A5064798631- Advanced MRI Techniques and Applications
- Advanced NMR Techniques and Applications
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Topology Optimization in Engineering
- MRI in cancer diagnosis
- Advanced Numerical Methods in Computational Mathematics
- Electric Motor Design and Analysis
- Speech and Audio Processing
- Underwater Acoustics Research
- Advanced Neuroimaging Techniques and Applications
- Direction-of-Arrival Estimation Techniques
- Advanced Algorithms and Applications
- Electrical and Bioimpedance Tomography
- Underwater Vehicles and Communication Systems
- Advanced Mathematical Modeling in Engineering
- Advanced Measurement and Detection Methods
- Winter Sports Injuries and Performance
- Magnetic Field Sensors Techniques
- NMR spectroscopy and applications
- Composite Material Mechanics
- Forest, Soil, and Plant Ecology in China
- Ultrasound Imaging and Elastography
- Nuclear Physics and Applications
- Electromagnetic Simulation and Numerical Methods
University Medical Center Freiburg
2013-2025
University of Freiburg
2009-2025
Harbin Institute of Technology
2025
Southwest China Institute of Electronic Technology
2020
Harbin Engineering University
2018
Ministry of Industry and Information Technology
2018
Yamaha (Japan)
2014
Leshan Normal University
2010
Chinese People's Liberation Army
2010
Academy of Mathematics and Systems Science
2004
Implementing new magnetic resonance experiments, or sequences, often involves extensive programming on vendor-specific platforms, which can be time consuming and costly. This situation is exacerbated when research sequences need to implemented several platforms simultaneously, for example, at different field strengths. work presents an alternative environment that hardware-independent, open-source, promotes rapid sequence prototyping.A novel file format described efficiently store the...
An efficient and reliable a posteriori error estimate is derived for linear parabolic equations which does not depend on any regularity assumption the underlying elliptic operator. adaptive algorithm with variable time-step sizes space meshes proposed studied which, at each time step, delays mesh coarsening until final iteration of procedure, allowing only size refinements before. It proved that step able to reduce indicators (and thus error) below given tolerance within finite number steps....
Purpose Design, implement, integrate, and characterize a customized coil system that allows for generating spatial encoding magnetic fields (SEMs) in highly‐flexible fashion. Methods A gradient with high number of individual elements was designed. Dimensions the were chosen to mimic whole‐body system, scaled down head insert. Mechanical shape wire layout each element optimized increase local strength while minimizing eddy current effects simultaneously considering manufacturing constraints....
Abstract Purpose This study investigates peripheral nerve stimulation (PNS) safety thresholds for health professionals performing MRI procedures and the variation of arm rotations in close vicinity to magnet bore. Methods Employing two posable human body models, this research utilized quasi-static electromagnetic calculations neurodynamic simulations assess PNS thresholds. Different are compared standing interventionalist’s posture assuming supine patient position, typical medical...
A multi-coil shim setup is designed and optimized for human brain shimming. Here, the size position of a set square coils are to improve performance without increasing number local coils. Utilizing such especially beneficial at ultrahigh fields where B0 inhomogeneity in more severe.The optimization started with symmetric arrangement 32 independent Three parameters per coil were parallel, including angular axial positions on cylinder surface coil, which constrained by size, construction...
An element-local $L^2$-projected $C^0$ finite element method is presented to approximate the nonsmooth solution being not in $H^1$ of Maxwell problem on a nonconvex Lipschitz polyhedron with reentrant corners and edges. The key idea lies that $L^2$ projectors are applied both curl div operators. linear (enriched certain higher degree bubble functions) employed solution. coercivity norm established uniform mesh-size, condition number ${\cal O}(h^{-2})$ resulting system proven. For its $H^r$...
Purpose An automated algorithm for generating realizable MR gradient and shim coil layouts based on the boundary element method is presented here. The overall goal to reduce postprocessing effort thus enable rapid prototyping of new designs. For a given surface mesh target field, generates connected, non‐overlapping wire path. Methods proposed consists several steps: Stream function optimization, two‐dimensional projection, potential discretization, topological contour sorting, opening...
Purpose The purpose of this study is to introduce a novel design method shim coil array specifically optimized for whole brain shimming and compare the performance resulting coils conventional spherical harmonic shimming. Methods proposed approach based on stream function singular value decomposition. Eighty‐four field maps from 12 volunteers measured in seven different head positions were used during process. cross validation technique was applied find an optimal number elements array....
Recently, matrix gradient coils (also termed multi-coils or multi-coil arrays) were introduced for imaging and B0 shimming with 24, 48, even 84 coil elements. However, in applications, providing one amplifier per element is not always feasible due to high cost technical complexity. In this simulation study, we show that an 84-channel (head insert brain imaging) able create a wide variety of field shapes if the number amplifiers reduced. An optimization algorithm was implemented obtains...
Purpose Multiple nonlinear gradient fields offer many potential benefits for spatial encoding including reduced acquisition time, fewer artefacts and region‐specific imaging, although designing a suitable trajectory such setup is difficult. This work aims to optimize trajectories multiple based on the image signal‐to‐noise ratio. Theory Methods Image ratio directly linked covariance of reconstructed pixels, which can be calculated recursively each projection under Bayesian formulation. An...
The design of coil for magnetic resonance image (MRI) application is an optimization problem, in which a specified distribution the field inside region interest generated by choosing optimal current density on non-intersecting surface. This paper proposes iterative method designing MRI coils cylindrical surface using piecewise discretized scalar stream function as variable. accurately calculated interpolation with smoothness based developable property are designed bi-objective functions and...
Purpose To improve intraoral transverse loop coil design for high‐resolution dental MRI. Methods The (tLoop) was modified (mtLoop) by overlapping the feed port conductors, bending posterior section, introducing a parallel plate capacitor, optimizing insulation thickness, and using it in receive‐only mode. In addition, an MR‐silent introduced. performances of mtLoop tLoop coils were compared terms sensitivity, image SNR, eddy currents electromagnetic simulations MRI measurements at 3T....
Abstract A cylindrical head gradient insert for human imaging with non‐linear spatial encoding magnetic fields (SEMs) has been designed, optimized and successfully integrated a modified 3T clinical MR system. This PatLoc (parallel acquisition technique using localized gradients) SEM coil uses SEMs that resemble second‐order shim fields, but much higher amplitude as well the possibility rapid switching. work describes optimization of design measurement methods to characterize its SEMs,...
With advantages of reduced coupling and compact structure, Matrix Coils (MCs) design extension to approximate multiple target inhomogeneities is necessary improve its performance in shimming applications.A Spherical Harmonics Decomposition Method (SHDM) proposed for the multi-target MCs optimization problem. The magnetic field generated by represented form SHs' orthogonal basis, based on which pattern optimized adapt SH targets.With SHs 1st, 3rd, mixed 1st&2nd degrees Halbach magnet...
The design of gradient coils is sometimes perceived as complex and counterintuitive. However, a current density connected to stream function in fact by simple relation. Here we present an intuitive open source code collection derive functions from densities on surface geometries. Discrete thin wires, oriented orthogonally the main magnetic field direction are used describe density. An inverse problem solved derived find coil designs domains. flexibility method demonstrated deriving several...
Depth discrimination is a key procedure in acoustic detection or target classification for low-frequency underwater sources. Conventional depth-discrimination methods use vertical line array, which has disadvantage of poor mobility due to the size sensor array. In this paper, we propose method sources using horizontal array (HLA) vector sensors based on mode extraction. First, establish linear equations related modal amplitudes beamforming space. Second, solve by introducing total least...
Diffusion weighting in optically detected magnetic resonance experiments involving diamond nitrogen-vacancy (NV) centers can provide valuable microstructural information. Bi-planar gradient coils employed for diffusion afford excellent spatial access, essential integrating the NV-NMR components. Nevertheless, owing to polar tilt of roughly [Formula: see text] NV center, primary field direction must be taken into account accordingly.To determine most effective bi-planar coil configurations,...