Diagnostic tests for the carotid artery include carotid ultrasound, carotid angiography, magnetic resonance angiography and computed tomography angiography, according to the National Heart, Lung and Blood Institute. These tests look for the presence of carotid artery disease and effects of a stroke or mini-stroke.
A carotid ultrasound inspects the structure of the carotid arteries and determines how much they've been narrowed by plaque. In a carotid angiography, a doctor injects dye into a vein and watches it as it travels through the carotid arteries. An MRA, which may also use dye, uses a magnetic resonance imager to provide pictures of the carotid arteries. CT angiography combines multiple X-rays to build a three-dimensional picture of the carotid arteries, as the NHLBI explains.