Moderate evidence supports not routinely using MRI for the diagnosis of carpal tunnel syndrome.
Management of Carpal Tunnel Syndrome
Endorsed by: ASSH, ASPS, ACR, ACS, ASA
There was one high quality study (Jarvik, 2002) evaluating MRI for the diagnosis of CTS. Findings on MRI had a weak or poor association as a rule out test for CTS as compared to a classic or probable hand pain diagram and nerve conduction study. Only severe fascicular swelling, severe flexor tenosynovitis, or severe increased muscle signal had a strong association with CTS, suggesting that MRI would be insensitive in identifying the diagnosis of CTS in the majority of patients in whom these findings would be unlikely to be present.