High-resolution MR imaging using loop-gap resonators. Work in progress

Representative results using loop-gap resonator (LGR) configurations for local high-resolution MR imaging (0.6 mm X 0.6 mm pixel size with 3-mm section thickness) are presented. Four geometries were employed: flat single loops, coplanar (planar pair) loops, coaxial (axial pair) loops, and symmetrically angled (butterfly pair) loops. The LGRs were used as receiver coils with the body coil as transmitter. Butterfly pairs and planar pairs are intrinsically decoupled from a transmitted field of arbitrary orientation, whereas the single loops and axial pairs are decoupled from a field that is linearly polarized and orthogonal to its axis. The coils were evaluated using computer-generated and experimentally determined field distributions and by the imaging of human subjects on a 1.5-T MR system. Matching the region of sensitivity of the coil to the region of anatomic interest is emphasized.