Department of Radiology

at Brigham and Women's Faulkner Hospital

Computed Tomography (CT)

Computed tomography is commonly referred to as CT or a CAT scan. It combines an X-ray with a computer to produce very detailed images of the body. CT is used to help diagnose and treat medical conditions related to internal organs, soft tissue, bones and blood vessels. The images from a CT scan are “cross-sections” of your body, like looking at one slice from a loaf of bread.

Types of CT Exams:

  • CT scan of the chest
  • CT scan of the abdomen and pelvis
  • CT urogram
  • CT colonography (virtual colonoscopy)
  • CT angiography
  • CT scan of the head
  • CT scan of the paranasal sinuses
  • CT scan of the musculoskeletal system and joints
  • CT guided procedures: Biopsy, insertion of a catheter
  • Lung Cancer Screening

Frequently Asked Questions About Computed Tomography

How do I prepare for my CT scan?

The type of CT scan you are having determines if you need special preparation. Some CT exams require an injection of an “X-ray dye” called contrast media. If contrast media is used you should not eat or drink anything except clear fluid for four hours before your scan. You should tell your doctor about any medications you are taking and if you have allergies. If you need an injection of contrast media, it may be necessary to obtain blood work first. Kidney function is very important to the radiologist and the CT technologist. Please contact your physician and find out if blood work is needed before your CT study. If you have had recent blood work outside of the Partners HealthCare network, please make sure you bring a copy for the technologist. Be sure to bring a current list of medications.

If you are having a CT scan of the abdomen or pelvis you may have to drink a barium mixture before the exam and you will be asked to check in about one hour before your appointment. You should not eat for at least four hours before this exam. The barium drink allows better images of the stomach and intestines. The barium also helps the radiologist see the difference between bowels, organs and vessels. If you cannot drink the entire amount of barium or become uncomfortable, please let the staff know.

Women who are or think they may be pregnant should always consult with their doctor before a scan. If you are or think you may be pregnant, please let the CT technologist know ahead of time to ensure proper precautions are taken.

Who is performing my CT scan?

A CT technologist will greet you after you have checked into the Radiology Department. You will be asked to complete a screening form if you are receiving an IV or oral contrast. The screening form provides information for your safety. It also assists the radiologist in the best scanning option for the best diagnosis. The screening form will need to be completed upon each CT exam return where IV or oral contrast is required.

All CT technologists at Brigham and Women’s Faulkner Hospital have passed a certification exam in CT given by the American Registry of Radiologic Technologists. The technologist will perform the CT scan and answer any questions you may have.

Your completed exam will be read by a board certified radiologist. A radiologist is a physician trained to diagnose conditions seen on medical imaging studies. The radiologist will send the report to your ordering provider.

What should I expect when having a CT scan?

During a CT scan you will lay on a table on your back or front, head or feet first, depending on the exam. Once you are positioned correctly, the technologist will step into a control room and start the scan. The table will move slowly through the CT scanner opening as images are taken. You may be told to “hold still” or “hold your breath.” This is only for a short amount of time (typically less than 10 seconds) while a series of pictures are taken. Once you are properly positioned on the CT scan table the CT scans usually take no longer than 10 to 20 seconds depending on the body part(s) being scanned.

If contrast material is needed one of the technologists trained in IV insertion will insert an IV for the contrast injection. Contrast allows a better look at your blood vessels and internal organs. You might feel a warm sensation as the contrast agent is injected. If you are scheduled for this type of exam, the technologist will review your medical history before the exam. The technologist will also review any potential side effects.

Once the scan is complete the technologist will come into the exam room and remove the IV if one has been placed. The technologist will make sure you are not experiencing complications. If further instructions are needed, the technologist will give them to you before you leave.

Is CT safe?

The benefits of CT are extraordinary in helping to diagnose or rule out conditions. CT is considered safe, but there are some things to know. CT uses radiation to produce images. At Brigham and Women’s Faulkner Hospital, we use state-of-the-art technology to minimize radiation dose. We also screen all patients for allergies and other conditions if they are receiving an intravenous contrast injection. You can be assured that the benefit of performing a CT scan outweighs the minimal risk of radiation exposure or contrast injection.

All CT exam requests are reviewed by a radiologist beforehand. Instructions are given to the technologists on how to perform the exam after the benefits and risks have been reviewed by the radiologist. Patients should inform staff if they are pregnant, or have allergies or impaired kidney function. The technologist or radiologist will answer any questions you may have at the time of your appointment.

When should I expect to have the results of a CT scan?

Results for your exam are generally available for your provider to view on the same day of your exam. CT exams are interpreted by a board certified radiologist and a detailed report will be sent to your ordering provider. 

Appointments are available Monday through Friday from 7 am to 8 pm. Saturday and Sunday appointments are available from 8:00 am to 5:15 pm.


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