VOI-Based Fourier Transform Method for Rapid Partial Calculation of B0 Maps from Sparse Susceptibility Distributions

Rahul Dewal¹, Qing X. Yang¹

Calculation of B₀ field inhomogeneity maps from susceptibility models via convolution with dipole kernels is limited by computer memory (RAM) and calculation time requirements in the case of large data matrices. In some applications, only small portions of the full matrix may be of interest as a susceptibility perturbation source or as a volume of interest (VOI). A VOI-based approach is here proposed that can reduce memory usage or calculation time in this sparse case. The method can be expected to accelerate various applications, such as passive shimming simulations and patient-specific B₀ field calculations derived from anatomic scans.