High-resolution simulation of B 0 field conditions in the human heart from segmented computed tomography images.

B 0 inhomogeneity leads to imaging artifacts in cardiac magnetic resonance imaging (MRI), in particular dark band artifacts with steady-state free precession pulse sequences. The limited spatial resolution of MR-derived in vivo B 0 maps and the lack of population data prevent systematic analysis of the problem at hand and the development of optimized B 0 shim strategies. We used readily available clinical computed tomography (CT) images to simulate the B 0 conditions in the human heart at high spatial resolution. Calculated B 0 fields showed consistency with MRI-based B 0 measurements. The B 0 maps for both the simulations and in vivo measurements showed local field inhomogeneities in the vicinity of lung tips with dominant Z3 spherical harmonic terms in the field distribution. The presented simulation approach allows for the derivation of B 0 field conditions at high spatial resolution from CT images and enables the development of subject- and population-specific B 0 shim strategies for the human heart.