A5072355009- Advanced MRI Techniques and Applications
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Advanced Neuroimaging Techniques and Applications
- MRI in cancer diagnosis
- Advanced NMR Techniques and Applications
- Cardiac Imaging and Diagnostics
- NMR spectroscopy and applications
- Neurological disorders and treatments
- Nuclear Physics and Applications
- Wireless Body Area Networks
- Cardiac electrophysiology and arrhythmias
- Wireless Power Transfer Systems
- Lanthanide and Transition Metal Complexes
- Healthcare and Venom Research
- Numerical methods in inverse problems
- Acoustic Wave Phenomena Research
- Power Transformer Diagnostics and Insulation
- Advanced X-ray Imaging Techniques
- Restraint-Related Deaths
- Genetic Neurodegenerative Diseases
- Superconducting Materials and Applications
- Hernia repair and management
- Toxoplasma gondii Research Studies
- Neurological and metabolic disorders
University of Bayreuth
2022
Siemens (Germany)
1995-2016
Siemens Healthcare (Germany)
1993-2015
Siemens Healthcare (United States)
2004
University of Münster
1993
Fischer (Germany)
1991
Lawrence Berkeley National Laboratory
1991
University of Bonn
1958
University of Würzburg
1901
Echo planar imaging is characterized by scanning the 2D k-space after a single excitation. Different sampling patterns have been proposed. A technically feasible method uses sinusoidal readout gradient resulting measured data that does not sample in an equidistant manner. In order to employ conventional 2D-FFT image reconstruction, be converted cartesian grid. This can done either interpolation or alternatively generalized transformation. Filtering methods are described minimize ghosting...
Abstract Slice‐selective RF waveforms that mitigate severe B inhomogeneity at 7 Tesla using parallel excitation were designed and validated in a water phantom human studies on six subjects 16‐element degenerate stripline array coil driven with butler matrix to utilize the eight most favorable birdcage modes. The waveform design applied magnitude least‐squares (MLS) criteria an optimized k ‐space trajectory significantly improve profile uniformity compared conventional (LS) designs. Parallel...
"History, of course, is difficult to write, if for no other reason, than that it has so many players and authors." – P. J. Keating (former Australian Prime Minister) Starting with post-war developments in nuclear magnetic resonance (NMR) a race stronger fields begun the 1950s overcome inherently low sensitivity this promising method. Further challenges were larger magnet bores accommodate small animals eventually humans. Initially, resistive electromagnets pole distances, or sample volumes,...
Abstract Spatially selective RF waveforms were designed and demonstrated for parallel excitation with a dedicated eight‐coil transmit array on modified 3T human MRI scanner. Measured profiles of individual coils in the used low‐flip‐angle pulse design to achieve desired spatial target two‐ (2D) three‐dimensional (3D) k ‐space simultaneous transmission eight channels. The 2D excited high‐resolution pattern in‐plane, while 3D trajectory produced high‐quality slice selection uniform in‐plane...
With magnetic resonance (MR) imaging, accurate spatial information—critical for effective stereotaxy—demands a homogeneous static field and linear gradients. Inhomogeneities nonlinearities induced by eddy currents during the pulse sequences distort images produce spurious displacements of stereotactic coordinates in both x-y plane z axis. These errors position can be assessed means two phantoms placed within guidance system—a "two-dimensional phantom" displaying "pincushion" distortion image...
To evaluate the physiological thresholds of neuromuscular stimulation relevant to very fast NMR imaging studies that use gradient switching at frequencies 1–2 kHz and a maximum magnetic field up 10 mT, series were done with human volunteers using an experimental echo planar coil set. The threshold for induction localized momentary sensations in back abdomen subjects is 60 T/s sinusoi-dally oscillating fields 1.27 kHz. relates E 6 V/m shown vary number oscillations frequency accord theory....
In national and international bodies, there is active discussion of appropriate safety regulations levels magnetic field strength in MRI. Present limits are usually expressed terms the switching rate dB/dt, but validity this open to debate. Application fundamental law electrostimulation well-established, both on theoretical experimental grounds. law, combination with Maxwell's yields a very simple equation that we call magnetostimulation. This has hyperbolic form strength-duration curve...
The high uncertainties, investments, and demands related to digital transformation are especially crucial for resource constraint small medium sized family firms. Our qualitative case study resonates with previous research, finding that such firms show low levels of strategizing a pragmatic-incremental approach transformation, often hindered by their traditionalism. In addition, we reveal tend follow reactive transformation. A reactivity trap appears when they operate in strongly regulated...
Rationale and Objectives A cardiac imaging pilot study was performed on 1.5 3.0 Tesla (T) whole body magnetic resonance units equipped with identical gradient sets geometrically equivalent coils. The goals were to compare the signal-to-noise (SNR) contrast-to-noise (CNR) ratios matched studies conducted at both field strengths demonstrate potential for functional morphologic evaluation T. Methods Short axis cine true fast steady precession (True FISP) compared T using coil in...
Abstract Chemical shift imaging benefits from signal‐to‐noise ratio (SNR) and chemical dispersion increases at stronger main field such as 7 Tesla, but the associated shorter radiofrequency (RF) wavelengths encountered require B mitigation over both spatial of view (FOV) a specified spectral bandwidth. The bandwidth constraint presents challenge for previously proposed spatially tailored methods, which are based on type echovolumnar trajectory referred to “spokes” or “fast‐k z ”. Although...
Ultra-high-field MRI (7 Tesla (T) and above) elicits more temporary side-effects compared to 1.5 T 3 T, e.g. dizziness or "postural instability" even after exiting the scanner. The current study aims assess quantitatively vestibular performance before exposure different scenarios at 7 0 T. Sway path body axis rotation (Unterberger's stepping test) were recorded in a total of 46 volunteers before, 2 minutes after, 15 scenarios: head (n = 27), no RF 22), only B0 20), & out 15). All lasted 30...
Abstract An eight‐rung, 3T degenerate birdcage coil (DBC) was constructed and evaluated for accelerated parallel excitation of the head with eight independent channels. Two mode configurations were tested. In first, each loops formed by individually excited, producing an pattern similar to a loop array. second configuration Butler matrix transformed this “loop coil” basis set into representing orthogonal modes coil. case rung currents vary sinusoidally around only four have significant...
Abstract Echo‐planar magnetic resonance (MR) imaging was used to observe signal intensity changes in the human brain during hypoxia. Increasing arterial blood levels of deoxyhemoglobin (0%–42%) prolonged apnea were monitored with a pulse oximeter and correlated gray matter white attenuation 13% 20%, respectively. The results suggest possibility using boluses as physiologic, intravascular susceptibility contrast agent for assessment local cerebral oxygen utilization.