Cerebral angiography is an invasive test that involves the injection of contrast media into the carotid artery by means of a catheter. Radiographs are taken as the dye works its way through the cerebral circulation. Angiography may be utilized to identify bleeding aneurysms, vasospasm, and arteriovenous malformations, and to differentiate embolism from large artery thrombosis [Adams HP, et al, 1994. Mohr JP, 1992]. Cerebral angiography provides information on both arteries and veins, with sequential images showing arterial, capillary, and venous phases.

The role of conventional angiography in the management of acute stroke is controversial. The test itself is associated with a risk of stroke, since the catheter carrying the dye might dislodge plaque from the carotid wall. In addition, patients may be allergic to the contrast dye, and the dye has been associated with the development of renal failure, particularly when pre-existing kidney disease is present. Presently, angiography is performed mainly in selected patients, especially those in whom surgery (such as carotid endarterectomy or craniotomy for ruptured aneurysms or arteriovenous malformations) is considered.

Conventional angiography has been replaced by magnetic resonance angiography (MRA) in some patients with cerebrovascular disease [Bruno A, 1993]. A noninvasive test, MRA permits the visualization of blood flow in vessels without the need for catheters or contrast agents. The technology can yield information regarding collateral blood flow and is nearly as effective as conventional angiography in estimating disease at the carotid bifurcation.

This left common carotid angiogram shows complete occlusion of the left middle cerebral artery distal to the origin of the anterior temporal branch.