Surgical wound monitoring by MRI with a metamaterial-based implanted local coil

Abstract

An implantable sensor for monitoring surgical wounds after bowel reconstruction is proposed. The sensor consists of a coupled pair of 8-element magneto-inductive ring resonators, designed for mounting on a biofragmentable anastomosis ring to give a local increase in signal-to-noise ratio near an annular wound during 1 H magnetic resonance imaging. Operation on an anti-symmetric spatial mode is used to avoid coupling to the B 1 field during excitation, and a single wired connection is used for MRI signal output. The electrical response and field-of-view are estimated theoretically. Prototypes are constructed from flexible elements designed for operation at 1.5T, electrical responses are characterized and local SNR enhancement is confirmed using agar gel phantoms.