What Does a CT Head Scan Show?

Medically Reviewed on 1/29/2021

A CT head scan takes detailed X-rays at different angles of the head and brain to identify conditions such as brain tumors, aneurysms, and others.
A CT head scan takes detailed X-rays at different angles of the head and brain to identify conditions such as brain tumors, aneurysms, and others.

A computerized axial tomography (CAT) or computerized tomography (CT) scan uses a series of X-rays taken at different angles to produce a detailed image of the head and brain. 

The process of taking a CT scan of the head begins by taking many different X-ray views at various angles. These views are then combined using computer processing to create cross-sectional images, including the tissues inside of a solid organ. 

A CT scan is done to study the patient’s skull, brain, jaw, sinuses, and facial bones. A doctor may recommend a head CT scan if a patient has any of the following symptoms:

This scan can also help to rule out other causes of headache that present symptoms like a migraine.

CT head scans are used for

  • Investigating certain cancers or tumors of the skull, brain, and coverings over the brain.
  • Identifying the location of tumors, stage of cancer, and site to perform a biopsy.
  • Identifying congenital defects of the skull.
  • Identifying hydrocephalus or bulging of the skull because of high pressure.
  • Guiding doctors or surgeons during a procedure, such as a biopsy.
  • Helping plan for certain types of therapy and surgery, as well as determining whether your body is responding to treatment.
  • Detecting cysts or infections in the brain and identifying the bone structures within the skull.
  • Quickly inspecting a patient after an accident to identify traumatic head injuries or any other internal injuries.
  • Checking if the patient is displaying symptoms, such as 
  • Diagnosing conditions such as 
    • abnormal blood vessels, 
    • aneurysms, 
    • bone infection, 
    • brain damage,
    • brain swelling, 
    • brain tumors, or 
    • stroke.

Special CT scans:

  • They are done to study the paranasal sinuses. These are useful if sinusitis is suspected.
  • A typical series of CT scans for the sinuses use less X-ray radiation than a standard complete set of X-rays. However, a CT scan of the sinuses does not show any brain tissues. Most CT scans of the head do not include all the sinuses.
  • A CT scan with contrast may be ordered for people with strokes, hydrocephalus, or certain growths. These structures are better differentiated in a contrast CT scan.

CT scan side effects:

  • CT scans use low levels of ionizing radiation. The risk of exposure to ionizing radiation, although small, is present. Any radiation is theoretically dangerous for body cells.
  • On rare occasions, the contrast medium used for CT scans may cause an allergic reaction. The reaction may be severe enough in some people to cause kidney damage or even death.

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Medically Reviewed on 1/29/2021
WebMD. CT Scans for Headache and Migraine Diagnosis. https://www.webmd.com/migraines-headaches/making-diagnosis-ct-scan