High-resolution MR imaging of the carpal tunnel and the wrist. Applicationof a 5-cm surface coil

Purpose. To make a comparative analysis of transversal tomograms obtained b y high-resolution MR imaging with frozen cross-sections of an anatomical fo rearm specimen. Twenty-two healthy volunteers were also examined using the same coil system to test for a range of possible clinical applications and for the depiction of morphological and morphometrical values of normal anat omy in vivo. Material and Methods, MR images of the carpal tunnel of 22 healthy voluntee rs were obtained with a 1.5-T whole-body system with a 5-cm surface coil. M easurements were recorded with a field-of-view between 50x50 mm(2) and 60x6 0 mm(2) in a 256x256 pixel matrix for the T1 sequence. A slice thickness of 2 mm was used. The images were acquired using a T1-weighted SE sequence (T R/TE 500/38 ms) and a T2-weighted SE sequence (TR/TE 2000/70 ms). Additiona lly, a formalin-fixed anatomical forearm specimen was imaged for anatomic c orrelation. The imaged transversal cross-section levels in the specimen wer e subsequently freeze-sectioned. The anatomical structures of the MR findin gs were identified and compared with the macroscopical sections of the spec imen. Results. Based on the good depiction of details at this coil system with a pixel size in T1 of 0.195x0.195 mm, high-resolution MR imaging enabled iden tification of the interior structures of the carpal tunnel, as well as deli neation of connective tissue. The clinical value of high-resolution MR incl udes the diagnosis of carpal tunnel syndrome and inflammatory disorders of the wrist. Conclusion: Our results support the feasibility of high-resolution MR imagi ng of the carpal tunnel and the wrist using small surface coils.