High-resolution, short echo time MR imaging of the fingers and wrist with a local gradient coil.

Abstract

The many fibrous tissues of the wrist and hand have short T2s, and, because of the small size of the tissues, their magnetic resonance (MR) imaging necessitates use of the high spatial resolution obtainable with fields of view as small as 2 cm x 2 cm x 1 mm. The authors demonstrate that the use of a local xyz gradient coil, positioned off-center in a clinical MR imager to facilitate patient positioning, permits acquisition of high-resolution images in spin-echo (SE) and gradient-recalled-echo (GRE) sequences with echo time (TE) as short as 6 msec (SE) or 3 msec (GRE). The authors compare this method for obtaining high-resolution images with the alternative method of using normal gradient strengths and increased pulse duration. The effects on image quality of TE, bandwidth, gradient strength, and chemical shift artifacts are presented. Images obtained with the local gradient coil of the carpal tunnel, carpal bones, and proximal interphalangeal joint in healthy volunteers are shown.