@article{ReiterRitterPrinceetal.2012,
  author    = {Reiter, Theresa and Ritter, Oliver and Prince, Martin R. and Nordbeck, Peter and Wanner, Christoph and Nagel, Eike and Bauer, Wolfgang R.},
  title     = {Minimizing Risk of Nephrogenic systemic fibrosis in Cardiovascular Magnetic Resonance},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75068},
  year      = {2012},
  abstract  = {Nephrogenic Systemic Fibrosis is a rare condition appearing only in patients with severe renal impairment or failure and presents with dermal lesions and involvement of internal organs. Although many cases are mild, an estimated 5 \% have a progressive debilitating course. To date, there is no known effective treatment thus stressing the necessity of ample prevention measures. An association with the use of Gadolinium based contrast agents (GBCA) makes Nephrogenic Systemic Fibrosis a potential side effect of contrast enhanced magnetic resonance imaging and offers the opportunity for prevention by limiting use of gadolinium based contrast agents in renal failure patients. In itself toxic, Gadolinium is embedded into chelates that allow its safe use as a contrast agent. One NSF theory is that Gadolinium chelates distribute into the extracellular fluid compartment and set Gadolinium ions free, depending on multiple factors among which the duration of chelates exposure is directly related to the renal function. Major medical societies both in Europe and in North America have developed guidelines for the usage of GBCA. Since the establishment of these guidelines and the increased general awareness of this condition, the occurrence of NSF has been nearly eliminated. Giving an overview over the current knowledge of NSF pathobiochemistry, pathogenesis and treatment options this review focuses on the guidelines of the European Medicines Agency, the European Society of Urogenital Radiology, the FDA and the American College of Radiology from 2008 up to 2011 and the transfer of this knowledge into every day practice.},
  subject      = {CMR},
  language  = {en}
}
@article{ReiterRitterNordbecketal.2012,
  author    = {Reiter, Theresa and Ritter, Oliver and Nordbeck, Peter and Beer, Meinrad and Bauer, Wolfgang Rudolf},
  title     = {MRI-guided ablation of wide complex tachycardia in a univentricular heart},
  series = {World Journal of Cardiology},
  volume    = {4},
  journal   = {World Journal of Cardiology},
  number    = {8},
  doi       = {10.4330/wjc.v4.i8.260},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123165},
  pages     = {260-263},
  year      = {2012},
  abstract  = {Magnetic resonance imaging can be used for preprocedural assessment of complex anatomy for radiofrequency (RF) ablations, e.g., in a univentricular heart. This case report features the treatment of a young patient with a functionally univentricular heart who suffered from persistent sudden onset tachycardia with wide complexes that required RF ablation as treatment.},
  language  = {en}
}
@article{ReiterGenslerRitteretal.2012,
  author    = {Reiter, Theresa and Gensler, Daniel and Ritter, Oliver and Weiss, Ingo and Geistert, Wolfgang and Kaufmann, Ralf and Hoffmeister, Sabine and Friedrich, Michael T. and Wintzheimer, Stefan and D{\"u}ring, Markus and Nordbeck, Peter and Jakob, Peter M. and Ladd, Mark E. and Quick, Harald H. and Bauer, Wolfgang R.},
  title     = {Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures},
  series = {Journal of Cardiovascular Magnetic Resonance},
  volume    = {14},
  journal   = {Journal of Cardiovascular Magnetic Resonance},
  number    = {12},
  doi       = {10.1186/1532-429X-14-12},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134927},
  year      = {2012},
  abstract  = {Background: One of the safety concerns when performing electrophysiological (EP) procedures under magnetic resonance (MR) guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF) field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating. Methods: A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany) using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany). The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA) at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip. Results: A maximum temperature rise of 22.4 degrees C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N). The catheter tip irrigation was able to limit the temperature rise to less than 2 degrees C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8 degrees C. Conclusion: Up to a maximum of 22.4 degrees C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation system. The irrigated tip system can be used to increase MR safety of EP catheters by suppressing the effects of unwanted passive catheter heating due to RF exposure from the MR scanner.},
  language  = {en}
}
@article{LapaReiterKircheretal.2016,
  author    = {Lapa, Constantin and Reiter, Theresa and Kircher, Malte and Schirbel, Andreas and Werner, Rudolf A. and Pelzer, Theo and Pizarro, Carmen and Skowasch, Dirk and Thomas, Lena and Schlesinger-Irsch, Ulrike and Thomas, Daniel and Bundschuh, Ralph A. and Bauer, Wolfgang R. and Gartner, Florian C.},
  title     = {Somatostatin receptor based PET/CT in patients with the suspicion of cardiac sarcoidosis: an initial comparison to cardiac MRI},
  series = {Oncotarget},
  volume    = {7},
  journal   = {Oncotarget},
  number    = {47},
  doi       = {10.18632/oncotarget.12799},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175423},
  pages     = {77807-77814},
  year      = {2016},
  abstract  = {Diagnosis of cardiac sarcoidosis is often challenging. Whereas cardiac magnetic resonance imaging (CMR) and positron emission tomography/computed tomography (PET/CT) with \(^{18}\)F-fluorodeoxyglucose (FDG) are most commonly used to evaluate patients, PET/CT using radiolabeled somatostatin receptor (SSTR) ligands for visualization of inflammation might represent a more specific alternative. This study aimed to investigate the feasibility of SSTR-PET/CT for detecting cardiac sarcoidosis in comparison to CMR. 15 patients (6 males, 9 females) with sarcoidosis and suspicion on cardiac involvement underwent SSTR-PET/CT imaging and CMR. Images were visually scored. The AHA 17-segment model of the left myocardium was used for localization and comparison of inflamed myocardium for both imaging modalities. In semi-quantitative analysis, mean (SUV\(_{mean}\)) and maximum standardized uptake values (SUV\(_{max}\)) of affected myocardium were calculated and compared with both remote myocardium and left ventricular (LV) cavity. SSTR-PET was positive in 7/15, CMR in 10/15 patients. Of the 3 CMR+/PET- subjects, one patient with minor involvement (<25\% of wall thickness in CMR) was missed by PET. The remaining two CMR+/PET- patients displayed no adverse cardiac events during follow-up. In the 17-segment model, PET/CT yielded 27 and CMR 29 positive segments. Overall concordance of the 2 modalities was 96.1\% (245/255 segments analyzed). SUV\(_{mean}\) and SUV\(_{max}\) in inflamed areas were 2.0±1.2 and 2.6±1.2, respectively. The lesion-to-remote myocardium and lesion-to-LV cavity ratios were 1.8±0.2 and 1.9±0.2 for SUV\(_{mean}\) and 2.0±0.3 and 1.7±0.3 for SUV\(_{max}\), respectively. Detection of cardiac sarcoidosis by SSTR-PET/CT is feasible. Our data warrant further analysis in larger prospective series.},
  language  = {en}
}
@article{KampfBauerReiter2018,
  author    = {Kampf, Thomas and Bauer, Wolfgang Rudolf and Reiter, Theresa},
  title     = {Improved post-processing strategy for MOLLI based tissue characterization allows application in patients with dyspnoe and impaired left ventricular function},
  series = {Zeitschrift f{\"u}r Medizinische Physik},
  volume    = {28},
  journal   = {Zeitschrift f{\"u}r Medizinische Physik},
  doi       = {10.1016/j.zemedi.2017.07.003},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325481},
  pages     = {25-35},
  year      = {2018},
  abstract  = {Contrast and non-contrast MRI based characterization of myocardium by T1-mapping will be of paramount importance to obtain biomarkers, e.g. fibrosis, which determines the risk of heart failure patients. T1-mapping by the standard post-processing of the modified look-locker inversion recovery (MOLLI) lacks of accuracy when trying to reduce its duration, which on the other hand, is highly desirable in patients with heart failure. The recently suggested inversion group fitting (IGF) technique, which considers more parameters for fitting, has a superior accuracy for long T1 times despite a shorter duration. However, for short T1 values, the standard method has a superior precision. A conditional fitting routine is proposed which ideally takes advantage of both algorithms. Materials and methods All measurements were performed on a 1.5 T clinical scanner (ACHIEVA, Philips Healthcare, The Netherlands) using a MOLLI 5(n)3(n)3 prototype with n(heart beats) being a variable waiting time between inversion experiments. Phantom experiments covered a broad range of T1 times, waiting times and heart rates. A saturation recovery experiment served as a gold standard for T1 measurement. All data were analyzed with the standard MOLLI, the IGF fit and the conditional fitting routine and the obtained T1 values were compared with the gold standard. In vivo measurements were performed in a healthy volunteer and a total of 34 patients with normal findings, dilative cardiomyopathy and amyloidosis. Results Theoretical analysis and phantom experiments provided a threshold value for an apparent IGF determining processing with IGF post processing for values above, or switching to the standard technique for values below. This was validated in phantoms and patients measurements. A reduction of the waiting time to 1 instead of 3 heart beats between the inversion experiments showed reliable results. The acquisition time was reduced from 17 to 13 heart beats. The in vivo measurements showed ECV values between 25\% (18-33\%; SD 0.03) in the healthy, 30\% (22-40\%; SD 0.04) in patients with DCM and 45\% (30-60\%; SD 0.9) in patients with amyloidosis. Conclusion The adopted post-processing algorithm determines long T1 values with high accuracy and short T1 values while maintaining a high precision. Based on reduction of waiting time, and independence of heart rate, it shortens breath hold duration and allows fast T1-mapping, which is frequently a prerequisite in patients with cardiac diseases.},
  language  = {en}
}
@article{KampfReiterBauer2018,
  author    = {Kampf, Thomas and Reiter, Theresa and Bauer, Wolfgang Rudolf},
  title     = {An analytical model which determines the apparent T1 for Modified Look-Locker Inversion Recovery - Analysis of the longitudinal relaxation under the influence of discontinuous balanced (classical MOLLI) and spoiled gradient echo readouts},
  series = {Zeitschrift f{\"u}r Medizinische Physik},
  volume    = {28},
  journal   = {Zeitschrift f{\"u}r Medizinische Physik},
  doi       = {10.1016/j.zemedi.2017.07.004},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325498},
  pages     = {150-157},
  year      = {2018},
  abstract  = {Quantitative nuclear magnetic resonance imaging (MRI) shifts more and more into the focus of clinical research. Especially determination of relaxation times without/and with contrast agents becomes the foundation of tissue characterization, e.g. in cardiac MRI for myocardial fibrosis. Techniques which assess longitudinal relaxation times rely on repetitive application of readout modules, which are interrupted by free relaxation periods, e.g. the Modified Look-Locker Inversion Recovery = MOLLI sequence. These discontinuous sequences reveal an apparent relaxation time, and, by techniques extrapolated from continuous readout sequences, a putative real T1 is determined. What is missing is a rigorous analysis of the dependence of the apparent relaxation time on its real partner, readout sequence parameters and biological parameters as heart rate. This is provided in this paper for the discontinuous balanced steady state free precession (bSSFP) and spoiled gradient echo readouts. It turns out that the apparent longitudinal relaxation rate is the time average of the relaxation rates during the readout module, and free relaxation period. Knowing the heart rate our results vice versa allow to determine the real T1 from its measured apparent partner.},
  language  = {en}
}
@article{AnkenbrandLohrSchloetelburgetal.2021,
  author    = {Ankenbrand, Markus Johannes and Lohr, David and Schl{\"o}telburg, Wiebke and Reiter, Theresa and Wech, Tobias and Schreiber, Laura Maria},
  title     = {Deep learning-based cardiac cine segmentation: Transfer learning application to 7T ultrahigh-field MRI},
  series = {Magnetic Resonance in Medicine},
  volume    = {86},
  journal   = {Magnetic Resonance in Medicine},
  number    = {4},
  doi       = {10.1002/mrm.28822},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257604},
  pages     = {2179-2191},
  year      = {2021},
  abstract  = {Purpose Artificial neural networks show promising performance in automatic segmentation of cardiac MRI. However, training requires large amounts of annotated data and generalization to different vendors, field strengths, sequence parameters, and pathologies is limited. Transfer learning addresses this challenge, but specific recommendations regarding type and amount of data required is lacking. In this study, we assess data requirements for transfer learning to experimental cardiac MRI at 7T where the segmentation task can be challenging. In addition, we provide guidelines, tools, and annotated data to enable transfer learning approaches by other researchers and clinicians. Methods A publicly available segmentation model was used to annotate a publicly available data set. This labeled data set was subsequently used to train a neural network for segmentation of left ventricle and myocardium in cardiac cine MRI. The network is used as starting point for transfer learning to 7T cine data of healthy volunteers (n = 22; 7873 images) by updating the pre-trained weights. Structured and random data subsets of different sizes were used to systematically assess data requirements for successful transfer learning. Results Inconsistencies in the publically available data set were corrected, labels created, and a neural network trained. On 7T cardiac cine images the model pre-trained on public imaging data, acquired at 1.5T and 3T, achieved DICE\(_{LV}\) = 0.835 and DICE\(_{MY}\) = 0.670. Transfer learning using 7T cine data and ImageNet weight initialization improved model performance to DICE\(_{LV}\) = 0.900 and DICE\(_{MY}\) = 0.791. Using only end-systolic and end-diastolic images reduced training data by 90\%, with no negative impact on segmentation performance (DICE\(_{LV}\) = 0.908, DICE\(_{MY}\) = 0.805). Conclusions This work demonstrates and quantifies the benefits of transfer learning for cardiac cine image segmentation. We provide practical guidelines for researchers planning transfer learning projects in cardiac MRI and make data, models, and code publicly available.},
  language  = {en}
}
@article{HockTerekhovStefanescuetal.2021,
  author    = {Hock, Michael and Terekhov, Maxim and Stefanescu, Maria Roxana and Lohr, David and Herz, Stefan and Reiter, Theresa and Ankenbrand, Markus and Kosmala, Aleksander and Gassenmaier, Tobias and Juchem, Christoph and Schreiber, Laura Maria},
  title     = {B\(_{0}\) shimming of the human heart at 7T},
  series = {Magnetic Resonance in Medicine},
  volume    = {85},
  journal   = {Magnetic Resonance in Medicine},
  number    = {1},
  doi       = {10.1002/mrm.28423},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218096},
  pages     = {182 -- 196},
  year      = {2021},
  abstract  = {Purpose Inhomogeneities of the static magnetic B\(_{0}\) field are a major limiting factor in cardiac MRI at ultrahigh field (≥ 7T), as they result in signal loss and image distortions. Different magnetic susceptibilities of the myocardium and surrounding tissue in combination with cardiac motion lead to strong spatio-temporal B\(_{0}\)-field inhomogeneities, and their homogenization (B0 shimming) is a prerequisite. Limitations of state-of-the-art shimming are described, regional B\(_{0}\) variations are measured, and a methodology for spherical harmonics shimming of the B\(_{0}\) field within the human myocardium is proposed. Methods The spatial B\(_{0}\)-field distribution in the heart was analyzed as well as temporal B\(_{0}\)-field variations in the myocardium over the cardiac cycle. Different shim region-of-interest selections were compared, and hardware limitations of spherical harmonics B\(_{0}\) shimming were evaluated by calibration-based B0-field modeling. The role of third-order spherical harmonics terms was analyzed as well as potential benefits from cardiac phase-specific shimming. Results The strongest B\(_{0}\)-field inhomogeneities were observed in localized spots within the left-ventricular and right-ventricular myocardium and varied between systolic and diastolic cardiac phases. An anatomy-driven shim region-of-interest selection allowed for improved B\(_{0}\)-field homogeneity compared with a standard shim region-of-interest cuboid. Third-order spherical harmonics terms were demonstrated to be beneficial for shimming of these myocardial B\(_{0}\)-field inhomogeneities. Initial results from the in vivo implementation of a potential shim strategy were obtained. Simulated cardiac phase-specific shimming was performed, and a shim term-by-term analysis revealed periodic variations of required currents. Conclusion Challenges in state-of-the-art B\(_{0}\) shimming of the human heart at 7 T were described. Cardiac phase-specific shimming strategies were found to be superior to vendor-supplied shimming.},
  language  = {en}
}
@article{TraubGrondeyGassenmaieretal.2022,
  author    = {Traub, Jan and Grondey, Katja and Gassenmaier, Tobias and Schmitt, Dominik and Fette, Georg and Frantz, Stefan and Boivin-Jahns, Val{\´e}rie and Jahns, Roland and St{\"o}rk, Stefan and Stoll, Guido and Reiter, Theresa and Hofmann, Ulrich and Weber, Martin S. and Frey, Anna},
  title     = {Sustained increase in serum glial fibrillary acidic protein after first ST-elevation myocardial infarction},
  series = {International Journal of Molecular Sciences},
  volume    = {23},
  journal   = {International Journal of Molecular Sciences},
  number    = {18},
  issn      = {1422-0067},
  doi       = {10.3390/ijms231810304},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-288261},
  year      = {2022},
  abstract  = {Acute ischemic cardiac injury predisposes one to cognitive impairment, dementia, and depression. Pathophysiologically, recent positron emission tomography data suggest astroglial activation after experimental myocardial infarction (MI). We analyzed peripheral surrogate markers of glial (and neuronal) damage serially within 12 months after the first ST-elevation MI (STEMI). Serum levels of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) were quantified using ultra-sensitive molecular immunoassays. Sufficient biomaterial was available from 45 STEMI patients (aged 28 to 78 years, median 56 years, 11\% female). The median (quartiles) of GFAP was 63.8 (47.0, 89.9) pg/mL and of NfL 10.6 (7.2, 14.8) pg/mL at study entry 0-4 days after STEMI. GFAP after STEMI increased in the first 3 months, with a median change of +7.8 (0.4, 19.4) pg/mL (p = 0.007). It remained elevated without further relevant increases after 6 months (+11.7 (0.6, 23.5) pg/mL; p = 0.015), and 12 months (+10.3 (1.5, 22.7) pg/mL; p = 0.010) compared to the baseline. Larger relative infarction size was associated with a higher increase in GFAP (ρ = 0.41; p = 0.009). In contrast, NfL remained unaltered in the course of one year. Our findings support the idea of central nervous system involvement after MI, with GFAP as a potential peripheral biomarker of chronic glial damage as one pathophysiologic pathway.},
  language  = {en}
}
@article{ReiterDemirbasSchmalzingetal.2022,
  author    = {Reiter, Theresa and Demirbas, Senem and Schmalzing, Marc and Voelker, Wolfram and Bauer, Wolfgang R. and G{\"u}der, G{\"u}lmisal},
  title     = {CMR detects extensive intracavitary thrombi as solitary clinical presentation of Antiphospholipid Syndrome: A case report},
  series = {Clinical Case Reports},
  volume    = {10},
  journal   = {Clinical Case Reports},
  number    = {11},
  issn      = {2050-0904},
  doi       = {10.1002/ccr3.6568},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312766},
  year      = {2022},
  abstract  = {Intracavitary thrombi are an important differential diagnosis of cardiac masses. Cardiac magnetic resonance imaging (CMR) allows their non-invasive characterization. This case highlights extensive cardiac thrombi detected by CMR as solitary presentation of antiphospholipid syndrome.},
  language  = {en}
}