CT cisternography with intracranial arachnoidal cysts.

Four patients with an intracranial arachnoidal cyst studied by computed tomography are reported. On the routine CT scan, arachnoid cysts are well defined lesions with the same density as cerebrospinal fluid and are not enhanced with contrast. Metrizamide CT cisternography further provides precise anatomic and physiologic information which may be difficult to obtain by angiography or air encephalography.