Thorsten A Bley

University of Wuerzburg, Würzburg, Bavaria, Germany

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Publications (208)554.07 Total impact

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    ABSTRACT: Contrast-enhanced voiding urosonography (ce-VUS) is commonly requested simultaneously to other diagnostic imaging necessitating intravenous contrast agents. To date there is limited knowldedge about intravesical interactions between different types of contrast agents. To assess the effect of excreted intravenous iodinated and gadolinium-based contrast agents on the intravesical distribution of ultrasound contrast within contrast-enhanced voiding urosonography. Iodinated (iomeprol, iopamidol) and gadolinium-based (gadoterate meglumine) contrast agents were diluted to bladder concentration and injected into balloons filled with saline solution. CT scans were performed to assess the contrast distribution in these phantoms. Regions of interest were placed at the top and bottom side of each balloon and Hounsfield units (HU) were measured. Three other balloons were filled with saline solution and contrast media likewise. The ultrasound contrast agent sulphur hexafluoride was added and its distribution was assessed using sonography. MDCT scans showed a separation of two liquid layers in all bladder phantoms with the contrast layers located at the bottom and the saline solution at the top. Significant differences of the HU measurements at the top and bottom side were observed (P < 0.001-0.007). Following injection of ultrasound contrast agent, US showed its distribution exclusively among the saline solution. False-negative results of contrast-enhanced voiding urosonography may occur if it is performed shortly after imaging procedures requiring intravenous contrast.
    Pediatric Radiology 02/2015; DOI:10.1007/s00247-014-3243-2 · 1.65 Impact Factor
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    ABSTRACT: The aim of this study was to explore the applicability of fast MR techniques to routine paediatric abdominopelvic MRI at 1.5 Tesla. “Controlled Aliasing in Parallel Imaging Results in Higher Acceleration-” (CAIPIRINHA-) accelerated contrast-enhanced-T1w 3D FLASH imaging was compared to standard T1w 2D FLASH imaging with breath-holding in 40 paediatric patients and to respiratory-triggered T1w TSE imaging in 10 sedated young children. In 20 nonsedated patients, we compared T2w TIRM to fat-saturated T2w HASTE imaging. Two observers performed an independent and blinded assessment of overall image quality. Acquisition time was reduced by the factor of 15 with CAIPIRINHA-accelerated T1w FLASH and by 7 with T2w HASTE. With CAIPIRINHA and with HASTE, there were significantly less motion artefacts in nonsedated patients. In sedated patients, respiratory-triggered T1w imaging in general showed better image quality. However, satisfactory image quality was achieved with CAIPIRINHA in two sedated patients where respiratory triggering failed. In summary, fast scanning with CAIPIRINHA and HASTE presents a reliable high quality alternative to standard sequences in paediatric abdominal MRI. Paediatric patients, in particular, benefit greatly from fast image acquisition with less breath-hold cycles or shorter sedation.
    Gastroenterology Research and Practice 01/2015; 2015:1-6. DOI:10.1155/2015/693654 · 1.50 Impact Factor
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    ABSTRACT: Partial segmental thrombosis of the corpus cavernosum (PSTCC) is a rare disease predominantly occurring in young men. Cardinal symptoms are pain and perineal swelling. Although several risk factors are described in the literature, the exact etiology of penile thrombosis remains unclear in most cases. MRI or ultrasound (US) is usually used for diagnosing this condition. We report a case of penile thrombosis after left-sided varicocele ligature in a young patient. The diagnosis was established using contrast-enhanced ultrasound (CEUS) and was confirmed by contrast-enhanced magnetic resonance imaging (ceMRI). Successful conservative treatment consisted of systemic anticoagulation using low molecular weight heparin and acetylsalicylic acid. PSTCC is a rare condition in young men and appears with massive pain and perineal swelling. In case of suspected PSTCC utilization of CEUS may be of diagnostic benefit.
    BMC Urology 12/2014; 14(1):100. DOI:10.1186/1471-2490-14-100 · 1.94 Impact Factor
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    ABSTRACT: PURPOSE Annual imaging of the aortic root is recommended for Marfan patients. Unenhanced MRI allows for avoidance of nephrogenic systemic fibrosis, allergic reactions and contrast paravasation. In this context, we compared non-ECG-gated contrast-enhanced 3D MRA (CE-MRA) and ECG-gated non-contrast 2D steady-state-free precession (SSFP) imaging for monitoring of the aortic diameters in patients with Marfan syndrome (MFS). METHOD AND MATERIALS 3D CE-MRA and non-contrast 2D SSFP at 1.5T were prospectively performed in 50 patients with confirmed MFS (24 males; age 34.7±13.8). Two readers independently measured aortic diameters at the sinuses of Valsalva, sinutubular junction, ascending aorta, aortic arch and descending aorta. Image quality was assessed on a three-point scale at each level. Aortic root diameters acquired by echocardiography were used as reference standard. RESULTS Intra- and interobserver variances of measurements were significantly smaller for 2D SSFP at the sinuses of Valsalva (SSFP, 95% limit of agreement ±0.31cm vs. CE-MRA, ±0.69cm; p=0.002 and SSFP, 95% limit of agreement, ±0.37cm vs. CE-MRA, ±0.59cm; p=0.002) and sinutubular junction (p=0.014 and p=0.043). Image quality was rated significantly better for 2D SSFP than for 3D CE-MRA at sinuses of Valsalva (p<0.0001), sinutubular junction (p<0.0001) and ascending aorta (p=0.02). 3D CE-MRA yielded significantly higher diameters than 2D SSFP measurements at the sinuses of Valsalva (mean bias 0.25cm, p<0.0001), and comparison with echocardiography confirmed a higher bias (0.72±0.34cm) for 3D CE-MRA when compared to 2D SSFP (0.47±0.26cm). CONCLUSION ECG-gated non-contrast 2D SSFP imaging provides superior image quality with higher reproducibility and validity due to decreased motion artifacts compared to non-ECG-gated contrast-enhanced 3D imaging. Since 3D CE-MRA overestimates the diameter of the aortic root and requires administration of contrast agents with potential adverse effects, 2D SSFP imaging should be preferred for exact and riskless monitoring of aortic diameters in MFS patients. CLINICAL RELEVANCE/APPLICATION ECG-gated non-contrast 2D SSFP imaging should be preferred for monitoring of aortic diameters in Marfan patients.
    Radiological Society of North America 2014 Scientific Assembly and Annual Meeting; 12/2014
  • Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, Chicago; 12/2014
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    ABSTRACT: To compare 3.0 Tesla breast magnetic resonance imaging (MRI) with galactography for detection of benign and malignant causes of nipple discharge in patients with negative mammography and ultrasound. We prospectively evaluated 56 breasts of 50 consecutive patients with nipple discharge who had inconspicuous mammography and ultrasound, using 3.0 Tesla breast MRI with a dedicated 16-channel breast coil, and then compared the results with galactography. Histopathological diagnoses and follow-ups were used as reference standard. Lesion size estimated on MRI was compared with the size at histopathology. Sensitivity and specificity of MRI vs. galactography for detecting pathologic findings were 95.7 % vs. 85.7 % and 69.7 % vs. 33.3 %, respectively. For the supposed concrete pathology based on MRI findings, the specificity was 67.6 % and the sensitivity 77.3 % (PPV 60.7 %, NPV 82.1 %). Eight malignant lesions were detected (14.8 %). The estimated size at breast MRI showed excellent correlation with the size at histopathology (Pearson's correlation coefficient 0.95, p < 0.0001). MRI of the breast at 3.0 Tesla is an accurate imaging test and can replace galactography in the workup of nipple discharge in patients with inconspicuous mammography and ultrasound. • Breast MRI is an excellent diagnostic tool for patients with nipple discharge. • MRI of the breast reveals malignant lesions despite inconspicuous mammography and ultrasound. • MRI of the breast has greater sensitivity and specificity than galactography. • Excellent correlation of lesion size measured at MRI and histopathology was found.
    European Radiology 11/2014; DOI:10.1007/s00330-014-3521-2 · 4.34 Impact Factor
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    ABSTRACT: Purpose 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. Methods Non-ECG-gated CE-MRA and ECG-gated non-contrast SSFP at 1.5 T were prospectively performed in 50 patients. Two readers measured aortic diameters on para-sagittal images identically aligned with the aortic arch at the sinuses of Valsalva, sinotubular junction, ascending/descending aorta and aortic arch. Image quality was assessed on a three-point scale. Aortic root diameters acquired by echocardiography were used as reference. Results Intra- and interobserver variances were smaller for SSFP at the sinuses of Valsalva (p = 0.002; p = 0.002) and sinotubular junction (p = 0.014; p = 0.043). Image quality was better in SSFP than in CE-MRA at the sinuses of Valsalva (p p p = 0.02). CE-MRA yielded higher diameters than SSFP at the sinuses of Valsalva (mean bias, 2.5 mm; p Conclusion ECG-gated non-contrast 2D SSFP imaging provides superior image quality with higher validity compared to non-ECG-gated contrast-enhanced 3D imaging. Since CE-MRA requires contrast agents with potential adverse effects, non-contrast SSFP imaging is an appropriate alternative for exact and riskless aortic monitoring of MFS patients. Key Points • ECG-gated 2D SSFP imaging provides better image quality than non-ECG-gated contrast-enhanced 3D MRA • ECG-gated 2D SSFP imaging provides higher reproducibility than non-ECG-gated contrast-enhanced 3D MRA • 2D SSFP imaging provides higher validity than 3D MRA using echocardiography as reference • ECG-gated non-contrast 2D SFFP imaging allows for riskless monitoring of Marfan patients
    European Radiology 10/2014; 25(3). DOI:10.1007/s00330-014-3457-6 · 4.34 Impact Factor
  • DGMP 2014, Zurich; 09/2014
  • Der Radiologe 09/2014; 54(10). DOI:10.1007/s00117-014-2745-0 · 0.41 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; DOI:10.1148/radiol.14140056 · 6.21 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 08/2014; 27(8). DOI:10.1002/nbm.3134 · 3.56 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 08/2014; 72(2). DOI:10.1002/mrm.24938 · 3.40 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; DOI:10.1007/s00330-014-3323-6 · 4.34 Impact Factor
  • VASA.: Zeitschrift für Gefässkrankheiten. Journal for vascular diseases 07/2014; 43(4):298-302. DOI:10.1024/0301-1526/a000367 · 1.21 Impact Factor
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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; DOI:10.1016/j.mri.2014.05.012 · 2.02 Impact Factor
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    ABSTRACT: To assess deep temporal artery and temporalis muscle involvement in patients with giant cell arteritis (GCA). Ninety-nine patients who received magnetic resonance imaging (MRI) and superficial temporal artery biopsy (TAB) were included in this study. Patients with positive TAB (n = 61) were defined as GCA patients, those with negative TAB (n = 38) as the GCA-negative reference group. Contrast-enhanced T1w-images were acquired utilizing 1.5 T and 3 T MRI. Two radiologists assessed the images. Mural contrast-hyperenhancement and wall thickening of the deep temporal artery and hyperenhancement of the muscle were defined as inflammation. MRI results were correlated with jaw claudication in 70 patients. The two observers found temporalis muscle involvement in 19.7 % (n = 12) and 21.3 % (n = 13) of GCA patients. It occurred bilaterally in 100 %. Specificities were 92/97 % and sensitivities were 20/21 %. Deep temporal artery involvement was found in 34.4 % (n = 21) and 49.2 % (n = 30) and occurred bilaterally in 80/90.5 %. Specificities were 84/95 % and sensitivities were 34/49 %. Both structures were affected simultaneously in 18/21.3 %. Jaw claudication correlated moderately with inflammation of the temporalis muscle (r = 0.31; p < 0.05) and the deep temporal artery (r = 0.38; p = 0.01). MRI visualizes changes in the temporalis muscle and the deep temporal artery in GCA. Moderate correlation of clinical symptoms with MRI results was observed. aEuro cent Approximately 20 % of GCA patients presented with temporalis muscle inflammation. aEuro cent A total of 34-49 % of GCA patients presented with vasculitis of the deep temporal artery. aEuro cent In approximately 20 % of GCA patients, both structures were simultaneously involved. aEuro cent Involvement of both structures correlated moderately with presence of jaw claudication. aEuro cent MRI is a suitable tool for the assessment of vasculitis and muscle inflammation.
    European Radiology 06/2014; 24(11). DOI:10.1007/s00330-014-3255-1 · 4.34 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; 73(3). DOI:10.1002/mrm.25244 · 3.40 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2014; 186(S 01). DOI:10.1055/s-0034-1373078 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2014; 186(S 01). DOI:10.1055/s-0034-1372799 · 1.96 Impact Factor

Publication Stats

3k Citations
554.07 Total Impact Points

Institutions

  • 2014
    • University of Wuerzburg
      • Institute of Radiology
      Würzburg, Bavaria, Germany
  • 2010–2013
    • University Medical Center Hamburg - Eppendorf
      • Department of Diagnostic and Interventional Radiology
      Hamburg, Hamburg, Germany
    • University of Hamburg
      Hamburg, Hamburg, Germany
  • 2009–2013
    • Universitätsklinikum Freiburg
      • Department of Neuroradiology
      Freiburg an der Elbe, Lower Saxony, Germany
  • 2006–2013
    • University of Wisconsin–Madison
      • • Department of Radiology
      • • Department of Medical Physics
      Madison, Wisconsin, United States
  • 2003–2010
    • University of Freiburg
      • Department of Rheumatology and Clinical Immunology
      Freiburg, Baden-Württemberg, Germany
  • 2007
    • Emory University
      Atlanta, Georgia, United States