Cerebral angiography (using a catheter)

To obtain detailed images of blood vessels of the brain, such as the arteries that carry blood from the heart to the brain (carotid and vertebral arteries)

Most often done before procedures such as angioplasty, placement of stents, or surgery to repair an aneurysm (a bulge in an artery)

Computed tomography (CT), with or without a radiopaque contrast agent (which can be seen on x-rays)

To identify structural abnormalities (such as abscesses, tumors, and hydrocephalus) in the brain

To identify bleeding or evidence of strokes in the brain

To identify ruptured or herniated disks in the spine

To identify spinal fractures

To monitor the effects of radiation therapy on brain cancer or of antibiotics on a brain abscess

CT angiography (CTA) with a radiopaque contrast agent

To obtain detailed images of blood vessels of the brain and identify clots in arteries in people who have had a stroke (CTA has largely replaced cerebral angiography)

Doppler ultrasonography of the carotid arteries and the arteries at the base of the brain (transcranial)

To identify and evaluate narrowing or blockage of arteries in the neck and head and thus assess the risk of stroke

Most often done to evaluate people who have had a transient ischemic attack after the attack and over time

Magnetic resonance imaging (MRI)

To identify structural abnormalities (such as abscesses, tumors, and hydrocephalus) in the brain (images of the brain tissue are clearer and more detailed than those provided by CT, but MRI may not be as readily available)

To identify abnormalities, such as abscesses, tumors, and syrinx (a fluid-filled cavity) in the spinal cord

Magnetic resonance angiography (MRA) with or without a radiopaque contrast agent

To evaluate arteries in people who have had a stroke or a transient ischemic attack or in people who may have an aneurysm or arteriovenous malformation (an abnormal connection between arteries and veins)

Magnetic resonance venography (MRV)

To detect a blood clot in veins of the brain (cerebral venous thrombosis) and to monitor how treatment affects this disorder

Functional magnetic resonance imaging (fMRI)

To identify which areas of the brain are active when a task (such as reading, writing, remembering, calculating, or moving a limb) is done

Perfusion-weighted imaging (PWI) MRI

To estimate how much blood is flowing through a particular area of the brain

Diffusion-weighted imaging (DWI) MRI

To identify very early stroke and to help diagnose Creutzfeld-Jacob disease

Magnetic resonance (MR) spectroscopy

To distinguish between abscesses, tumors, and strokes

Positron emission tomography (PET)

To evaluate blood flow and metabolic activity in the brain

To provide information about seizure disorders

To help identify Alzheimer disease, Parkinson disease, transient ischemic attacks, and strokes

Most often done in research studies