CARPAL-TUNNEL SYNDROME - EVALUATION OF MEDIAN NERVE CIRCULATION WITH DYNAMIC CONTRAST-ENHANCED MR-IMAGING

PURPOSE: To identify mechanism(s) responsible for carpal tunnel syndro me (CTS). MATERIALS AND METHODS: At dynamic gadolinium-enhanced magnet ic resonance (MR) imaging, the enhancement pattern of the sagittal sec tion of the median nerve in 10 wrists of nine patients with CTS (two m en and seven women, aged 43-60 years [mean, 52 years 10 months]) was s tudied while each wrist was in a neutral, flexed, and/or extended posi tion. Five asymptomatic volunteers (four men and one woman, aged 23-54 years [mean, 31 years 5 months]) also underwent MR imaging to establi sh the normal enhancement patterns. RESULTS: Two distinctly abnormal p atterns of median-nerve enhancement were revealed: marked or no enhanc ement. Marked enhancement was attributed to nerve edema, and the lack of enhancement was attributed to ischemia. Marked enhancement changed to no enhancement when the wrists were in a flexed or extended positio n. This change was associated with an aggravation of the symptoms of C TS. CONCLUSIONS: CTS may result from a circulatory disturbance rather than from deformation or compression of the nerve.