CT (CAT) Scan: Head

What Are CT (CAT) Scans?

A computed tomography scan (CT scan), also called computed axial tomography scan (CAT scan), is a type of imaging test. It uses computers and a rotating X-ray machine to take cross-sectional pictures of the body. CT scans give doctors more detailed images than X-rays can provide. Unlike X-rays, they can show organs, soft tissues, and blood vessels in addition to bones.

CT scans are painless. A CT scan involves more exposure to radiation than a regular X-ray does, but the risk is small.

What Is a Head CT Scan?

A CT scan of the head uses a special X-ray machine to take pictures of the brain, skull, and sinuses, as well as blood vessels in the head.

A person getting a CT scan lies on a table. A pillow and sometimes a soft brace will hold their head and neck in place to prevent movement that would result in a blurry image. The donut-shaped machine circles the head, taking pictures to provide cross-sections of the brain from various angles. These pictures are sent to a computer that records the images. It also can put them together to form 3D images.

Why Are Head CT Scans Done?

Doctors may order a head CT scan to:

check for conditions in the brain such as hydrocephalus, swelling, inflammation, bleeding, and signs of injury
check for the presence, location, and size of abscesses, cysts, and tumors
locate birth defects in the brain and skull
look at malformed or injured blood vessels in the head
find the cause of headaches, weakness, or a change in mental status