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CT Scan

What Is a CT Scan?
Routine body computed tomography (CT) is commonly indicated to characterize abnormalities identified on other radiology tests, diagnose and follow the therapeutic response of tumors, and evaluate chronic or unusual symptoms for which no other cause has been found.

Examinations may include some or all of the chest, abdomen, and pelvis. Many CT examinations require the administration of intravenous iodine contrast material; most abdominal and pelvic CT studies require patients to drink contrast material to fill out the bowel.

In addition to routine imaging, our state-of-the-art multidetector helical CT scanners allow us to perform a wide range of more complex examinations, such as multiphase studies of the liver, kidneys, or pancreas; High-Resolution CT of the chest (HRCT); and CT angiography, where a well-timed intravenous contrast injection is used to evaluate the blood vessels in the chest, abdomen, or pelvis.

New and investigational studies available in the near future include coronary calcium scoring to evaluate heart disease risk, low-dose lung cancer screening, and virtual CT colonoscopy to screen for colon cancer.

What Will The Exam Be Like?
You will meet your CT technologist whose primary concern is your care and well-being.

Prior to the start of your CT exam, the technologist will explain the procedure to you. This is done for two reasons: to solicit your cooperation and to put your mind at ease as to what is taking place.

Next, you will be gently positioned and secured on the scan table. It is important that you be secured, because even the slightest movement during the split seconds of imaging can blur the picture and result in the need for repeated scans.

Then, you will be moved into the scanner, which is a small, air-conditioned chamber. The technologist will have you in full view at all times and be in constant communication via two-way microphones. During this brief time, you will hear the humming of the equipment as it produces the images. You may also feel slight movement of the table as it prepares for the next scan.

A contrast media may be required. This is usually given by injection. It is normal to feel a warm sensation as the dye makes its way through your body. This substance is given to highlight various body parts and is eliminated in a day or two.

How Long Does The Exam Take?
The exam usually takes 45 minutes. This allows for preparation, as well as time for the computer to generate the image. Actual exposure time is minimal. Time may vary significantly depending on the nature of the study and other factors.

How Will I Learn The Results?
The radiologist, a physician specialist in imaging, will evaluate your exam and discuss them with your doctor, who will then consult with you.

What should I remember when preparing for a CT Scan?
Tell your doctor or technologist, if you are:

  • Pregnant or think you may be.
  • Allergic to iodine or other materials.
  • Undergoing radiation therapy.

You should also:

  • Wear comfortable clothing
  • Avoid wearing jewelry - metals may interfere with the accuracy of the film image.
  • Be sure to ask any questions relating to your examination.

For more information, contact the Evanston Northwestern Healthcare Departments of Radiology at:

Evanston Hospital 847.570.2469
Glenbrook Hospital 847.657.5861
Highland Park Hospital 847.480.3743