Real-time shimming of respiration-induced B0 fluctuations in the spinal cord with an integrated RF/shim iPRES(3) coil array

Motivation: Minimizing spatial and temporal magnetic field variations is essential for accurate diffusion and functional MRI of the spinal cord. Goal(s): Perform real-time shimming of respiration-induced B0 fluctuations in the spinal cord by using an integrated RF/shim coil array with multiple DC loops per RF coil element (iPRES(3)). Approach: The optimal DC currents to shim the B0 inhomogeneities at any breathing level were updated in real time based on the signal from a respiratory belt while acquiring ∆B0 maps and EPI images. Results: Static and respiration-induced B0 inhomogeneities were reduced by 57.5% and the temporal SNR of the EPI images was increased by 22.9%. Impact: Real-time shimming of the spinal cord with the iPRES(3) coil array can effectively reduce both spatial and temporal B0 variations caused by breathing, which is expected to enable more accurate diffusion and functional MRI of the spinal cord.