Matthias K Werner

Universitätsklinikum Tübingen, Tübingen, Baden-Württemberg, Germany

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Publications (25)62.65 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Purpose: In patients with a neuroendocrine tumour (NET), the extent of disease strongly influences the outcome and multidisciplinary therapeutic management. Thus, systematic analysis of the diagnostic performance of the existing staging modalities is necessary. The aim of this study was to compare the diagnostic performance of 2 whole-body imaging modalities, [Ga]DOTATOC positron emission tomography (PET)/computed tomography (CT) and magnetic resonance imaging (MRI) in patients with NET with regard to possible impact on treatment decisions. Materials and methods: [Ga]DOTATOC-PET/CT and whole-body magnetic resonance imaging (wbMRI) were performed on 51 patients (25 females, 26 males, mean age 57 years) with histologically proven NET and suspicion of metastatic spread within a mean interval of 2.4 days (range 0-28 days). PET/CT was performed after intravenous administration of 150 MBq [Ga]DOTATOC. The CT protocol comprised multiphase contrast-enhanced imaging. The MRI protocol consisted of standard sequences before and after intravenous contrast administration at 1.5 T. Each modality (PET, CT, PET/CT, wbMRI) was evaluated independently by 2 experienced readers. Consensus decision based on correlation of all imaging data, histologic and surgical findings and clinical follow-up was established as the standard of reference. Lesion-based and patient-based analysis was performed. Detection rates and accuracy were compared using the McNemar test. P values <0.05 were considered significant. The impact of whole-body imaging on the treatment decision was evaluated by the interdisciplinary tumour board of our institution. Results: 593 metastatic lesions were detected in 41 of 51 (80%) patients with NET (lung 54, liver 266, bone 131, lymph node 99, other 43). One hundred and twenty PET-negative lesions were detected by CT or MRI. Of all 593 lesions detected, PET identified 381 (64%) true-positive lesions, CT 482 (81%), PET/CT 545 (92%) and wbMRI 540 (91%). Comparison of lesion-based detection rates between PET/CT and wbMRI revealed significantly higher sensitivity of PET/CT for metastatic lymph nodes (100% vs 73%; P < 0.0001) and pulmonary lesions (100% vs 87%; P = 0.0233), whereas wbMRI had significantly higher detection rates for liver (99% vs 92%; P < 0.0001) and bone lesions (96% vs 82%; P < 0.0001). Of all 593 lesions, 22 were found only in PET, 11 only in CT and 47 only in wbMRI. The patient-based overall assessment of the metastatic status of the patient showed comparable sensitivity of PET/CT and MRI with slightly higher accuracy of PET/CT. Patient-based analysis of metastatic organ involvement revealed significantly higher accuracy of PET/CT for bone and lymph node metastases (100% vs 88%; P = 0.0412 and 98% vs 78%; P = 0.0044) and for the overall comparison (99% vs 89%; P < 0.0001). The imaging results influenced the treatment decision in 30 patients (59%) with comparable information from PET/CT and wbMRI in 30 patients, additional relevant information from PET/CT in 16 patients and from wbMRI in 7 patients. Conclusion: PET/CT and wbMRI showed comparable overall lesion-based detection rates for metastatic involvement in NET but significantly differed in organ-based detection rates with superiority of PET/CT for lymph node and pulmonary lesions and of wbMRI for liver and bone metastases. Patient-based analysis revealed superiority of PET/CT for NET staging. Individual treatment strategies benefit from complementary information from PET/CT and MRI.
    Cancer Imaging 01/2013; 13:63-72. · 1.59 Impact Factor
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    ABSTRACT: PURPOSE: Combined PET/CT imaging has been proposed as an integral part of radiotherapy treatment planning (TP). Contrast-enhanced CT (ceCT) images are frequently acquired as part of the PET/CT examination to support target delineation. The aim of this dosimetric planning study was to investigate the error introduced by using a ceCT for intensity modulated radiotherapy (IMRT) TP with Monte Carlo dose calculation for non-small cell lung cancer (NSCLC). MATERIAL AND METHODS: Nine patients with NSCLC prior to chemo-RT were included in this retrospective study. For each patient non-enhanced, low-dose CT (neCT), ceCT and [(18)F]-FDG-PET emission data were acquired within a single examination. Manual contouring and TP were performed on the ceCT. An additional set of independent target volumes was auto-segmented in PET images. Dose distributions were recalculated on the neCT. Differences in dosimetric parameters were evaluated. RESULTS: Dose differences in PTV and lungs were small for all patients. The maximum difference in all PTVs when using ceCT images for dose calculation was -2.1%, whereas the mean difference was less than -1.7%. Maximum differences in the lungs ranged from -1.8% to 2.1% (mean: -0.1%). In four patients an underestimation of the maximum spinal cord dose between 2% and 3.2% was observed, but treatment plans remained clinically acceptable. CONCLUSIONS: Monte Carlo based IMRT planning for NSCLC patients using ceCT allows for correct dose calculation. A direct comparison to neCT-based treatment plans revealed only small dose differences. Therefore, ceCT-based TP is clinically safe as long as the maximum acceptable dose to organs at risk is not approached.
    Physica Medica 09/2012; · 1.17 Impact Factor
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    ABSTRACT: Clinical PET/MR acquisition protocols entail the use of MR contrast agents (MRCA) that could potentially affect PET quantification following MR-based attenuation correction (AC). We assessed the effect of oral and intravenous (IV) MRCA on PET quantification in PET/MR imaging. We employed two MRCA: Lumirem® (oral) and Gadovist® (IV). First, we determined their reference PET attenuation values using a PET transmission scan (ECAT-EXACT HR+, Siemens) and a CT scan (PET/CT Biograph 16 HI-REZ, Siemens). Second, we evaluated the attenuation of PET signals in the presence of MRCA. Phantoms were filled with clinically relevant concentrations of MRCA in a background of water and (18)F-fluoride, and imaged using a PET/CT scanner (Biograph 16 HI-REZ, Siemens) and a PET/MR scanner (Biograph mMR, Siemens). Third, we investigated the effect of clinically relevant volumes of MRCA on MR-based AC using human pilot data: a patient study employing Gadovist® (IV) and a volunteer study employing two different oral MRCA (Lumirem® and pineapple juice). MR-based attenuation maps were calculated following Dixon-based fat-water segmentation and an external atlas-based and pattern recognition (AT&PR) algorithm. IV and oral MRCA in clinically relevant concentrations were found to have PET attenuation values similar to those of water. The phantom experiments showed that under clinical conditions IV and oral MRCA did not yield additional attenuation of PET emission signals. Patient scans showed that PET attenuation maps are not biased after the administration of IV MRCA but may be biased, however, after ingestion of iron oxide-based oral MRCA when segmentation-based AC algorithms are used. Alternative AC algorithms, such as AT&PR, or alternative oral contrast agents, such as pineapple juice, can yield unbiased attenuation maps. In clinical PET/MR scenarios MRCA are not expected to lead to markedly increased attenuation of the PET emission signals. MR-based attenuation maps may be biased by oral iron oxide-based MRCA unless advanced AC algorithms are used.
    European Journal of Nuclear Medicine 08/2012; 39(11):1756-66. · 4.53 Impact Factor
  • Matthias K Werner, Holger Schmidt, Nina F Schwenzer
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    ABSTRACT: OBJECTIVE: This article provides a short overview of hybrid imaging and the potential advantages of combined MR/PET. We will address some of the challenges that had to be met before MR/PET could become clinically available as well as further scientific work that has to be done to increase the potential benefit of this emerging hybrid modality. CONCLUSION: Hybrid imaging, the combination of two imaging modalities into one, promises the compensation of specific deficits of the modalities involved. PET/CT has gained wide acceptance for oncologic imaging in recent years; however, MRI has certain advantages that could make combined MR/PET more tempting in various clinical applications. The development of new clinical whole-body MR/PET systems offers new insights in metabolic and functional processes in oncology as well as cardiovascular and neurologic diseases.
    American Journal of Roentgenology 08/2012; 199(2):272-7. · 2.90 Impact Factor
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    ABSTRACT: The present review aims to depict the possibilities offered by hybrid imaging with magnetic resonance positron emission tomography (MR/PET). Recently, new whole-body MR/PET scanners were introduced allowing for the combination of both modalities outside the brain. This is a challenge for both modalities: For MRI, it is essential to provide anatomical images with high resolution. Additionally, diffusion-weighted imaging (DWI), proton spectroscopy, but also dynamic contrast-enhanced imaging plays an important role. With regard to PET, the technical challenge mainly consists of obtaining an appropriate MR-based attenuation correction for the PET data. Using MR/PET, it is possible to acquire morphological and functional data in one examination. In particular, children and young adults will benefit from this new hybrid technique, especially in oncologic imaging with multiple follow-up examinations. However, it is expected that PET/CT will not be replaced completely by MR/PET because PET/CT is less cost-intensive and more widely available. Moreover, in lung imaging, MRI limitations still have to be accepted. Concerning research, simultaneous MR/PET offers a variety of new possibilities, for example cardiac imaging, functional brain studies or the evaluation of new tracers in correlation with specific MR techniques.
    RöFo - Fortschritte auf dem Gebiet der R 05/2012; 184(9):780-7. · 2.76 Impact Factor
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    ABSTRACT: PURPOSE: To evaluate the accuracy of presurgical endorectal MRI (eMRI) for local staging before radical prostatectomy (RP) and its influence on neurovascular bundle (NVB) resection during radical prostatectomy. PATIENTS AND METHODS: A total of 385 patients with histologically proven prostate cancer (PCa) have been included in this retrospective study between 2004 and 2008. All patients underwent preoperative eMRI at 1.5 T before open RP. Staging results by eMRI were compared with the histopathological findings. The presence of positive surgical margins and extent of nerve-sparing procedure were evaluated. Subgroup analysis of low-risk group and intermediate to high-risk group based on D'Amico criteria was conducted. RESULTS: In 294 (76.4%) patients, pathological stage was correctly predicted, 69 patients (17.9%) were understaged and 22 (5.7%) overstaged. Overall sensitivity, specificity, negative and positive predictive value for predicting extracapsular extension (ECE) were 41.5, 91.8, 78.0 and 69.0%, respectively. One hundred and fifty-two (48.4%) of the patients classified as stage cT2 by eMRI underwent bilateral NVB sparing, whereas 14 (19.7%) patients with reported ECE underwent bilateral NVB sparing (P < 0.01). Overall positive surgical margin rate was 14.8%. Sensitivity of predicting ECE and positive predictive value were lower in the low-risk group than in the intermediate and high-risk group. CONCLUSIONS: eMRI is effective in predicting extracapsular extension in an intermediate to high-risk group. Preoperative eMRI in patients with low-risk criteria is not recommended as a routine assessment modality. eMRI findings did appear to influence surgical strategy as patients with imaging findings suggesting >cT2 disease were less likely to undergo NVB sparing.
    World Journal of Urology 01/2012; · 2.89 Impact Factor
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    ABSTRACT: To investigate the positive biopsy rate of MRI-guided biopsy (MR-GB) in a routine clinical setting, identify factors predictive for positive biopsy findings and to report about the clinical significance of the diagnosed tumors. Patients with at least one negative trans-rectal-ultrasound-guided biopsy (TRUS-GB), persistently elevated or rising serum prostate specific antigen (PSA) and at least one lesion suspicious for PCa on diagnostic 1.5 Tesla endorectal coil MRI (eMR) were included. Biopsies were carried out using a 1.5 Tesla MRI and an 18 G biopsy gun. Clinical information and biopsy results were collected; logistic regression analysis was carried out. Definite pathology reports of patients with diagnosis of PCa and subsequent radical prostatectomy (RP) were analyzed for criteria of clinical significance. One hundred patients were included, mean number of previous biopsies was 2 (range 1-9), mean PSA at time of biopsy was 11.7 ng/ml (1.0-65.0), and mean prostate volume was 46.7 ccm (range 13-183). In 52/100 (52.0%) patients, PCa was detected. Out of 52 patients, 27 patients with a positive biopsy underwent RP, 20 patients radiation therapy, and 5 patients active surveillance. In total, 80.8% of the patients revealed a clinically significant PCa. In univariate regression analysis, only serum PSA levels were predictive for a positive biopsy result. Number of preceding negative biopsies was not associated with the likelihood of a positive biopsy result. MR-GB shows a high detection rate of clinically significant PCa in patients with previous negative TRUS-GB and persisting suspicion for PCa.
    World Journal of Urology 04/2011; 30(2):213-8. · 2.89 Impact Factor
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    ABSTRACT: A 73-year-old man with a history of prostate and bladder carcinoma and persistent back pain was diagnosed by MRI with multiple vertebral metastases including a compression fracture of T7. He received radiotherapy for pain relief and for vertebral instability with incipient spinal stenosis, but additional targeted systemic therapy was intended. Therefore, multiple attempts at minimally invasive and open biopsies for histological characterisation of the bone metastases were performed, but failed to provide a conclusive specimen, although CT, MRI and bone scintigraphy were used for biopsy planning. Only histopathological analysis of an (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT-guided additional biopsy at a site with high metabolic activity yielded the final diagnosis of bone metastases of a neuroendocrine small cell cancer of unknown origin; hence, the patient had a third malignancy requiring a different therapy regimen and diagnostic work-up.
    The British journal of radiology 03/2011; 84(999):e65-7. · 2.11 Impact Factor
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    ABSTRACT: A 43-year-old man was hospitalized for Sjögren’s syndrome which wassuspectedtobeof paraneoplastic aetiology. 18 F-FDG PET/CT revealed grossly enlarged lacrimal (a) and parotid glands (b) with significantly increased FDG uptake while the submandibular glands (c) were only minimally enlarged with faint FDG uptake. Furthermore, hypermetabolic intrathoracic lymphadenopathy was detected with a typical lambda appearance (h) involving right paratracheal (e), left paratracheal and aortopulmonary window lymph nodes (f) of the mediastinum and bihilar lymph nodes (g). The imaging findings were suggestive of sarcoidosis and bronchoscopic evaluation with biopsy was proposed. Histopathology of a transbronchial biopsy specimen confirmed the diagnosis of sarcoidosis. In 1990 Sulavik et al. first described the panda sign, i.e. normal accumulation of the radionuclide ( 67 Ga-citrate) in the nasopharynx combined with increased symmetric accumulation in the parotid and lacrimal glands, giving the impression of the mottled colouring of the giant panda [1–3]. Intrathoracic lymphadenopathy typically manifests as bilateral hilar adenopathywithpredominantlyrightparatrachealadenopathy,
    European Journal of Nuclear Medicine 03/2011; 38(3):603. · 4.53 Impact Factor
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    ABSTRACT: Clinical PET/MR requires the use of patient positioning aids to immobilize and support patients for the duration of the combined examination. Ancillary immobilization devices contribute to overall attenuation of the PET signal, but are not detected with conventional MR sequences and, hence, are ignored in standard MR-based attenuation correction (MR-AC). We report on the quantitative effect of not accounting for the attenuation of patient positioning aids in combined PET/MR imaging. We used phantom and patient data acquired with positioning aids on a PET/CT scanner (Biograph 16, HI-REZ) to mimic PET/MR imaging conditions. Reference CT-based attenuation maps were generated from measured (original) CT transmission images (origCT-AC). We also created MR-like attenuation maps by following the same conversion procedure of the attenuation values except for the prior delineation and subtraction of the positioning aids from the CT images (modCT-AC). First, a uniform (68)Ge cylinder was positioned centrally in the PET/CT scanner and fixed with a vacuum mattress (10 cm thick) and, in a repeat examination, with MR positioning foam pads. Second, 16 patient datasets were selected for subsequent processing. All patients were regionally immobilized with positioning aids: a vacuum mattress for head/neck imaging (nine patients) and a foam mattress for imaging of the lower extremities (seven patients). PET images were reconstructed following CT-based attenuation and scatter correction using the original and modified (MR-like) CT images: PET(origCT-AC) and PET(modCT-AC), respectively. PET images following origCT-AC and modCT-AC were compared visually and in terms of mean differences of voxels with a standardized uptake value of at least 1.0. In addition, we report maximum activity concentration in lesions for selected patients. In the phantom study employing the vacuum mattress the average voxel activity in PET(modCT-AC) was underestimated by 6.4% compared to PET(origCT-AC), with 3.4% of the PET voxels being underestimated by 10% or more. When the MR foam pads were not accounted for during AC, PET(modCT-AC) was underestimated by 1.1% on average, with none of the PET voxels being underestimated by 10% or more. Evaluation of the head/neck patient data showed a decrease of 8.4% ([(68)Ga]DOTATOC) and 7.4% ([(18)F]FDG) when patient positioning aids were not accounted for during AC, while the corresponding decrease was insignificant for the lower extremities. Depending on the size and density of the positioning aids used, a regionally variable underestimation of PET activity following AC is observed when positioning aids are not accounted for. This underestimation may become relevant in combined PET/MR imaging of patients with neuropsychiatric indications, but appears to be of no clinical relevance in imaging the extremities.
    European Journal of Nuclear Medicine 02/2011; 38(5):920-9. · 4.53 Impact Factor
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    ABSTRACT: For cancers of the head and neck, the combination of (18)F-fluorodeoxy-glucose positron emission tomography (FDG-PET)/computed tomography (CT) gains wide acceptance, especially if the primary tumor is unknown (CUP). A patient underwent FDG-PET/CT for squamous cell CUP with cervical lymph node metastases. FDG-PET/CT showed uptake in the right side of the tongue, rendering this area a possible location for the primary tumor. However, clinical examination revealed a deviation of the tongue toward the left side indicating affection of the left hypoglossal nerve, causing the increased FDG uptake. This case illustrates the interpretive pitfalls of unspecific FDG uptake in PET/CT imaging of the head and neck.
    Clinical imaging 01/2011; 35(5):405-7. · 0.73 Impact Factor
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    ABSTRACT: Purpose: To compare the diagnostic performance of [68Ga]DOTA-d-Phe(1)-Tyr(3)-octreotide (DOTATOC)-positron emission tomography (PET)/computed tomography (CT) and whole-body (wb) magnetic resonance imaging (MRI) in staging of neuroendocrine tumors (NET). Material and methods: In 51 patients with histologically proven NET and suspicion of metastatic spread [68Ga]DOTATOC-PET/CT and wbMRI were performed within 30 days. PET/CT was performed after 150 MBq [68Ga]DOTATOC intravenously and included multiphase contrast-enhanced CT. The MRI protocol comprised standard sequences before and after contrast at 1.5 T. Each modality was evaluated separately and blindly with regard to metastatic lesion detection. Histology, clinical and imaging follow-up and consensus evaluation of all examinations served as reference standard. Lesion-based comparison of overall and site-based detection rates of PET/CT and wbMRI was performed using the McNemar test. Results: 41 of 51 (80%) NET patients had 593 metastatic lesions (54 lung, 266 liver, 131 bone, 99 lymph node, 43 other). [68Ga]DOTATOC-PET was false-negative in 5/41 (12%) patients due to the lack of somatostatin receptor (SSTR) expression. PET/CT and wbMRI showed comparable overall detection rates (92% vs 91%). Comparison of organ-based evaluation revealed significantly higher sensitivity of PET/CT in detecting metastatic lymph nodes (100% vs 73%) and pulmonary lesions (100% vs 87%) while wbMRI had significantly higher detection rates for liver (99% vs 92%) and bone lesions (96% vs 82%). If only SSTR+ patients were considered, the overall detection rate of PET/CT significantly improved. Conclusion: PET/CT and wbMRI showed comparable overall detection rates for metastatic involvement in NET but significantly differed in organ-based detection rates with superiority of PET/CT for LN and pulmonary lesions and wbMRI for liver and bone metastases.
    Cancer Imaging 01/2011; 11 Spec No A:S38-9. · 1.59 Impact Factor
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    ABSTRACT: Although metastatic carcinoma is the most common malignant tumor of the bone, less than 1% of all metastatic bone lesions are presented in the maxillofacial area. As the mandibular body is the most frequent localization, metastasis to the mandibular condyle is extremely rare. This report describes a rare case of prostate carcinoma metastatic to the mandibular condyle in a 75-year old man, who was referred because of persistent pain in the temporomandibular joint (TMJ) region and a limitation of opening, initially misdiagnosed and treated as temporomandibular disorder (TMD). Histopathological examination confirmed the suspected metastasis of prostate carcinoma and local radiation therapy was performed. TMD represent a diagnostic challenge and sometimes an interdisciplinary approach is required to prevent a delay of the correct treatment. Metastatic cancer should be included in the differential diagnosis of TMD, especially in patients with a malignant disease.
    Oral and Maxillofacial Surgery 12/2010; 16(1):79-82.
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    ABSTRACT: In dual energy (DE) computed tomography (CT), spectral shaping by additional filtration of the high energy spectrum can theoretically improve dual energy contrast. The aim of this in vitro study was to examine the influence of an additional tin filter for the differentiation of human urinary calculi by dual energy CT. A total of 36 pure human urinary calculi (uric acid, cystine, calciumoxalate monohydrate, calciumoxalate dihydrate, carbonatapatite, brushite, average diameter 10.5 mm) were placed in a phantom and imaged with 2 dual source CT scanners. One scanner was equipped with an additional tin (Sn) filter. Different combinations of tube voltages (140/80 kV, 140/100 kV, Sn140/100 kV, Sn140/80 kV, with Sn140 referring to 140 kV with the tin filter) were applied. Tube currents were adapted to yield comparable dose indices. Low- and high energy images were reconstructed. The calculi were segmented semiautomatically in the datasets and DE ratios (attenuation@low_kV/attenuation@high_kV) and were calculated for each calculus. DE contrasts (DE-ratio_material1/DE-ratio_material2) were computed for uric acid, cystine and calcified calculi and compared between the combinations of tube voltages. Using exclusively DE ratios, all uric acid, cystine and calcified calculi (as a group) could be differentiated in all protocols; the calcified calculi could not be differentiated among each other in any examination protocol. The highest DE ratios and DE contrasts were measured for the Sn140/80 protocol (53%-62% higher DE contrast than in the 140/80 kV protocol without additional filtration). The DE ratios and DE contrasts of the 80/140 kV and 100/Sn140 kV protocols were comparable. Uric acid, cystine and calcified calculi could be reliably differentiated by any of the protocols. A dose-neutral gain of DE contrast was found in the Sn-filter protocols, which might improve the differentiation of smaller calculi (Sn140/80 kV) and improve image quality and calculi differentiation in larger patients (Sn140/100 kV). However, even with the improved spectral separation of the Sn-filter protocols, the DE ratios of calcified calculi are not sufficiently distinct to allow a differentiation within this group.
    Investigative radiology 07/2010; 45(7):393-8. · 4.85 Impact Factor
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    ABSTRACT: Brown adipose tissue (BAT) regulates energy homeostasis and fat mass in mammals and newborns and, most likely, in adult humans. Because BAT activity and BAT mass decline with age in humans, the impact of BAT on adiposity may decrease with aging. In the present study we addressed this hypothesis and further investigated the effect of age on the sex differences in BAT activity and BAT mass. Data from 260 subjects (98 with BAT and 162 study date-matched control subjects) who underwent (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) under thermoneutral conditions were analyzed. BAT activity and BAT mass were determined in the upper body. BAT activity and BAT mass were higher in female (1.59 +/- 0.10 and 32 +/- 5 g vs. 1.02 +/- 0.10 and 18 +/- 4 g, both P < or = 0.0006) than in male subjects. In multivariate analyses, sex (P < 0.0001), age (P < 0.0001), and BMI (P = 0.0018) were associated independently with BAT activity. Interestingly, only in male subjects was there an interaction between BMI and age in determining BAT activity (P = 0.008) and BAT mass (P = 0.0002); BMI decreased with increasing BAT activity and BAT mass in the lowest age tertile (Spearman rank correlation coefficient r(s) = -0.38, P = 0.015 and r(s) = -0.37, P = 0.017, respectively), not in the higher age tertiles. Furthermore, BAT activity and mass differed between female and male subjects only in the upper two age tertiles (all P < or = 0.09). Our data corroborate that, in general, BAT activity and BAT mass are elevated in female subjects and in younger people. Importantly, we provide novel evidence that the impact of BAT activity and BAT mass on adiposity appears to decline with aging only in male subjects. Furthermore, while BAT activity and BAT mass only moderately decline with increasing age in female subjects, a much stronger effect is found in male subjects.
    Diabetes 03/2010; 59(7):1789-93. · 7.90 Impact Factor
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • European Journal of Nuclear Medicine 12/2009; 37(2):407-8. · 4.53 Impact Factor
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    ABSTRACT: The aim of the study was to assess variations in the diameter of the common bile duct in patients with gastrointestinal graft-versus-host disease (GVHD) undergoing abdominal CT after allogeneic hematopoietic stem cell transplantation and to correlate the findings with laboratory results on cholestasis. We performed a retrospective analysis of the caliber of the common bile duct in 27 adult patients with histologically validated gastrointestinal GVHD who underwent two or more follow-up abdominal CT examinations. Another 25 patients who underwent allogeneic hematopoietic stem cell transplantation during the same period at our institution but who did not have GVHD constituted the control group. The diameters of the common bile duct were correlated with cholestasis values. A pathologic diameter of the common bile duct was defined as greater than 7 mm (48 patients) in patients who had not undergone cholecystectomy and greater than 8 mm in those who had (four patients). The median diameter of the common bile duct was 7 mm (range, 4-14.8 mm) in the GVHD group and 5.8 mm (range, 3.9-10.2 mm) in the control group. Pathologic diameters of the common bile duct were found in 67% of the patients in the GVHD group and in 12% of the control group (p < 0.0001). The variation coefficient of the diameter of the common bile duct was 12.4% in the GVHD group (83 examinations) and 6.4% in the control group (92 examinations) (p < 0.0001). Ninety-six percent of the patients in the GVHD group had elevated cholestasis values with a significant positive correlation between bilirubin concentration and diameter of the common bile duct (r = 0.421; p = 0.032). Enhancement of the common bile duct and gallbladder wall was seen in the majority of GVHD patients but no controls (p < 0.0001). Temporary dilatation of the common bile duct seems to be a common finding in gastrointestinal GVHD after hematopoietic stem cell transplantation and correlates with bilirubin concentration. This knowledge of fluctuation in bile duct diameter can help to avoid unnecessary tests to evaluate for pathologic causes of biliary dilatation.
    American Journal of Roentgenology 09/2009; 193(3):W181-5. · 2.90 Impact Factor
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    ABSTRACT: Granulocytic sarcomas (GS) are rare extramedullary manifestations of myeloid or lymphoblastic leukaemia. Laboratory examinations are of limited use for diagnosis of extramedullary disease. Radiological imaging based on morphology is challenging. To date, the possible role of FDG-PET/CT as a method for combined metabolic and morphologic imaging is unclear. We present a series of 10 patients to evaluate the potential role of FDG-PET/CT in the management of GS. PATIENTS, MATERIALS, METHODS: A retrospective evaluation of 18 FDG-PET/CT exams in 10 patients with histologically proven GS was performed. All scans included a contrast enhanced CT. The FDG uptake of GS was analyzed and the sensitivity of lesion detection was compared to PET and CT alone. The changes in FDG uptake after therapy were compared to morphological changes detected by CT and follow-up / clinical outcome. 52 untreated or recurrent GS lesions were detected by FDG-PET/CT and all showed an increased FDG uptake with a mean SUVmax and SUVavg of 5.1 and 3.4, respectively. GS was multifocal in 8/10 patients. Combined PET/CT avoided 5 false positive findings compared to PET alone and 13 false negative findings and 1 false positive compared to CT alone. Changes in FDG uptake after therapy correlated with clinical outcome and were more reliable than CT assessment alone. PET/CT identified recurrent GS in 3 patients. Viable GS are FDG-avid. Using this metabolic information and morphologic CT criteria, combined FDG-PET/CT was more accurate in lesion detection than FDG-PET or CT alone. Changes in FDG uptake after therapy might be a useful additional parameter for therapy monitoring. Therefore, FDG-PET/CT appears to be a promising diagnostic and monitoring tool in the management of patients with GS.
    Nuklearmedizin 09/2009; 48(5):185-91. · 1.32 Impact Factor

Publication Stats

177 Citations
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62.65 Total Impact Points

Institutions

  • 2008–2013
    • Universitätsklinikum Tübingen
      • • Department of Radiology
      • • Division of Diagnostic and Interventional Radiology
      Tübingen, Baden-Württemberg, Germany
    • University of Tuebingen
      • Department of Internal Medicine
      Tübingen, Baden-Württemberg, Germany