Thorsten A Bley

University of Wuerzburg, Würzburg, Bavaria, Germany

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Publications (225)573.41 Total impact

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    ABSTRACT: PurposeTo reduce saturation effects in the arterial input function (AIF) estimation of quantitative myocardial first-pass saturation recovery perfusion imaging by employing a model-based reconstruction.Theory and Methods Imaging was performed with a saturation recovery prepared radial FLASH sequence. A model-based reconstruction was applied for reconstruction. By exploiting prior knowledge about the relaxation process, an image series with different saturation recovery times was reconstructed. By evaluating images with an effective saturation time of approximately 3 ms, saturation effects in the AIF determination were reduced. In a volunteer study, this approach was compared with a standard prebolus technique.ResultsIn comparison to the low-dose injection of a prebolus acquisition, saturation effects were further reduced in the AIFs determined using the model-based approach. These effects, which were clearly visible for all six volunteers, were reflected in a statistically significant difference of up to 20% in the absolute perfusion values.Conclusion The application of model-based reconstruction algorithms in quantitative myocardial perfusion imaging promises a significant improvement of the AIF determination. In addition to greatly reducing saturation effects that occur even for the prebolus methods, only a single bolus has to be applied. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 09/2015; DOI:10.1002/mrm.25921 · 3.57 Impact Factor
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    ABSTRACT: Purpose: The role of myocardial triglyceride (mTG) content in the aging human heart is not entirely understood. The aim of this study was to measure concentrations of mTG content from healthy volunteers and to determine the association between age, mTG content and systolic heart function. Furthermore, the technical stability of the (1)H-magnetic resonance spectroscopy ((1)H-MRS) and the reliability of peak evaluation at 3 T were evaluated. Materials and Methods: The total study population of 47 healthy volunteers was divided into 4 age classes, according to the age of the subjects (1(st) cohort 20 - 29 years (yrs.), n = 20; 2(nd) cohort 30 - 39 yrs., n = 10; 3(rd) cohort 40 - 49 yrs., n = 9; 4(th) cohort 50 - 60 yrs., n = 8). Cardiac MRI and double triggered (1)H-MRS of the myocardium were consecutively performed using a 3 T scanner. Each participant underwent spectroscopic measurements twice in the same investigation. Results: mTG content increases with age. The correlation of age and mTG is minimal (r = 0.48; p < 0.001). The following age-averaged mTG content values expressed as % of mTG signal compared to the water signal were determined for each cohort: 1(st) cohort 0.25 % (± 0.17); 2(nd) cohort 0.48 % (± 0.30); 3(rd) cohort 0.48 % (± 0.18); 4(th) cohort 0.77 % (± 0.70). There was no significant correlation (r = 0.04; p = n.s.) between LV mass and mTG content in healthy volunteers. Within our cohorts, no effects of age or mTG content on systolic heart function were seen (r = - 0.01; p = n.s.). The intraclass correlation coefficient of spectroscopic measurements was high (r = 0.965; p < 0.001). Conclusion: Myocardial TG content increases with age. The normal age-dependent concentration ranges of myocardial lipid metabolites reported in this study may be helpful for the correction of acquired (1)H-MRS data in patients when evaluating metabolic and cardiovascular diseases in future magnetic resonance spectroscopy studies. Key Points: • (1)H-MRS enables noninvasive myocardial lipid determination• Double triggered (1)H-MRS of the heart at 3 T is a technically stable and reliable method• Myocardial triglyceride content increases with age• Myocardial triglyceride content is independent of LV mass and systolic function Citation Format: • Petritsch B, Gassenmaier T, Kunz AS et al. Age Dependency of Myocardial Triglyceride Content: A 3T High-Field (1)H-MR Spectroscopy Study. Fortschr Röntgenstr 2015; DOI: 10.1055/s-0035-1553350. © Georg Thieme Verlag KG Stuttgart · New York.
    RöFo - Fortschritte auf dem Gebiet der R 07/2015; DOI:10.1055/s-0035-1553350 · 1.40 Impact Factor
  • R Kickuth · C Reichling · T Bley · D Hahn · C Ritter ·
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    ABSTRACT: Purpose: To evaluate the feasibility and efficacy of C-arm fluoroscopic cone-beam computed tomography (CACT) in combination with a new electromagnetic tracking (EMT) system for needle guidance during percutaneous biopsies. Materials and Methods: 53 patients were referred for biopsy of thoracic (n = 19) and abdominal (n = 34) lesions. CT-like images of the anatomical region of interest (ROI) were generated using a flat panel-based angiographic system. These images were transmitted to an EMT system. A coaxial puncture needle with a sensor in its tip was connected with the navigation system and tracked into an electromagnetic field created via a field generator. Data generated within this field were merged with the CACT images. On a monitor both the anatomical ROI and needle tip position were displayed to enable precise needle insertion into the target. Through the coaxial needle, biopsy specimens for the histologic evaluation were extracted. Number of representative biopsy samples, number of core biopsies/patient, total procedure time, dose-area product, fluoroscopic time, and complications were recorded. Results: 53 CACT/EMT-guided biopsy procedures were performed, 48 of which (91 %) yielded representative tissue samples. Four core biopsies were obtained from each patient. 40 (75 %) lesions were malignant and 13 (25 %) lesions were benign. The total procedure time was 9 ± 5 min (range, 3 - 23 min), fluoroscopic time was 0.8 ± 0.4 min (range, 0.4 - 2 min). The mean dose-area product (cGy cm²) was 7373 (range, 895 - 26 904). The rate of complications (1 pneumothorax, 2 hemoptyses) was 6 %. Conclusion: CACT combined with EMT appears to be a feasible and effective technique for the guidance of percutaneous biopsies with a low rate of therapeutically relevant complications. Key Points: • Guidance of percutaneous biopsies with a combination of CACT and EMT is technically feasible.• CACT/EMT-guided biopsies are associated with a good diagnostic yield.• The rate of complications appears to be low for this guidance technique. Citation Format: • Kickuth R., Reichling C., Bley T. et al. C-Arm Cone-Beam CT Combined with a New Electromagnetic Navigation System for Guidance of Percutaneous Needle Biopsies: Initial Clinical Experience. Fortschr Röntgenstr 2015; 187: 569 - 576. © Georg Thieme Verlag KG Stuttgart · New York.
    RöFo - Fortschritte auf dem Gebiet der R 07/2015; 187(7):569-576. DOI:10.1055/s-0034-1399313 · 1.40 Impact Factor
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    ABSTRACT: To compare 3D-inversion-recovery balanced steady-state free precession (IR-bSSFP) non-contrast-enhanced magnetic resonance angiography (MRA) with 3D-contrast-enhanced MRA (CE-MRA) for assessment of renal artery stenosis (RAS) using digital subtraction angiography (DSA) as the reference standard. Bilateral RAS were surgically created in 12 swine. IR-bSSFP and CE-MRA were acquired at 1.5 T and compared to rotational DSA. Three experienced cardiovascular radiologists evaluated the IR-bSSFP and CE-MRA studies independently. Linear regression models were used to calibrate and assess the accuracy of IR-bSSFP and CE-MRA, separately, against DSA. The coefficient of determination and Cohen's kappa coefficient were also generated. Calibration of the three readers' RAS grading revealed R(2) values of 0.52, 0.37 and 0.59 for NCE-MRA and 0.48, 0.53 and 0.71 for CE-MRA. Inter-rater agreement demonstrated Cohen's kappa values ranging from 0.25 to 0.65. Distal renal artery branch vessels were visible to a significantly higher degree with NCE-MRA compared to CE-MRA (p < 0.001). Image quality was rated excellent for both sequences, although image noise was higher with CE-MRA (p < 0.05). In no cases did noise interfere with image interpretation. In a well-controlled animal model of surgically induced RAS, IR-bSSFP based NCE-MRA and CE-MRA accurately graded RAS with a tendency for stenosis overestimation, compared to DSA. • IR-bSSFP and CE-MRA are accurate methods for diagnosis of renal artery stenosis • IR-bSSFP and CE-MRA demonstrate excellent agreement with DSA • Both IR-bSSFP and CE-MRA have a tendency to overestimate renal artery stenosis.
    European Radiology 05/2015; DOI:10.1007/s00330-015-3833-x · 4.01 Impact Factor
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    ABSTRACT: Neoadjuvant therapy could improve oncological outcome of patients suffering from colon cancer. An accurate staging method is needed to define suitable patients. The aim of this retrospective study was to validate the value of CT for identifying patients with local advanced (T3/4) or nodal-positive colon cancer. Preoperative abdominal CT scans of 210 patients with colon cancer were evaluated by two radiologists independently for the T stage and N stage. Results were compared to pathology. Patients were stratified according to the guidelines for rectal cancer into patients with low risk (T0/1/2 and N0) or high risk (T3/4 or N+). Inter-observer correlation was high with over 90 %. Overall sensitivity T stage was 93.0 % and for N stage 76.9 %. Using CT scan to identify local advanced (T3/4 or N+) tumors, the consensus sensitivity was 94.9 %, the specificity 53.6 %, the positive predictive value (PPV) 92.8 %, and the negative predictive value (NPV) 62.5 %. Computer tomography represents an effective tool for identifying patients with colon cancer suitable for neoadjuvant therapy according to the guidelines for rectal cancer.
    International Journal of Colorectal Disease 05/2015; 30(8). DOI:10.1007/s00384-015-2265-z · 2.45 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 05/2015; 2015:1-6. DOI:10.1155/2015/693654 · 1.75 Impact Factor
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    ABSTRACT: Purpose To evaluate the feasibility, effectiveness, and safety of using a commercially available reentry catheter with fluoroscopic guidance to gain controlled target lumen reentry for fenestration in patients with aortic dissection. Materials and Methods This retrospective study was approved by the local institutional review board; informed consent was waived. Between April 2009 and December 2013, 13 consecutive patients (10 men and three women; mean age, 51.2 years; range, 30.0-77.0 years; mean age of women, 47.0 years; range, 30.0-69.0 years; mean age of men, 52.4 years; range, 35.0-77.0 years) with aortic dissection and spinal (n = 4), renal (n = 7), mesenteric (n = 2), and/or iliofemoral (n = 9) malperfusion syndrome were included. All patients received target lumen reentry by means of balloon fenestration of the aortic dissection flap. A reentry catheter was used for fluoroscopically guided puncture of the target lumen. Technical success, clinical outcome, Stanford type of dissection, procedure time, number of fenestrations of the intimal flap per patient, necessity of additional aortic stent-graft implantation and/or placement of a bare metal stent, complications, and follow-up images were evaluated. Pre- and postinterventional systolic blood pressure gradients between the true lumen and the false lumen were compared (Wilcoxon signed-rank test). Safety of the reentry catheter maneuver was estimated with the Clopper-Pearson method. Results Use of the reentry catheter was technically successful in all 13 (100%) patients and clinically successful in 10 of 13 (77%) patients. Four patients had type A and nine had type B dissection. The mean clinical follow-up period was 14.2 months. Median procedure time was 71 minutes. In four patients, fenestration of the intimal flap was performed twice. Three patients underwent additional aortic stent grafting, four patients underwent placement of an iliofemoral stent, and one patient underwent placement of a carotid artery stent. Blood pressure gradients between the true lumen and the false lumen were significantly reduced (P = .0313). One patient who had a combination of syndromes died of multiorgan failure. Conclusion The applied commercially available reentry catheter seems to be a reliable and safe tool that may be useful for gaining target lumen reentry with reasonably good clinical outcomes. (©) RSNA, 2015.
    Radiology 04/2015; 276(3):140520. DOI:10.1148/radiol.2015140520 · 6.87 Impact Factor
  • S Herz · P Vogel · C Brede · T Kampf · M Rückert · S Veldhoen · P Jakob · V Behr · A Beilhack · T Bley ·

    RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1550867 · 1.40 Impact Factor
  • A Dierks · A Sauer · F Wolfschmidt · N Hassold · T Bley · R Kickuth ·

    RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1551113 · 1.40 Impact Factor

  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1551133 · 1.40 Impact Factor
  • F Wolfschmidt · A Dierks · A Sauer · T Bley · R Kickuth ·

    RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1551070 · 1.40 Impact Factor
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    Johannes Tran-Gia · Tobias Wech · Thorsten Bley · Herbert Köstler ·
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    ABSTRACT: Mapping the longitudinal relaxation time T1 has widespread applications in clinical MRI as it promises a quantitative comparison of tissue properties across subjects and scanners. Due to the long scan times of conventional methods, however, the use of quantitative MRI in clinical routine is still very limited. In this work, an acceleration of Inversion-Recovery Look-Locker (IR-LL) T1 mapping is presented. A model-based algorithm is used to iteratively enforce an exponential relaxation model to a highly undersampled radially acquired IR-LL dataset obtained after the application of a single global inversion pulse. Using the proposed technique, a T1 map of a single slice with 1.6mm in-plane resolution and 4mm slice thickness can be reconstructed from data acquired in only 6s. A time-consuming segmented IR experiment was used as gold standard for T1 mapping in this work. In the subsequent validation study, the model-based reconstruction of a single-inversion IR-LL dataset exhibited a T1 difference of less than 2.6% compared to the segmented IR-LL reference in a phantom consisting of vials with T1 values between 200ms and 3000ms. In vivo, the T1 difference was smaller than 5.5% in WM and GM of seven healthy volunteers. Additionally, the T1 values are comparable to standard literature values. Despite the high acceleration, all modelbased reconstructions were of a visual quality comparable to fully sampled references. Finally, the reproducibility of the T1 mapping method was demonstrated in repeated acquisitions. In conclusion, the presented approach represents a promising way for fast and accurate T1 mapping using radial IR-LL acquisitions without the need of any segmentation.
    PLoS ONE 04/2015; 10(4):e0122611. DOI:10.1371/journal.pone.0122611 · 3.23 Impact Factor
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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; 45(6). DOI:10.1007/s00247-014-3243-2 · 1.57 Impact Factor

  • IWMPI 2015, Istanbul; 01/2015

  • DGMP 2015, Marburg; 01/2015

  • RSNA 2015, Chicago; 01/2015
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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 · 1.41 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

Publication Stats

3k Citations
573.41 Total Impact Points


  • 2013-2015
    • University of Wuerzburg
      • Institute of Radiology
      Würzburg, Bavaria, Germany
  • 2010-2014
    • University Medical Center Hamburg - Eppendorf
      • • Department of Diagnostic and Interventional Neuroradiology
      • • Department of Diagnostic and Interventional Radiology
      Hamburg, Hamburg, Germany
  • 2006-2013
    • University of Wisconsin–Madison
      • • Department of Radiology
      • • Department of Medical Physics
      Madison, Wisconsin, United States
  • 2010-2011
    • University of Hamburg
      Hamburg, Hamburg, Germany
  • 2003-2010
    • University of Freiburg
      • Department of Rheumatology and Clinical Immunology
      Freiburg, Baden-Württemberg, Germany
  • 2005-2009
    • Universitätsklinikum Freiburg
      • Department of Neuroradiology
      Freiburg an der Elbe, Lower Saxony, Germany