Understanding CAT Scans: How They Work & What to Expect

A CAT scan, also referred to as a CT (computerized tomography) scan, is a three-dimensional X-ray that shows computerized images of internal organs, soft tissue, blood vessels and bones. CT scans show more details than a standard X-ray.

• Traditional CT scanner

Features

• A typical CT scanner has a narrow exam table on which the patient lies and is slid in and out of the CT tunnel. It is non-invasive. The tunnel will rotate around the patient while taking multiple images.

Function

• During the CT scan, X-ray beams and electronic X-ray detectors move around the patient and measure radiation that is absorbed during the scan. The beam goes in a spiral direction.

Significance

• As the X-rays are taken, a computer forms cross-sectional images that are two-dimensional. These are the images the physician will view.

Types

• A standard CT scan only involves the patient lying still and being scanned. A contrast CT consists of either a contrast inserted through an IV or an oral contrast swallowed before the scan.

Considerations

• Most CT scans are done quickly. The patient must remain very still. Claustrophobic patients or those in chronic pain who find it hard to stay still may be offered a sedative before the procedure.