@misc{MartinFrauenrathZerdemetal.2011,
  author    = {Martin, Conrad Steven and Frauenrath, Tobias and Zerdem, Celal and Renz, Wolfgang and Niendorf, Thoralf},
  title     = {Evaluation of Magneto Alert Sensor (MALSE) to Improve MR Safety by Decreasing the Incidence of Ferromagnetic Projectile Accidents},
  series = {2011 ISMRM Annual Meeting Proceedings},
  journal   = {2011 ISMRM Annual Meeting Proceedings},
  issn      = {1545-4428},
  year      = {2011},
  abstract  = {The magnetic forces of fringe magnetic fields of MR systems on ferromagnetic components can impose a severe patient, occupational health and safety hazard. MRI accidents are listed as number 9 of the top 10 risks in modern medicine. With the advent of ultrahigh field MR systems including passively shielded magnet versions, this risk, commonly known as the missile or projectile effect is even more pronounced. A strategy employing magnetic field sensors which can be attached to ferromagnetic objects that are commonly used in a clinical environment is conceptually appealing for the pursuit of reducing the risk of ferromagnetic projectile accidents.},
  language  = {en}
}
@misc{FrauenrathRenzRiegeretal.2010,
  author    = {Frauenrath, Tobias and Renz, Wolfgang and Rieger, Jan and G{\"o}mmel, Andreas and Butenweg, Christoph and Niendorf, Thoralf},
  title     = {High Spatial Resolution 3D MRI of the Larynx Using a Dedicated TX/RX Phased Array Coil at 7.0T},
  series = {2010 ISMRM-ESMRMB joint annual meeting},
  journal   = {2010 ISMRM-ESMRMB joint annual meeting},
  issn      = {1545-4428},
  year      = {2010},
  abstract  = {MRI holds great potential for elucidating laryngeal and vocal fold anatomy together with the assessment of physiological processes associated in human phonation. However, MRI of human phonation remains very challenging due to the small size of the targeted structures, interfering signal from fat, air between the vocal folds and surrounding muscles and physiological motion. These anatomical/physiological constraints translate into stringent technical requirements in balancing, scan time, image contrast, immunity to physiological motion, temporal resolution and spatial resolution. Motivated by these challenges and limitations this study is aiming at translating the sensitivity gain at ultra-high magnetic fields for enhanced high spatial resolution 3D imaging of the larynx and vocal tract. To approach this goal a dedicated two channel TX/RX larynx coil is being proposed.},
  language  = {en}
}
@misc{HezelFrauenrathRenzetal.2010,
  author    = {Hezel, Fabian and Frauenrath, Tobias and Renz, Wolfgang and Schulz-Menger, Jeanette and Niendorf, Thoralf},
  title     = {Feasibility of CINE Myocardial T2* Mapping Using Susceptibility Weighted Gradient-Echo Imaging at 7.0 T},
  series = {2010 ISMRM-ESMRMB joint annual meeting},
  journal   = {2010 ISMRM-ESMRMB joint annual meeting},
  issn      = {1545-4428},
  year      = {2010},
  abstract  = {This study is designed to demonstrate the promise of susceptibility weighted 2D CINE FLASH and T2* Mapping of the heart at 7T.},
  language  = {en}
}
@misc{FrauenrathBeckerHezeletal.2010,
  author    = {Frauenrath, Tobias and Becker, Meike and Hezel, Fabian and Krombach, Gabriele A. and Kremer, Ute and Schulz-Menger, Jeanette and Niendorf, Thoralf},
  title     = {Comparison of Left Function Assessment Using Phonocardiogram and Electrocardiogram Triggered 2D SSFP CINE MR Imaging at 1.5 T and 3.0 T},
  series = {2010 ISMRM-ESMRMB joint annual meeting},
  journal   = {2010 ISMRM-ESMRMB joint annual meeting},
  issn      = {1545-4428},
  year      = {2010},
  abstract  = {As high-field cardiac MRI (CMR) becomes more widespread the propensity of ECG to distortions and mistriggering increases and with it the motivation for a cardiac triggering alternative. Hence, this study explores the suitability of acoustic cardiac triggering (ACT) for left ventricular (LV) function assessment in healthy subjects at 1.5T and 3.0T.},
  language  = {en}
}
@misc{DieringerRenzLindeletal.2010,
  author    = {Dieringer, Matthias A. and Renz, Wolfgang and Lindel, Tomasz and Seifert, Frank and Frauenrath, Tobias and Waiczies, Helmar and von Knobelsdorff-Brenkhoff, Florian and Santoro, Davide and Hoffmann, Werner and Ittermann, Bernd and Schulz-Menger, Jeanette and Niendorf, Thoralf},
  title     = {4CH TX/RX Surface Coil for 7T: Design, Optimization and Application for Cardiac Function Imaging},
  series = {2010 ISMRM-ESMRMB joint annual meeting},
  journal   = {2010 ISMRM-ESMRMB joint annual meeting},
  issn      = {1545-4428},
  year      = {2010},
  abstract  = {Practical impediments of ultra high field cardiovascular MR (CVMR) can be catalogued in exacerbated magnetic field and radio frequency (RF) inhomogeneities, susceptibility and off-resonance effects, conductive and dielectric effects in tissue, and RF power deposition constraints, which all bear the potential to spoil the benefit of CVMR at 7T. Therefore, a four element cardiac transceive surface coil array was developed. Cardiac imaging provided clinically acceptable signal homogeneity with an excellent blood myocardium contrast. Subtle anatomic structures, such as pericardium, mitral and tricuspid valves and their apparatus, papillary muscles, and trabecles were accurately delineated.},
  language  = {en}
}
@article{FrauenrathHezelRenzetal.2010,
  author    = {Frauenrath, Tobias and Hezel, Fabian and Renz, Wolfgang and de Geyer d'Orth, Thibaut and Dieringer, Matthias and von Knobelsdorf-Brenkenhoff, Florian and Prothmann, Marcel and Schulz-Menger, Jeanette and Niendorf, Thoralf},
  title     = {Acoustic cardiac triggering: a practical solution for synchronization and gating of cardiovascular magnetic resonance at 7 Tesla},
  series = {Journal of Cardiovascular Magnetic Resonance},
  volume    = {12},
  journal   = {Journal of Cardiovascular Magnetic Resonance},
  number    = {1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1532-429X},
  doi       = {10.1186/1532-429X-12-67},
  year      = {2010},
  abstract  = {Background To demonstrate the applicability of acoustic cardiac triggering (ACT) for imaging of the heart at ultrahigh magnetic fields (7.0 T) by comparing phonocardiogram, conventional vector electrocardiogram (ECG) and traditional pulse oximetry (POX) triggered 2D CINE acquisitions together with (i) a qualitative image quality analysis, (ii) an assessment of the left ventricular function parameter and (iii) an examination of trigger reliability and trigger detection variance derived from the signal waveforms. Results ECG was susceptible to severe distortions at 7.0 T. POX and ACT provided waveforms free of interferences from electromagnetic fields or from magneto-hydrodynamic effects. Frequent R-wave mis-registration occurred in ECG-triggered acquisitions with a failure rate of up to 30\% resulting in cardiac motion induced artifacts. ACT and POX triggering produced images free of cardiac motion artefacts. ECG showed a severe jitter in the R-wave detection. POX also showed a trigger jitter of approximately Δt = 72 ms which is equivalent to two cardiac phases. ACT showed a jitter of approximately Δt = 5 ms only. ECG waveforms revealed a standard deviation for the cardiac trigger offset larger than that observed for ACT or POX waveforms. Image quality assessment showed that ACT substantially improved image quality as compared to ECG (image quality score at end-diastole: ECG = 1.7 ± 0.5, ACT = 2.4 ± 0.5, p = 0.04) while the comparison between ECG vs. POX gated acquisitions showed no significant differences in image quality (image quality score: ECG = 1.7 ± 0.5, POX = 2.0 ± 0.5, p = 0.34). Conclusions The applicability of acoustic triggering for cardiac CINE imaging at 7.0 T was demonstrated. ACT's trigger reliability and fidelity are superior to that of ECG and POX. ACT promises to be beneficial for cardiovascular magnetic resonance at ultra-high field strengths including 7.0 T.},
  language  = {en}
}
@article{KobFrauenrath2009,
  author    = {Kob, Malte and Frauenrath, Tobias},
  title     = {A system for parallel measurement of glottis opening and larynx position},
  series = {Biomedical Signal Processing and Control},
  volume    = {4},
  journal   = {Biomedical Signal Processing and Control},
  number    = {3},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1746-8108},
  doi       = {10.1016/j.bspc.2009.03.004},
  pages     = {221 -- 228},
  year      = {2009},
  abstract  = {The simultaneous assessment of glottal dynamics and larynx position can be beneficial for the diagnosis of disordered voice or speech production and swallowing. Up to now, methods either concentrate on assessment of the glottis opening using optical, acoustical or electrical (electroglottography, EGG) methods, or on visualisation of the larynx position using ultrasound, computer tomography or magnetic resonance imaging techniques. The method presented here makes use of a time-multiplex measurement approach of space-resolved transfer impedances through the larynx. The fast sequence of measurements allows a quasi simultaneous assessment of both larynx position and EGG signal using up to 32 transmit-receive signal paths. The system assesses the dynamic opening status of the glottis as well as the vertical and back/forward motion of the larynx. Two electrode-arrays are used for the measurement of the electrical transfer impedance through the neck in different directions. From the acquired data the global and individual conductivity is calculated as well as a 2D point spatial representation of the minimum impedance. The position information is shown together with classical EGG signals allowing a synchronous visual assessment of glottal area and larynx position. A first application to singing voice analysis is presented that indicate a high potential of the method for use as a non-invasive tool in the diagnosis of voice, speech, and swallowing disorders.},
  language  = {en}
}
@article{HeinrichsUttingFrauenrathetal.2009,
  author    = {Heinrichs, Uwe and Utting, Jane F. and Frauenrath, Tobias and Hezel, Fabian and Krombach, Gabriele A. and Hodenius, Michael A. J. and Kozerke, Sebastian and Niendorf, Thoralf},
  title     = {Myocardial T2 mapping free of distortion using susceptibility-weighted fast spin-echo imaging: A feasibility study at 1.5 T and 3.0 T},
  series = {Magnetic Resonance in Medicine},
  volume    = {62},
  journal   = {Magnetic Resonance in Medicine},
  number    = {3},
  publisher = {Wiley-Liss},
  address   = {New York},
  issn      = {1522-2594},
  doi       = {10.1002/mrm.22054},
  pages     = {822 -- 828},
  year      = {2009},
  abstract  = {This study demonstrates the feasibility of applying free-breathing, cardiac-gated, susceptibility-weighted fast spin-echo imaging together with black blood preparation and navigator-gated respiratory motion compensation for anatomically accurate T₂ mapping of the heart. First, T₂ maps are presented for oil phantoms without and with respiratory motion emulation (T₂ = (22.1 ± 1.7) ms at 1.5 T and T₂ = (22.65 ± 0.89) ms at 3.0 T). T₂ relaxometry of a ferrofluid revealed relaxivities of R2 = (477.9 ± 17) mM⁻¹s⁻¹ and R2 = (449.6 ± 13) mM⁻¹s⁻¹ for UFLARE and multiecho gradient-echo imaging at 1.5 T. For inferoseptal myocardial regions mean T₂ values of 29.9 ± 6.6 ms (1.5 T) and 22.3 ± 4.8 ms (3.0 T) were estimated. For posterior myocardial areas close to the vena cava T₂-values of 24.0 ± 6.4 ms (1.5 T) and 15.4 ± 1.8 ms (3.0 T) were observed. The merits and limitations of the proposed approach are discussed and its implications for cardiac and vascular T₂-mapping are considered.},
  language  = {en}
}
@article{FrauenrathNiendorfKob2008,
  author    = {Frauenrath, Tobias and Niendorf, Thoralf and Kob, Malte},
  title     = {Acoustic method for synchronization of Magnetic Resonance Imaging (MRI)},
  series = {Acta Acustica},
  volume    = {94},
  journal   = {Acta Acustica},
  number    = {1},
  publisher = {Hirzel},
  address   = {Stuttgart},
  issn      = {1861-9959},
  doi       = {10.3813/AAA.918017},
  pages     = {148 -- 155},
  year      = {2008},
  abstract  = {Magnetic Resonance Imaging (MRI) of moving organs requires synchronization with physiological motion or flow, which dictate the viable window for data acquisition. To meet this challenge, this study proposes an acoustic gating device (ACG) that employs acquisition and processing of acoustic signals for synchronization while providing MRI compatibility, immunity to interferences with electro-magnetic and acoustic fields and suitability for MRI at high magnetic field strengths. The applicability and robustness of the acoustic gating approach is examined in a pilot study, where it substitutes conventional ECG-gating for cardiovascular MR. The merits and limitations of the ACG approach are discussed. Implications for MR imaging in the presence of physiological motion are considered including synchronization with other structure- or motion borne sounds.},
  language  = {en}
}
@article{vonKnobelsdorfBrenkenhoffFrauenrathProthmannetal.2010,
  author    = {von Knobelsdorf-Brenkenhoff, Florian and Frauenrath, Tobias and Prothmann, Marcel and Dieringer, Matthias A. and Hezel, Fabian and Renz, Wolfgang and Kretschel, Kerstin and Niendorf, Thoralf and Schulz-Menger, Jeanette},
  title     = {Cardiac chamber quantification using magnetic resonance imaging at 7 Tesla—a pilot study},
  volume    = {20},
  publisher = {Springer},
  address   = {Berlin, Heidelberg},
  issn      = {0938-7994},
  doi       = {10.1007/s00330-010-1888-2},
  pages     = {2844 -- 2852},
  year      = {2010},
  abstract  = {Objectives Interest in cardiovascular magnetic resonance (CMR) at 7 T is motivated by the expected increase in spatial and temporal resolution, but the method is technically challenging. We examined the feasibility of cardiac chamber quantification at 7 T. Methods A stack of short axes covering the left ventricle was obtained in nine healthy male volunteers. At 1.5 T, steady-state free precession (SSFP) and fast gradient echo (FGRE) cine imaging with 7 mm slice thickness (STH) were used. At 7 T, FGRE with 7 mm and 4 mm STH were applied. End-diastolic volume, end-systolic volume, ejection fraction and mass were calculated. Results All 7 T examinations provided excellent blood/myocardium contrast for all slice directions. No significant difference was found regarding ejection fraction and cardiac volumes between SSFP at 1.5 T and FGRE at 7 T, while volumes obtained from FGRE at 1.5 T were underestimated. Cardiac mass derived from FGRE at 1.5 and 7 T was larger than obtained from SSFP at 1.5 T. Agreement of volumes and mass between SSFP at 1.5 T and FGRE improved for FGRE at 7 T when combined with an STH reduction to 4 mm. Conclusions This pilot study demonstrates that cardiac chamber quantification at 7 T using FGRE is feasible and agrees closely with SSFP at 1.5 T.},
  language  = {en}
}