Gadolinium-Enhanced CT Angiography of the Circle of Willis and Neck

Summary: CT angiography (CTA) of the cervical and in-tracranial vessels is a rapid, noninvasive, and relatively inexpensive technique for the evaluation of vascular abnor-malities. Contraindications to the use of contrast media, however, can preclude use of iodinated agents for CTA. We report the use of gadolinium as contrast agent for CTA of the head and neck in three patients with contraindications to iodinated contrast agents. CT angiography (CTA) allows reliable pretreat-ment planning and diminishes evaluation time for most cases of aneurysmal subarachnoid hemorrhage (1). Indeed, the accuracy of CTA for aneurysm de-tection has been shown to exceed that of conventional digital subtraction arteriography and, by extension, MR angiography (MRA; 2). CTA is also highly accu