Head/Brain CT

Overview

Computed tomography (CT), sometimes called CAT scan, uses special x-ray equipment to obtain many images from different angles, and then join them together to show a cross-section of body tissues and organs. CT scanning provides more detailed information on head injuries, brain tumors, and other brain diseases than do regular radiographs (plain x-ray films). It also can show bone, soft tissues, and blood vessels in the same images. CT of the head and brain is a patient-friendly exam that involves radiation exposure.

Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant. In some cases an alternate study will be performed to reduce or eliminate the radiation exposure to the fetus.

Equipment

The CT scanner is a large, round machine with a hole in the center, something like a doughnut. The patient lies still on a table that can move up or down, and slide into and out from the center of the hole. Within the machine, an x-ray tube on a rotating gantry (or frame) moves around the patient's body to produce the images, making clicking and whirring noises as the arm moves. Though the technologist will be able to see and speak to you, you will be alone in the room during the exam.

Test Uses

CT of the head can assist in:

• locating skull fractures and brain damage in patients with head injuries.
• detecting a blood clot or bleeding within the brain shortly after a patient exhibits symptoms of a stroke.
• determining the extent of bone and soft tissue damage in patients with facial trauma, and planning surgical reconstruction.
• detecting and localizing bleeding in a patient with sudden severe headache who may have a ruptured or leaking aneurysm.
• detecting some brain tumors.
• diagnosing diseases of the temporal bone on the side of the skull, which may cause hearing problems.
• illuminating enlarged brain cavities (ventricles) in patients with hydrocephalus.
• determining whether inflammation or other changes are present in the paranasal sinuses.
• planning radiation therapy for cancer of the brain or other tissues.
• guiding the passage of a needle used to obtain a tissue sample (biopsy) from the brain.
• non-invasively assessing for aneurysms or arteriovenous malformations through a technique called CT angiography.
• detecting diseases or malformations of the skull.
• three-dimensional imaging of the skull and brain structures.