Diagnostic Imaging

A CT scan (also called CAT scan) is short for "computer assisted tomography." It is a valuable diagnostic tool for neurological, orthopedic, heart and vascular specialists. CT scans are more detailed than general X-rays, using computers to generate three-dimensional images from flat, two-dimensional X-ray pictures.

Riverside utilizes the innovative 128-slice CT scanner which provides twice the imaging power and half the radiation of conventional scanners. It is the only locally available 128-slice CT scanner. This technology can produce three-dimensional images within seconds and these images are often compared to slices in a loaf of bread. Doctors can look at each slice individually or combine all slices to see the entire image area.


The cross-sectional CT scan shows bones and soft tissue with more clarity than regular X-rays.

Common uses

CT scans are used in examining injuries to the hands, feet and other skeletal structures because very small bones and surrounding tissues can be seen that aren't easily viewed in an X-ray. CT scans are also used to diagnose cancer, infectious diseases and cardiovascular disease. CT scans are sometimes used in combination with a PET scan.

What to expect when you have a CT scan

Before the test

You should wear comfortable, loose-fitting clothing and may be given a gown to wear during the procedure.

  • You' will be asked to remove your jewelry, hearing aids and eyeglasses because objects with metal may affect the quality of the CT image.
  • If a contrast substance or dye will be used during your exam, you may be asked not to eat or drink anything for several hours before your test.
  • You will be asked about medications, allergies, recent illnesses and your medical history to make sure you don't have a condition that increases the risk of an unusual or adverse reaction to the test or dye.
  • If you are anxious, claustrophobic, or have trouble staying still for any length of time, don't hesitate to talk to your doctor about the possibility of taking a mild sedative you will be prescribed.

The Exam

CT exams are fast, easy and painless. The CT scanner is a large machine with a short tunnel-like hole in the middle where a narrow examination table slides in and out. Scanners and detectors form a ring that rotates around you when you are inside the tunnel. The CT technologist will operate the scanner and monitor your examination from a separate windowed room, but you will always be in two-way communication with the technologist during the entire test.

Here's what will happen:

  • The technologist will position you on the CT examination table.
  • If a contrast substance or dye is used, an IV will be started so the dye can be injected through the IV, or, you may be given a substance to take or drink orally.
  • The correct starting position will be set for the scans and the table will begin to slowly move through the tunnel.
  • As the CT scanner revolves around you, you will hear buzzing, clicking and whirring sounds.
  • The scan takes anywhere from five to 30 minutes.

Following the exam

Unless you were given a sedative, you will be free to go about your usual activities. Your primary care or referring physician will receive a copy of the images and test report and will discuss the results with you.

If you are a Riverside MyChart user, you can view your test results by logging into your MyChart account.