CT in evaluation of the circle of Willis.

The method of visualizing the circle of Willis intentionally on contrast-enhanced CT scan was studied. The incidence of circle of Willis in our series was 86%. Only mild side effects were observed, in 7.5% of cases. CT of 60 proven cerebral aneurysms were reviewed and aneurysm was detected in 57%. This method has the potential to be a noninvasive screening procedure for evaluation of suspected cerebral aneurysm, as well as evaluation of marked arteriosclerosis, occlusion of major arteries, and mass effect of parasellar tumors.