Magnetic resonance imaging in the diagnosis of occult dorsal wrist ganglions.

Small occult dorsal wrist ganglia, which are not visible or palpable, may be painful. Clinically, there is tenderness over the scapholunate ligament and pain with hyperextension of the wrist with normal radiographs and an otherwise normal examination. We reviewed 20 patients with suspected occult ganglia who underwent an MRI scan and subsequently underwent surgical excision of the cyst. We compared the MRI diagnosis with the intra-operative findings and the histological evaluation of the surgical specimen to determine the accuracy of MRI in identifying an occult ganglion. When intra-operative determination of disease was used as a standard, the sensitivity of MRI scanning was 83%, the specificity was 50%, the positive predictive value was 94% and the accuracy 80%. Using histology as the standard, the sensitivity was 80%, the specificity 20%, and the positive predictive value 75%.