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In-vivo B0 shimming of the liver using a local array of shim coils in combination with 2nd order spherical harmonics at 7T

Lieke van den Wildenberg¹, Quincy van Houtum¹, Wybe van der Kemp¹, Catalina Arteaga de Castro¹, Alex Bhogal¹, Paul Chang², Sahar Nassirpour², and Dennis Klomp¹
¹Radiology Department, UMC Utrecht, Utrecht, Netherlands, ²MR Shim GmbH, Reutlingen, Germany

The B₀ field inhomogeneity in the liver at 7T can be reduced using a local shim coil array combined with 2^nd order spherical harmonics B₀ shimming correction methods which can potentially lead to an inhomogeneity reduction of 44%.

Figure 5: In-vivo B₀ field mapping of the liver in a healthy volunteer during free breathing with two different B₀ shimming methods: 1) scanner shim (2^nd order) and 2) array of shim coils in combination with the conventional second scanner shim. A: anterior, P: posterior, R: right, L: left, H: head, F: feet, and std: standard deviation.

Figure 1: A) The array of shim coils B) used around the body array in the 7T MR system