Intravenous contrast computerized tomography (CT) was performed in 200 patients with cerebral infarction. Of 100 patients who had CT performed after bolus injection of 50 mL of 60% iodinated contrast material, enhancement was seen in five (5%). This compared with enhancement seen in 65% of patients with cerebral infarction studied after drip infusion of 300 mL of 30% iodinated contrast material. The enhancement occurred between the end of the first week and and the end of the fourth week after development of neurological abnormalities. Follow-up CT showed disappearance or marked reduction in the intensity of enhancement within 21 days of the initial CT study. Peripheral ring or diffuse enhancement were nospecific, but certain patterns were highly specific for infarction and included dense enhancement within deep nuclear gray matter (putamen, caudate, thalamus) and tubular-shaped or gyral enhancement with intervening low-density portions and minimal or no mass effect. Cerebral infarction was confirmed in all cases by clinical course, angiography, or subsequent CT.