T2 mapping of the median nerve in patients with carpal tunnel syndrome and healthy volunteers.

INTRODUCTION: We investigated the changes in MRI T2 mapping values in subjects with carpal tunnel syndrome (CTS) compared to healthy controls. METHODS: We enrolled 71 patients with CTS and 26 healthy controls. Median nerve T2 values were measured at the distal carpal tunnel, hamate bone, proximal carpal tunnel, and forearm levels. These were compared between patients and controls and correlated with median nerve cross-sectional area (CSA) and nerve conduction measurements. RESULTS: The mean T2 values at the proximal carpal tunnel levels were higher in the CTS group (56.7 ms) than in the control group (51.2 ms, P = .02) and also were higher than at the distal carpal tunnel (51.0 ms, P < .001) and forearm levels (47.6 ms, P < .001). T2 values were not significantly associated with CSA or nerve conduction measurements. DISCUSSION: T2 mapping of the carpal tunnel provides qualitative information on median nerve pathology but does not reflect CTS severity.