CT Head/Brain Perfusion and CT Angiogram Head — Without or With IV Contrast

What is this test?

This is a group of CT examinations involving the head and brain. A routine head CT shows the brain's structure, brain perfusion CT estimates regional blood flow, and CT angiography of the head shows the arteries and other blood vessels. The examination may be ordered without contrast or with IV iodinated contrast, depending on the clinical question.

Why might I need this test?

These scans may be used to evaluate sudden neurologic symptoms, suspected stroke, severe headache, head injury, abnormal bleeding, seizures, or other conditions affecting the brain. Brain perfusion and angiographic images can help clinicians identify reduced blood flow, blocked or narrowed vessels, bleeding, or other abnormalities.

How is the test performed?

You lie on a CT table while an X-ray scanner takes several images of your head. If IV contrast is used, a needle is placed in a vein to deliver the contrast. The scan is generally quick, and a radiologist reviews the images and sends the report to your ordering clinician.

How do I prepare for the test?

There is usually no special preparation for a head CT. If IV contrast is planned, tell the imaging staff about any prior contrast reaction, kidney disease, or allergy to iodinated contrast and follow the facility's instructions. For urgent imaging, treatment takes priority over delaying the scan for preparation.