA) and echocardiography for intraindividual comparison.
    European radiology. 10/2014;
  • DGMP 2014, Zurich; 09/2014
  • Der Radiologe 09/2014; · 0.47 Impact Factor
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    ABSTRACT: Purpose To assess the diagnostic accuracy of contrast material-enhanced magnetic resonance (MR) imaging of superficial cranial arteries in the initial diagnosis of giant cell arteritis (GCA). Materials and Methods Following institutional review board approval and informed consent, 185 patients suspected of having GCA were included in a prospective three-university medical center trial. GCA was diagnosed or excluded clinically in all patients (reference standard [final clinical diagnosis]). In 53.0% of patients (98 of 185), temporal artery biopsy (TAB) was performed (diagnostic standard [TAB]). Two observers independently evaluated contrast-enhanced T1-weighted MR images of superficial cranial arteries by using a four-point scale. Diagnostic accuracy, involvement pattern, and systemic corticosteroid (sCS) therapy effects were assessed in comparison with the reference standard (total study cohort) and separately in comparison with the diagnostic standard TAB (TAB subcohort). Statistical analysis included diagnostic accuracy parameters, interobserver agreement, and receiver operating characteristic analysis. Results Sensitivity of MR imaging was 78.4% and specificity was 90.4% for the total study cohort, and sensitivity was 88.7% and specificity was 75.0% for the TAB subcohort (first observer). Diagnostic accuracy was comparable for both observers, with good interobserver agreement (TAB subcohort, κ = 0.718; total study cohort, κ = 0.676). MR imaging scores were significantly higher in patients with GCA-positive results than in patients with GCA-negative results (TAB subcohort and total study cohort, P < .001). Diagnostic accuracy of MR imaging was high in patients without and with sCS therapy for 5 days or fewer (area under the curve, ≥0.9) and was decreased in patients receiving sCS therapy for 6-14 days. In 56.5% of patients with TAB-positive results (35 of 62), MR imaging displayed symmetrical and simultaneous inflammation of arterial segments. Conclusion MR imaging of superficial cranial arteries is accurate in the initial diagnosis of GCA. Sensitivity probably decreases after more than 5 days of sCS therapy; thus, imaging should not be delayed. Clinical trial registration no. DRKS00000594 © RSNA, 2014.
    Radiology 08/2014; · 6.34 Impact Factor
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    ABSTRACT: Objectives To evaluate in-stent lumen visibility of 27 modern and commonly used coronary stents (16 individual stent types, two stents at six different sizes each) utilising a third-generation dual-source CT system. Methods Stents were implanted in a plastic tube filled with contrast. Examinations were performed parallel to the system's z-axis for all stents (i.e. 0°) and in an orientation of 90° for stents with a diameter of 3.0 mm. Two stents were evaluated in different diameters (2.25 to 4.0 mm). Examinations were acquired with a collimation of 96 × 0.6 mm, tube voltage of 120 kVp with 340 mAs tube current. Evaluation was performed using a medium-soft (Bv40), a medium-sharp (Bv49) and a sharp (Bv59) convolution kernel optimised for vascular imaging. Results Mean visible stent lumen of stents with 3.0 mm diameter ranged from 53.3 % (IQR 48.9−56.7 %) to 73.9 % (66.7−76.7 %), depending on the kernel used at 0°, and was highest at an orientation of 90° with 80.0 % (75.6−82.8 %) using the Bv59 kernel, strength 4. Visible stent lumen declined with decreasing stent size. Conclusions Use of third-generation dual-source CT enables stent lumen visibility of up to 80 % in metal stents and 100 % in bioresorbable stents.
    European Radiology 07/2014; · 4.34 Impact Factor
  • VASA. Zeitschrift für Gefässkrankheiten. 07/2014; 43(4):298-302.
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    ABSTRACT: To include the flip angle distribution caused by the slice profile into the model used for describing the relaxation curves observed in inversion recovery Look-Locker FLASH T1 mapping for a more accurate determination of the relaxation parameters.
    Magnetic resonance imaging. 06/2014;
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    ABSTRACT: To assess deep temporal artery and temporalis muscle involvement in patients with giant cell arteritis (GCA).
    European Radiology 06/2014; · 4.34 Impact Factor
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    ABSTRACT: Obtaining functional information on the human lung is of tremendous interest in the characterization of lung defects and pathologies. However, pulmonary ventilation and perfusion maps usually require contrast agents and the application of electrocardiogram (ECG) triggering and breath holds to generate datasets free of motion artifacts. This work demonstrates the possibility of obtaining highly resolved perfusion-weighted and ventilation-weighted images of the human lung using proton MRI and the SElf-gated Non-Contrast-Enhanced FUnctional Lung imaging (SENCEFUL) technique. The SENCEFUL technique utilizes a two-dimensional fast low-angle shot (FLASH) sequence with quasi-random sampling of phase-encoding (PE) steps for data acquisition. After every readout, a short additional acquisition of the non-phase-encoded direct current (DC) signal necessary for self-gating was added. By sorting the quasi-randomly acquired data according to respiratory and cardiac phase derived from the DC signal, datasets of representative respiratory and cardiac cycles could be accurately reconstructed. By application of the Fourier transform along the temporal dimension, functional maps (perfusion and ventilation) were obtained. These maps were compared with dynamic contrast-enhanced (DCE, perfusion) as well as standard Fourier decomposition (FD, ventilation) reference datasets. All datasets were additionally scored by two experienced radiologists to quantify image quality. In addition, one initial patient examination using SENCEFUL was performed. Functional images of healthy volunteers and a patient diagnosed with hypoplasia of the left pulmonary artery and left-sided pulmonary fibrosis were successfully obtained. Perfusion-weighted images corresponded well to DCE-MRI data; ventilation-weighted images offered a significantly better depiction of the lung periphery compared with standard FD. Furthermore, the SENCEFUL technique hints at a potential clinical relevance by successfully detecting a perfusion defect in the patient scan. It can be concluded that SENCEFUL enables highly resolved ventilation- and perfusion-weighted maps of the human lung to be obtained using proton MRI, and might be interesting for further clinical evaluation. Copyright © 2014 John Wiley & Sons, Ltd.
    NMR in Biomedicine 05/2014; · 3.45 Impact Factor
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    ABSTRACT: PurposeTo iteratively correct for deviations in radial trajectories with no need of additionally performed calibration scans.Theory and Methods Radially acquired data sets—even when undersampled to a certain extend—inherently feature an oversampled area in the center of k-space. Thus, for a perfectly measured trajectory and neglecting noise, information is consistent between multiple measurements gridded to the same Cartesian position within this region. In the case of erroneous coordinates, this accordance—and therefore a correction of the trajectory—can be enforced by an algorithm iteratively shifting the projections with respect to each other by applying the GRAPPA operator. The method was validated in numerical simulations, as well as in radial acquisitions of a phantom and in vivo images at 3T. The results of the correction were compared to a previously proposed correction method.ResultsThe newly introduced technique allowed for a reliable trajectory correction in each of the presented examples. The method was able to remove artifacts as effectively as methods that are based on data from additional calibration scans.Conclusion The iterative technique introduced in this paper allows for a correction of trajectory errors in radial imaging with no need for additional calibration data. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 05/2014; · 3.27 Impact Factor
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    ABSTRACT: PURPOSE In Fabry disease progressive deposition of sphingolipids in different organs has been reported. High-field 1H-MR-spectroscopy (MRS) allows non-invasive determination of myocardial lipid content. This study investigates the role of myocardial steatosis in the complex pathomechanism of Fabry cardiomyopathy. METHOD AND MATERIALS In 14 patients (9 female, 5 male; 39 ± 13 years [range 17-52 years]) with genetically proven Fabry disease, myocardial triglycerides were quantified by 1H MRS (respiratory motion compensated, ECG triggered) in vivo using a 3 T scanner (Magnetom TRIO, Siemens Sector HealthCare, Germany). Single-voxel-spectroscopy was performed with and without water suppression. The voxel was positioned in the interventricular septum using a four-chamber and short-axis orientation at end systole to avoid signal contamination by epicardial fat. Two triglyceride peaks were measured (methylene groups at 1.3 ppm, methyl groups at 0.9 ppm) relative to the resonance from tissue water at 4.7 ppm. The myocardial lipid content was expressed as triglycerides-to-water ratio (%). In addition left ventricular (LV) mass and ejection fraction (EF) were assessed by MRI. Nine healthy volunteers (4 female, 5 male) without a history of cardiac or metabolic disease served as control group. RESULTS In all patients 1H spectra were successfully acquired. In patients the mean triglyceride-to-water ratio was 1.7% (min. 0.1%; max. 6.2%). On average the control group showed a lower (p=0.05) triglyceride-to-water ratio of 0.49% (min. 0.1%; max. 1.9%). Compared to healthy controls, LV mass (mean ± standard deviation; 120 ± 36 g) tended to be higher in Fabry patients (FP) (142 ± 43.9 g) (p=0.1). Mean EF was similar in both groups (67 % in FP vs. 66 % in controls). CONCLUSION High-field 1H-MR-spectroscopy using 3T scanners allows non-invasive assessment of myocardial lipid content in FP. In a relatively small patient collective we observed an elevated myocardial triglyceride content. This finding warrants further studies with larger patient groups, especially concerning sub-group analysis of LE positive and negative FPs. CLINICAL RELEVANCE/APPLICATION Besides data regarding functional and morphological alterations MRS delivers new insights into myocardial lipid metabolism in FP. This might help to further optimize the therapy for this rare disease.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: PURPOSE/AIM To demonstrate the whole procedure of normal and pathologic defecation in conventional (CD) and MR defecography (MRD) as well as imaging findings after surgical treatment (e.g. STARR/POP STARR). CONTENT ORGANIZATION 1. To review the indications 2. To show the techniques including dynamic 3D MR defecography 3. To demonstrate important measures as anorectal angle (ARA) and perineal descent (PD); to get familiar with pathologic findings such as intussuception, enterocele, rectocele, sigmoidocele, cystocele, Retzius and Douglas hernia; to discriminate functional disorders (e.g. spastic pelvis floor syndrome) 4. To learn about surgical treatment options like i.e. stapled transanal resection (STARR) for intussusception and POP STARR for pelvic organ prolaps and their appearance in CD and MRD 5. Limitations of both modalities. SUMMARY The radiologist - especially when working in the coloproctologic field - should be familiar with the techniques, indications and limitations of CD and MRD. As there are successful surgical procedures in patients with obstructive defecation syndrome he should have experience in interpreting post-operative defecography.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: Purpose: Marfan syndrome (MFS) is a genetic disorder of the connective tissue. Aortic root dilation is a main criterion of the Ghent Nosology. Dural ectasia and the presence of mitral valve prolapse (MVP) contribute to its systemic score. The purpose of this study was to investigate the frequency of dural ectasia and its correlation with cardiovascular manifestations in a pediatric study population.Patients and methods: 119 pediatric patients with confirmed or suspected MFS were examined in the local Marfan Clinic. 31 children with MFS who underwent magnetic resonance imaging (MRI) were included. Each patient was evaluated according to the Ghent nosology. Echocardiography was used to measure the aortic root diameter and assess the presence of MVP and mitral regurgitation. Z-scores were calculated for the evaluation of the aortic root diameters. MRI was performed to determine the dural sac ratio (DSR).Results: The prevalence of dural ectasia was 90.3 %, of aortic root dilation 32.2 %, of MVP 64.5 % and of mitral regurgitation 51.6 %. DSR at L5 correlated with the intraindividual z-scores (slope, 3.62 ± 1.5 [0.56; 6.68]; r = 0.17; p = 0.02; F = 5.84). Z-scores ≥ 2 were accompanied by dural ectasia in 100 %, MVP in 95 % and mitral regurgitation in 100 % of cases. MVP was accompanied by mitral regurgitation in 70 % of cases.Conclusion: As the examined cardiac manifestations show a coincidence with dural ectasia in 95 - 100 % of cases, MRI for diagnostic dural sac imaging should be reserved for MFS suspicions with the absence of those manifestations in order to establish the diagnosis according to the Ghent criteria. Thus, the present study supports the recent downgrading of dural ectasia to a contributor to the systemic score.Citation Format:
    RöFo - Fortschritte auf dem Gebiet der R 09/2013; · 2.76 Impact Factor
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    ABSTRACT: To investigate the influence of respiration on field maps for geometric distortion correction derived from two rapidly acquired consecutive echo planar images. Displacement maps of the brains of seven healthy volunteers were acquired under breath hold and free breathing for a 64 × 64 pixel image matrix using phase labeling for additional coordinate encoding (PLACE). The maps were transformed into undistorted gradient echo space and analyzed with regard to standard deviation and absolute deviation from an accurate reference field map derived from a multiecho reference scan. Standard deviations between PLACE field maps and absolute difference from the reference field map are a factor of about 3 higher under free breathing than under breath hold. The mean deviation decreases from 3 pixels in the slice closest to the lung to 1 pixel in the most superior slice under free breathing and from 1 to <0.5 pixels under breath hold. Maps obtained under free breathing can significantly impact the field map and thus corrupt the geometric distortion correction. The effect can be greatly reduced by acquiring the field map data under breath hold. Data acquired under free breathing can be improved with retrospective phase correction or by averaging several field maps. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 09/2013; · 3.27 Impact Factor
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    ABSTRACT: BACKGROUND: There is growing concern over the long-term radiation exposure from serial computed tomographic (CT) scan follow-up after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs). Screening for endoleaks with non-contrast-enhanced volumetric CT has been shown to significantly reduce radiation doses. We evaluated the use of NCT as the primary method of follow-up after EVAR of AAAs. METHODS: Our institutional post-EVAR CT protocol consisted of contrast-enhanced CT angiography (CTA) 1 month after repair, followed by NCT at 3 or 6 and 12 months, and annually thereafter. At each follow-up scan, immediate 3-dimensional volume analysis was performed. If the volume change was <2%, NCT follow-up was continued. If the volume increased by ≥2% on nonenhanced images, contrast-enhanced CT was performed immediately to identify potential endoleaks. All images were reviewed by an experienced cardiovascular radiologist. End points included identification of endoleak, reintervention, and rupture. RESULTS: Over a 7-year period, 126 patients were followed. Serial CTA was performed in 59 patients, while 67 patients were followed with the NCT protocol. The mean follow-up was 2.07 years. There were no differences in age, sex, or initial aneurysm volume or size. There were 35 total endoleaks identified. Twenty of these were early endoleaks (<30 days post-EVAR). The remaining 15 leaks were late in nature (10 in the contrast group and 5 in the noncontrast group; P = 0.17). NCT aneurysm sac volume changes prompted contrasted studies in all 5 late leaks. The mean volume change was 11.2 cm(3), an average change of 5.88%. These findings were not significantly different than the late leaks found by routine contrast studies (8.9 cm(3); 4.98% [P = 0.58]). There were no delayed ruptures or emergent reinterventions in the NCT group. CONCLUSIONS: Serial NCT appears to be safe and effective as the sole means of follow-up after EVAR for AAAs. AAA volume increases of ≥2% should prompt further contrast-enhanced CT imaging. Changes of <2% can be safely followed with serial NCT. This protocol requires dedicated cardiovascular radiologist involvement, and patients should be retained in the radiology suite until real-time image evaluation can be completed.
    Annals of Vascular Surgery 05/2013; · 0.99 Impact Factor
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    ABSTRACT: OBJECTIVE: To evaluate the association between aortic arch calcifications (AAC) on chest radiography and coronary artery calcium (CAC) score determined by CT. METHODS: A total of 128 patients (75 men; 69.3 ± 14.7 years) who underwent chest radiography and CAC scoring at CT were included in this retrospective analysis. The extent of AAC on chest radiography was evaluated independently by two blinded observers using a semi-quantitative four-point scale (0-3). Intra- and interobserver agreement was assessed by weighted ĸ statistics. Amount of AAC determined on radiography was correlated with CAC and ROC analyses performed to characterise the diagnostic performance of AAC grading. RESULTS: Excellent intraobserver (ĸ = 0.82) and good interobserver (ĸ = 0.75) agreement of AAC grading was noted. Moderate agreement (ĸ = 0.46, 95 % CI 0.36-0.56) with a linear trend (P < 0.0001) between AAC grades and CAC scores was found. Cut-off between AAC grades 0-2 and 3 had a sensitivity of 38.6 %, specificity of 96.4 %, PPV of 85.0 %, NPV of 75.0 % and accuracy of 76.6 % for the correct identification of CAC scores greater than 400. CONCLUSION: Semi-quantitative AAC grading on chest radiography is reliable and positively associated with CAC scoring. We propose to report the extent of AAC in comprehensive radiological reports as "not present", "moderate" or "severe", as severe AAC strongly suggests coronary artery calcification. KEY POINTS: • Semi-quantitative aortic arch calcification (AAC) grading on plain chest radiography appears reliable. • AAC grading is positively associated with CT coronary artery calcium scoring. • AAC grading has a high specificity for ruling out CAC scores greater than 400. • We propose the reporting of the extent of AAC grade in chest X-ray (CXR) reports.
    European Radiology 05/2013; · 4.34 Impact Factor
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    ABSTRACT: Giant cell arteritis (GCA) is the most common systemic vasculitis in persons aged 50 and above (incidence, 3.5 per 100 000 per year). It affects cranial arteries, the aorta, and arteries elsewhere in the body, e.g., in the limbs. We selectively review the pertinent literature, including guidelines and recommendations from Germany and abroad. The typical symptoms of new-onset GCA are bitemporal headaches, jaw claudiacation, scalp tenderness, visual disturbances, systemic symptoms such as fever and weight loss, and polymyalgia. The diagnostic assessment comprises laboratory testing (erythrocyte sedimentation rate, C-reactive protein), imaging studies (duplex sonography, high-resolution magnetic resonance imaging, positron-emission tomography), and temporal artery biopsy. The standard treatment is with corticosteroids (adverse effects: diabetes mellitus, osteoporosis, cataract, arterial hypertension). A meta-analysis of three randomized controlled trials led to a recommendation for treatment with methotrexate to lower the recurrence rate and spare steroids. Patients for whom methotrexate is contraindicated or who cannot tolerate the drug can be treated with azathioprine instead. Giant cell arteritis, if untreated, progresses to involve the aorta and its collateral branches, leading to various complications. Late diagnosis and treatment can have serious consequences, including irreversible loss of visual function.
    Deutsches Ärzteblatt International 05/2013; 110(21):376-86. · 3.54 Impact Factor
  • P Bannas, G Adam, T A Bley
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    ABSTRACT: Many scientific manuscripts submitted for publication are flawed by conceptual mistakes. This leads to the rejection of potentially valuable scientific data in renowned journals. This article intends to guide young researchers with respect to writing a well-structured scientific radiological manuscript.
    RöFo - Fortschritte auf dem Gebiet der R 03/2013; · 2.76 Impact Factor
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    ABSTRACT: Purpose: In 2011 a nationwide outbreak of Shiga toxin-producing E. coli (STEC) O104:H4 infection occurred in Germany with severe hemorrhagic colitis and hemolytic-uremic syndrome (HUS). We defined abdominal radiologic findings in these patients and correlated them with clinical parameters. Materials and Methods: 23 patients (7 men; age: 48 ± 19 years) with O104:H4 colitis and/or HUS received abdominal CT (n = 12) or radiographs (n = 11). Colonic distension, air-fluid levels, and free intraabdominal air were assessed. Colonic wall thickening, contrast enhancement, pericolic stranding, and ascites were evaluated on CT. Laboratory parameters and clinical presentation were reviewed. Chi-square test, Student's t-test, McNemar's test and Spearman correlation were performed. Results: Colonic lumen distension was seen in 16/23 patients (69.6 %). The ascending colon (11/23 patients; 47.8 %) and transverse colon (12/23 patients; 52.2 %) were dilated significantly more often (p = 0.006 and p = 0.003, respectively) than the descending colon (1/23; 4.3 %). All 12 patients undergoing CT scanning had abnormally thickened colonic wall segments, 3 (25 %) had pancolic involvement and 9 (75 %) had segmental involvement. The descending colon was predominantly affected (11/12 patients; 91.7 %) and thickened significantly more often than other colonic segments (p < 0.001). Conclusion: The segmental type of STEC O104:H4 colitis mainly affects the descending colon with upstream distension of the transverse/ascending colon and differs from other types of colitis.
    RöFo - Fortschritte auf dem Gebiet der R 02/2013; · 2.76 Impact Factor

Publication Stats

2k Citations
444.44 Total Impact Points

Institutions

  • 2013–2014
    • University of Wuerzburg
      • Institute of Radiology
      Würzburg, Bavaria, Germany
  • 2010–2012
    • University Medical Center Hamburg - Eppendorf
      • Department of Diagnostic and Interventional Radiology
      Hamburg, Hamburg, Germany
  • 2009–2011
    • University of Wisconsin, Madison
      • Department of Radiology
      Madison, MS, United States
  • 2002–2010
    • University of Freiburg
      • Department of Rheumatology and Clinical Immunology
      Freiburg, Baden-Württemberg, Germany
  • 2006–2009
    • Universitätsklinikum Freiburg
      • Department of Radiology and Radiotherapy
      Freiburg, Lower Saxony, Germany
  • 2008
    • Max Planck Institute of Biochemistry
      München, Bavaria, Germany