Low-dose metrizamide spinal computed tomography in outpatients.

: Delineation of the thecal sac in CT can be improved by the presence of intrathecal metrizamide. This may be especially helpful in postoperative patients in whom the landmarks are often obscured by epidural scarring. Metrizamide-enhanced CT was performed on outpatients using 2 1/2 ml metrizamide (170 mg I/ml). Follow-up is available on 40 patients. The procedure was well tolerated with only three instances of severe headache, one case of vomiting, and no reported seizures. Adequate opacification was obtained at 92% of the levels examined with fair opacification at the remainder of the levels. This technique is considered a safe and useful outpatient procedure.