A resistive-shim system was constructed to correct the >100ppm magnetic-field inhomogeneity caused by implanted ICDs, which leads to signal loss and blurring in cardiac MRI. A plastic platform, held to the MRI stretcher, allows human-subject insertion, and holds a sensitive 720 Ampere*turns dipole-approximating shim-coil on a movable-fixture above the chest. Shim-coil is electronically decoupled from gradients and body-coil-RF. ICD field-inhomogeneity is measured with B0 mapping, and a correction field computed (shim-coil-center-location, DC-current-intensity). Shim-coil is moved to shim-coil-center-location, and a power-supply sends DC-current to the shim-coil. System was tested on phantoms overlaid with ICDs and corrected >75ppm inhomogeneity over 50x50x50mm3 FOV.
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