Bloch simulations with intra-voxel spin dephasing

Flow MRI simulation in complex 3D geometries: Application to the cerebral venous network

“…Contrary to biological tissues, which have a virtually continuous distribution of spins, a discrete distribution of isochromats can lead to constructive magnetization summation inside a voxel and to artificial spin refocusing . Some simulators work around this problem by estimating intravoxel dephasing from gradient magnitudes, by calculating additional points, by controlling decay with a specific variable, by calculating intravoxel magnetization gradients or by nulling the transverse magnetization artificially when a spoiling gradient is applied (however, this last solution can avoid some realistic spin refocusing from one TR to the next). In the present framework, increasing the number of particles per voxel is the most natural way to circumvent the problem, although this method substantially increases computation times.…”

Pulseq: A rapid and hardware-independent pulse sequence prototyping framework

“…The target sequence was simulated in JEMRIS using the calculated parameter maps and an image was generated with a 2D discrete Fourier transform (DFT). The low resolution of the target sequence allows the simulations to accurately capture intra‐voxel dephasing .…”

Virtual clinical trials in medical imaging: a review

“…Several simulators have been developed for MRI since the 1980s when the foundations of MRI imaging were laid. [160][161][162][163][164][165][166][167][168][169][170][171][172][173] The fundamental component of any MRI simulator is an efficient solver of the generalized Bloch-Torrey equation. [174][175][176] Several solvers have been proposed in the literature.…”