Double loop receiver coil for MR imaging at 0.15 T.

A receiver coil of a cross-coupled, double loop geometry has been developed. This coil has a higher signal-to-noise (S/N) ratio and more homogeneous signal intensity at increasing depth than a conventional surface coil. Improvements in S/N of 51-256% compared with the commercial half-saddle body coil have been demonstrated in a 0.15 T resistive instrument. The new coil permits reduction in pixel volume using higher field gradients and thinner slices or time savings using fewer signal averages. The double loop coil provided higher S/N for lumbar spine imaging than an oval surface coil. Limitations of this type of coil design are increased sensitivity to respiratory motion artifacts and limitation of the size of the subject that may be imaged. Using the double loop coil, the capability of our instrument to image the heart, pelvis, hip, and shoulder has been substantially improved.