@article{RufBeerKoestleretal.2019, author = {Ruf, Katharina and Beer, Meinrad and K{\"o}stler, Herbert and Weng, Andreas Max and Neubauer, Henning and Klein, Alexander and Platek, Kathleen and Roth, Kristina and Beneke, Ralph and Hebestreit, Helge}, title = {Size-adjusted muscle power and muscle metabolism in patients with cystic fibrosis are equal to healthy controls - a case control study}, series = {BMC Pulmonary Medicine}, volume = {19}, journal = {BMC Pulmonary Medicine}, doi = {10.1186/s12890-019-1039-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200981}, pages = {269}, year = {2019}, abstract = {Background Skeletal muscle function dysfunction has been reported in patients with cystic fibrosis (CF). Studies so far showed inconclusive data whether reduced exercise capacity is related to intrinsic muscle dysfunction in CF. Methods Twenty patients with CF and 23 age-matched controls completed an incremental cardiopulmonary cycling test. Further, a Wingate anaerobic test to assess muscle power was performed. In addition, all participants completed an incremental knee-extension test with 31P magnetic resonance spectroscopy to assess muscle metabolism (inorganic phosphate (Pi) and phosphocreatinine (PCr) as well as intracellular pH). In the MRI, muscle cross-sectional area of the M. quadriceps (qCSA) was also measured. A subgroup of 15 participants (5 CF, 10 control) additionally completed a continuous high-intensity, high-frequency knee-extension exercise task during 31P magnetic resonance spectroscopy to assess muscle metabolism. Results Patients with CF showed a reduced exercise capacity in the incremental cardiopulmonary cycling test (VO2peak: CF 77.8 ± 16.2\%predicted (36.5 ± 7.4 ml/qCSA/min), control 100.6 ± 18.8\%predicted (49.1 ± 11.4 ml/qCSA/min); p < 0.001), and deficits in anaerobic capacity reflected by the Wingate test (peak power: CF 537 ± 180 W, control 727 ± 186 W; mean power: CF 378 ± 127 W, control 486 ± 126 W; power drop CF 12 ± 5 W, control 8 ± 4 W. all: p < 0.001). In the knee-extension task, patients with CF achieved a significantly lower workload (p < 0.05). However, in a linear model analysing maximal work load of the incremental knee-extension task and results of the Wingate test, respectively, only muscle size and height, but not disease status (CF or not) contributed to explaining variance. In line with this finding, no differences were found in muscle metabolism reflected by intracellular pH and the ratio of Pi/PCr at submaximal stages and peak exercise measured through MRI spectroscopy. Conclusions The lower absolute muscle power in patients with CF compared to controls is exclusively explained by the reduced muscle size in this study. No evidence was found for an intrinsic skeletal muscle dysfunction due to primary alterations of muscle metabolism.}, language = {en} } @article{PetritschKosmalaWengetal.2019, author = {Petritsch, Berhard and Kosmala, Aleksander and Weng, Andreas Max and Bley, Thorsten Alexander}, title = {Tin-filtered 100kV ultra-low-dose CT of the paranasal sinus: initial clinical results}, series = {PLoS ONE}, volume = {14}, journal = {PLoS ONE}, number = {5}, doi = {10.1371/ journal.pone.0216295}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204127}, pages = {e0216295}, year = {2019}, abstract = {Objectives To investigate the feasibility, diagnostic image quality and radiation dose of 3\(^{rd}\) generation dual-source computed tomography (CT) using a tin-filtered 100 kV protocol in patients with suspected acute inflammatory sinus disease. Methods We retrospectively evaluated 109 consecutive patients who underwent CT (Siemens SOMATOM Force, Erlangen, Germany) of the paranasal sinus with a new tin-filtered scanprotocol (Sn100 kV; tube current 35 mAs) using iterative reconstruction. Two readers independently assessed subjective image quality using a five-point Likert scale (1 = excellent, 5 = non-diagnostic). Inter-observer agreement was calculated and expressed as percentage of agreement. Noise was determined for calculation of signal-to-noise-ratio (SNR). Effective radiation dose (ED) was calculated from the dose-length-product (DLP). Results All examinations showed diagnostic image quality regarding evaluation of inflammatory sinus disease. On average, subjective general image quality was rated moderate (= 3) with a percentage of agreement between the observers of 81\%. The mean image noise was 14.3 HU. The calculated median SNR was 6.0 for intraorbital fat, and 3.6 for the vitreous body, respectively. The median DLP was 2.1 mGy*cm, resulting in a median ED of 0.012 mSv. Conclusions Taking the study limitations into account, ultra-low-dose tin-filtered CT of the paranasal sinus at a tube voltage of 100 kV utilizing an iterative reconstruction algorithm provides for reliable exclusion of suspected acute inflammatory sinus disease in 100\% of the cases.}, language = {en} } @article{LohrTerekhovWengetal.2019, author = {Lohr, David and Terekhov, Maxim and Weng, Andreas Max and Schroeder, Anja and Walles, Heike and Schreiber, Laura Maria}, title = {Spin echo based cardiac diffusion imaging at 7T: An ex vivo study of the porcine heart at 7T and 3T}, series = {PLoS ONE}, volume = {14}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0213994}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201376}, pages = {e0213994}, year = {2019}, abstract = {Purpose of this work was to assess feasibility of cardiac diffusion tensor imaging (cDTI) at 7 T in a set of healthy, unfixed, porcine hearts using various parallel imaging acceleration factors and to compare SNR and derived cDTI metrics to a reference measured at 3 T. Magnetic resonance imaging was performed on 7T and 3T whole body systems using a spin echo diffusion encoding sequence with echo planar imaging readout. Five reference (b = 0 s/mm\(^2\)) images and 30 diffusion directions (b = 700 s/mm\(^2\)) were acquired at both 7 T and 3 T using a GRAPPA acceleration factor R = 1. Scans at 7 T were repeated using R = 2, R = 3, and R = 4. SNR evaluation was based on 30 reference (b = 0 s/mm\(^2\)) images of 30 slices of the left ventricle and cardiac DTI metrics were compared within AHA segmentation. The number of hearts scanned at 7 T and 3 T was n = 11. No statistically significant differences were found for evaluated helix angle, secondary eigenvector angle, fractional anisotropy and apparent diffusion coefficient at the different field strengths, given sufficiently high SNR and geometrically undistorted images. R≥3 was needed to reduce susceptibility induced geometric distortions to an acceptable amount. On average SNR in myocardium of the left ventricle was increased from 29±3 to 44±6 in the reference image (b = 0 s/mm\(^2\)) when switching from 3 T to 7 T. Our study demonstrates that high resolution, ex vivo cDTI is feasible at 7 T using commercial hardware.}, language = {en} } @article{KosmalaGruschwitzVeldhoenetal.2020, author = {Kosmala, Aleksander and Gruschwitz, Philipp and Veldhoen, Simon and Weng, Andreas Max and Krauss, Bernhard and Bley, Thorsten Alexander and Petritsch, Bernhard}, title = {Dual-energy CT angiography in suspected pulmonary embolism: influence of injection protocols on image quality and perfused blood volume}, series = {The International Journal of Cardiovascular Imaging}, volume = {36}, journal = {The International Journal of Cardiovascular Imaging}, number = {10}, issn = {1569-5794}, doi = {10.1007/s10554-020-01911-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-314739}, pages = {2051-2059}, year = {2020}, abstract = {Abstract To compare intravenous contrast material (CM) injection protocols for dual-energy CT pulmonary angiography (CTPA) in patients with suspected acute pulmonary embolism with regard to image quality and pulmonary perfused blood volume (PBV) values. A total of 198 studies performed with four CM injection protocols varying in CM volume and iodine delivery rates (IDR) were retrospectively included: (A) 60 ml at 5 ml/s (IDR = 1.75gI/s), (B) 50 ml at 5 ml/s (IDR = 1.75gI/s), (C) 50 ml at 4 ml/s (IDR = 1.40gI/s), (D) 40 ml at 3 ml/s (IDR = 1.05gI/s). Image quality and PBV values at different resolution settings were compared. Pulmonary arterial tract attenuation was highest for protocol A (397 ± 110 HU; p vs. B = 0.13; vs. C = 0.02; vs. D < 0.001). CTPA image quality of protocol A was rated superior compared to protocols B and D by reader 1 (p = 0.01; < 0.001), and superior to protocols B, C and D by reader 2 (p < 0.001; 0.02; < 0.001). Otherwise, there were no significant differences in CTPA quality ratings. Subjective iodine map ratings did not vary significantly between protocols A, B, and C. Both readers rated protocol D inferior to all other protocols (p < 0.05). PBV values did not vary significantly between protocols A and B at resolution settings of 1, 4 and 10 (p = 0.10; 0.10; 0.09), while otherwise PBV values displayed a decreasing trend from protocol A to D (p < 0.05). Higher CM volume and IDR are associated with superior CTPA and iodine map quality and higher absolute PBV values.}, language = {en} } @misc{KosmalaGruschwitzVeldhoenetal.2022, author = {Kosmala, Aleksander and Gruschwitz, Philipp and Veldhoen, Simon and Weng, Andreas Max and Krauss, Bernhard and Bley, Thorsten Alexander and Petritsch, Bernhard}, title = {Correction to: Dual-energy CT angiography in suspected pulmonary embolism: infuence of injection protocols on image quality and perfused blood volume}, series = {The International Journal of Cardiovascular Imaging}, volume = {38}, journal = {The International Journal of Cardiovascular Imaging}, number = {3}, doi = {10.1007/s10554-021-02439-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350830}, pages = {707}, year = {2022}, abstract = {No abstract available.}, language = {en} } @article{GilbertKleinWengetal.2017, author = {Gilbert, Fabian and Klein, Detlef and Weng, Andreas Max and K{\"o}stler, Herbert and Schmitz, Benedikt and Schmalzl, Jonas and B{\"o}hm, Dirk}, title = {Supraspinatus muscle elasticity measured with real time shear wave ultrasound elastography correlates with MRI spectroscopic measured amount of fatty degeneration}, series = {BMC Muscoskeletal Disorders}, volume = {18}, journal = {BMC Muscoskeletal Disorders}, number = {549}, doi = {10.1186/s12891-017-1911-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159378}, year = {2017}, abstract = {Background: Fatty Degeneration (FD) of the rotator cuff muscles influences functional and anatomical outcome after rotator cuff repair. The MRI based estimation of fatty degeneration is the gold standard. There is some evidence that Ultrasound elastography (EUS) can detect local differences of tissue stiffness in muscles and tendons. Shear-wave elastography (SWE) was evaluated to determine the extent to which shear wave velocity was associated with measures of fatty degeneration. MRI-spectroscopic fat measurement was used as a reference to quantify the amount of fat in the muscle belly. Methods: Forty-two patients underwent SWE of the supraspinatus muscles at its thickest diameter. After ultrasound evaluation an MRI-spectroscopic fat measurement of the supraspinatus muscle was performed using the SPLASH-technique. A gel filled capsule was used to locate the measured area in the MRI. The values of shear wave velocity (SWV) measured with SWE and spectroscopic fat measurement were correlated statistically using Pearson's correlation test. Results: Correlation of the fat amount measured with MRI-spectroscopy and the SWV measured with SWE was ρ =0.82. Spectroscopic measured fat ratio of the supraspinatus muscle ranged from 0\% to 77.41\% and SWV from 1.59 m/s to 5.32 m/s. In 4 patients no sufficient SWE could be performed, these individuals showed a larger diameter of the overlying soft tissue. SWV measured with SWE showed a good correlation with MRI spectroscopic fat amount of the supraspinatus muscle. Conclusion: These preliminary data suggest that SWE may be a sufficient tool in detecting and estimating the amount of fatty degeneration in the supraspinatus muscle in real time. Large overlying soft tissue may be a limitation in performing sufficient EUS.}, language = {en} }