CT angiography of the neck and brain arteries (supra-aortic trunks, circle of Willis)

CT angiography is a CT scan performed during a rapid injection of iodinated contrast, at the moment the contrast fills the arteries. It gives a precise image of the blood vessels without inserting a catheter into the arteries. CT angiography of the supra-aortic trunks examines the large neck arteries that run up to the brain (carotid and vertebral arteries). Brain CT angiography, or CT of the circle of Willis, examines the network of arteries at the base of the brain. It is requested particularly for stroke (in an emergency, to look for a blocked artery), to measure a narrowing of a carotid artery found on Doppler ultrasound, or to look for or monitor an aneurysm (a bulge in a brain artery).