Computed tomography of granulomatous basal arachnoiditis.

Clinical findings are often insufficient to diagnose basal arachnoiditis and conventional neuroradiological techniques often fail to demonstrate the inflammatory process. Computed tomographic (CT) scans, however, usually can demonstrate the circle of Willis, and the basilar, sylvian quadrigeminal, and vermian cisterns. Cisternal anatomy can also be delineated on the CT scans by metrizamide cisternography. CT scanning may prove to be the most accurate and sensitive radiographic test for basal arachnoiditis. Findings in three patients are reported.