Reduction of field of view in MRI using a surface-spoiling local gradient insert.

Herein is presented a method for suppressing the magnetic resonance signal to a controlled depth by applying a spatially heterogeneous spoiler field between the slice-select and readout pulses. Eliminating the signal from near-surface regions allows one to shrink the field of view without introducing aliasing artifacts, thereby decreasing imaging time over a smaller defined volume. A unique planar magnetic gradient coil was constructed to generate the spoiler field. Phantom and human subject studies showed that the signal can be suppressed to controlled distances of up to 90 mm from the coil, with modest requirements on power supplies, pulse sequences, and materials, and with no increase in imaging time.