@article{BeyhoffLohrThieleetal.2020,
  author    = {Beyhoff, Niklas and Lohr, David and Thiele, Arne and Foryst-Ludwig, Anna and Klopfleisch, Robert and Schreiber, Laura M. and Kintscher, Ulrich},
  title     = {Myocardial Infarction After High-Dose Catecholamine Application—A Case Report From an Experimental Imaging Study},
  series = {Frontiers in Cardiovascular Medicine},
  volume    = {7},
  journal   = {Frontiers in Cardiovascular Medicine},
  doi       = {10.3389/fcvm.2020.580296},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217959},
  year      = {2020},
  abstract  = {Although heart failure following myocardial infarction (MI) represents a major health burden, underlying microstructural and functional changes remain incompletely understood. Here, we report on a case of unexpected MI after treatment with the catecholamine isoproterenol in an experimental imaging study in mice using different state-of-the-art imaging modalities. The decline in cardiac function was documented by ultrahigh-frequency echocardiography and speckle-tracking analyses. Myocardial microstructure was studied ex vivo at a spatial resolution of 100 × 100 × 100 μm\(^{3}\) using diffusion tensor magnetic resonance imaging (DT-MRI) and histopathologic analyses. Two weeks after ISO treatment, the animal showed an apical aneurysm accompanied by reduced radial strain in corresponding segments and impaired global systolic function. DT-MRI revealed a loss of contractile fiber tracts together with a disarray of remaining fibers as corresponding microstructural correlates. This preclinical case report provides valuable insights into pathophysiology and morphologic-functional relations of heart failure following MI using emerging imaging technologies.},
  language  = {en}
}
@article{MartensPanzervandenWijngaardetal.2020,
  author    = {Martens, Johannes and Panzer, Sabine and van den Wijngaard, Jeroen and Siebes, Maria and Schreiber, Laura M.},
  title     = {Influence of contrast agent dispersion on bolus-based MRI myocardial perfusion measurements: A computational fluid dynamics study},
  series = {Magnetic Resonance in Medicine},
  volume    = {84},
  journal   = {Magnetic Resonance in Medicine},
  number    = {1},
  doi       = {10.1002/mrm.28125},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208698},
  pages     = {467-483},
  year      = {2020},
  abstract  = {Purpose: Bolus-based dynamic contrast agent (CA) perfusion measurements of the heart are subject to systematic errors due to CA bolus dispersion in the coronary arteries. To better understand these effects on quantification of myocardial blood flow and myocardial perfusion reserve (MPR), an in-silico model of the coronary arteries down to the pre-arteriolar vessels has been developed. Methods: In this work, a computational fluid dynamics analysis is performed to investigate these errors on the basis of realistic 3D models of the left and right porcine coronary artery trees, including vessels at the pre-arteriolar level. Using advanced boundary conditions, simulations of blood flow and CA transport are conducted at rest and under stress. These are evaluated with regard to dispersion (assessed by the width of CA concentration time curves and associated vascular transport functions) and errors of myocardial blood flow and myocardial perfusion reserve quantification. Results: Contrast agent dispersion increases with traveled distance as well as vessel diameter, and decreases with higher flow velocities. Overall, the average myocardial blood flow errors are -28\% ± 16\% and -8.5\% ± 3.3\% at rest and stress, respectively, and the average myocardial perfusion reserve error is 26\% ± 22\%. The calculated values are different in the left and right coronary tree. Conclusion: Contrast agent dispersion is dependent on a complex interplay of several different factors characterizing the cardiovascular bed, including vessel size and integrated vascular length. Quantification errors evoked by the observed CA dispersion show nonnegligible distortion in dynamic CA bolus-based perfusion measurements. We expect future improvements of quantitative perfusion measurements to make the systematic errors described here more apparent.},
  language  = {en}
}
@article{ElabyadTerekhovLohretal.2020,
  author    = {Elabyad, Ibrahim A. and Terekhov, Maxim and Lohr, David and Stefanescu, Maria R. and Baltes, Steffen and Schreiber, Laura M.},
  title     = {A Novel Mono-surface Antisymmetric 8Tx/16Rx Coil Array for Parallel Transmit Cardiac MRI in Pigs at 7T},
  series = {Scientific Reports},
  volume    = {10},
  journal   = {Scientific Reports},
  number    = {1},
  doi       = {10.1038/s41598-020-59949-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229436},
  year      = {2020},
  abstract  = {A novel mono-surface antisymmetric 16-element transmit/receive (Tx/Rx) coil array was designed, simulated, constructed, and tested for cardiac magnetic resonance imaging (cMRI) in pigs at 7T. The cardiac array comprised of a mono-surface 16-loops with two central elements arranged antisymmetrically and flanked by seven elements on either side. The array was configured for parallel transmit (pTx) mode to have an eight channel transmit and 16-channel receive (8Tx/16Rx) coil array. Electromagnetic (EM) simulations, bench-top measurements, phantom, and MRI experiments with two pig cadavers (68 and 46 kg) were performed. Finally, the coil was used in pilot in-vivo measurements with a 60 kg pig. Flip angle (FA), geometry factor (g-factor), signal-to-noise ratio (SNR) maps, and high-resolution cardiac images were acquired with an in-plane resolution of 0.6 mm x 0.6 mm (in-vivo) and 0.3 mm x 0.3 mm (ex-vivo). The mean g-factor over the heart was 1.26 (R = 6). Static phase B-1(+) shimming in a pig body phantom with the optimal phase vectors makes possible to improve the B-1(+) homogeneity by factor > 2 and transmit efficiency by factor > 3 compared to zero phases (before RF shimming). Parallel imaging performed in the in-vivo measurements demonstrated well preserved diagnostic quality of the resulting images at acceleration factors up to R = 6. The described hardware design can be adapted for arrays optimized for animals and humans with a larger number of elements (32-64) while maintaining good decoupling for various MRI applications at UHF (e.g., cardiac, head, and spine).},
  language  = {en}
}