Diffusion tensor imaging in carpal tunnel syndrome.

Purpose: We aimed to investigate the efficacy of diffusion tensor imaging in the diagnosis of carpal tunnel syndrome and to obtain a quantitative parameter that may contribute to the diagnosis.

Materials And Methods: The median nerves in 57 wrists of 38 patients diagnosed as carpal tunnel syndrome and 30 wrists of 24 normal subjects were prospectively evaluated with a 3T Philips scanner, using standard 8-channel SENSE head coil. Diffusion tensor imaging was performed using spin echo-echo planar imaging. For anatomical reference, a T1-weighted sequence was acquired. Fractional anisotropy and apparent diffusion coefficient measurements were done focally at the carpal tunnel level and from whole median nerve.

Results: In carpal tunnel syndrome patients, both focal carpal tunnel and whole nerve measurements demonstrated statistically significantly lower fractional anisotropy values than normal subjects (P < 0.001). No statistically significant difference was observed in apparent diffusion coefficient measurements. The cut-off value obtained by receiver operator characteristics analysis was 0.554 for focal carpal tunnel fractional anisotropy (sensitivity, 80%; specificity, 80%) and 0.660 for whole nerve fractional anisotropy (sensitivity, 82%; specificity, 80%) measurement.

Conclusion: Diffusion tensor imaging may contribute to the diagnosis of carpal tunnel syndrome on the basis of fractional anisotropy measurements.