CT myelography for outpatients. An inpatient/outpatient pilot study to assess methodology.

The diagnostic usefulness, limitations, and adverse reactions associated with computed tomographic myelography using metrizamide were assessed for broad outpatient application. The initial approach was to examine inpatients (n = 38) with low-dose metrizamide (100 mgI/ml). This low dose was believed less likely to be associated with side effects. They were then treated as if they were outpatients, with the liberties this entailed. The consequences of needle puncture were minimized by using a 25-gauge disposable needle. Thirty-four (89%) patients remained free of side effects after the procedure. Subsequently, this technique was extended to 42 outpatients, 38 (90.5%) of whom remained asymptomatic. For comparison, 170 mgI/ml was used in another 25 outpatients, who evidenced more symptoms. The potential medical, economic, and therapeutic benefits of obviating hospitalization by safer outpatient CT myelography seem clear.