Computed Tomography (CT) Services

What is Computed Axial Tomography (CT)?

CT scanning—sometimes called CAT scanning—is a noninvasive medical test that helps physicians diagnose and treat medical conditions.

CT imaging combines special x-ray equipment with sophisticated computers to produce multiple images or pictures of the inside of the body. These cross-sectional images of the area being studied can then be examined on a computer monitor or printed.

seal: Computed Tomography, American College of Radiology Accredited Facility

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity and reveal more details than regular x-ray exams.

Using specialized equipment and expertise to create and interpret CT scans of the body, radiologists can more easily diagnose problems such as cancers, cardiovascular disease, infectious disease, trauma and musculoskeletal disorders.

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CT Scan

CT scans are better than conventional X-ray examinations for showing bone, soft tissue and blood vessels.

How Should I Prepare?

This is required within 30 days prior to the CT examination for the following people:

If you have this test done at an outside facility, it is your responsibility to obtain a copy of the result and bring it to the appointment with you.

CONTRAST MATERIAL (helps your body part show up better in the pictures):  If you need contrast material for your CT examination, it will be given to you by mouth (oral contrast) or through your vein (intravenously (IV)). You should inform your caregiver of any medications you are taking, and if you have any allergies, especially to contrast materials. If you have a history of contrast reaction, your ordering physician is responsible for prescribing the premedication for you. The American College of Radiology recommends the following premedication:

Oral (Drinkable) Contrast Material or Intravenous Contrast Material: You may need to drink a liquid that may be either water- or barium-based if you are having an abdominal or pelvic CT scan. Depending upon your type of examination, you may have to come early to the Department or imaging center in order for the oral contrast agent to pass from the stomach into the small intestine.

There are two different chemical compositions for oral contrast that we use in the Radiology Department at Stanford. These include thin solutions of barium and water-based contrast agents.

There will be specific  instructions related to the ingestion of water-based contrast agents for these three separate examinations, so please read the instructions carefully and be sure to come to the Department with sufficient time to drink the contrast material required.

Intravenous (IV) Contrast Liquid: You may be given the contrast material in an intravenous (IV) tube that is put into your vein. When the contrast material is put into your vein, you may feel warm or flushed. You may have a metal or salty taste in your mouth or you may feel sick to your stomach. Tell your caregiver if you feel like you are going to vomit (throw up). This only lasts 1 to 2 minutes. People who have had an allergic reaction to contrast material may be allergic to this contrast material. Caregivers will take special precautions for your safety if you have these allergies. Nursing mothers should wait for 24 hours after contrast material injection before resuming breastfeeding.

Diabetic Patients: If you are a diabetic patient taking any medication that contains Metformin (Glucophage, Glucovance, Metglip, Fortamet, Riomet, Avandamet) and are scheduled for an examination that requires IV contrast (CT, IVP, or Arthrogram), DO NOT take your medication the day of the examination and for 48 hours after. You MUST follow up with your physician for a blood test and instructions on when to resume this medication.

Do not eat for 2.5 hours prior to the examination. You may have clear liquids up to two hours before the examination. Clear liquids include water, black coffee or tea, apple juice, clear soda, or clear broth. You may take your medication at your normal time with water. Follow any other special instructions from your caregiver.

Do not wear any jewelry including rings, earrings, necklaces, or watches. Wear comfortable clothing without metal zippers or snaps. Remove anything that might interfere with the CT scan pictures such as eyeglasses, dentures, or hairpins. You may also be asked to remove hearing aids and removable dental work.

You have the right to help plan your care. To help with this plan, you must learn about your health condition and how it may be treated. You can then discuss treatment options with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.

YOU MUST CHECK IN TO REGISTER 30 MINUTES PRIOR TO THE APPOINTMENT TIME IF YOUR APPOINTMENT IS MONDAY–FRIDAY BETWEEN THE HOURS OF 7:00am AND 5:30pm . If your appointment is outside these hours at the Blake Wilbur Clinic, please report directly to the clinic 30 minutes prior to the appointment time.


Bring a family member or friend with you if you need to wait for examination results. They can help support you during and after the examination. They can also drive you home if you have sedative medicine during the examination. If you do take sedative medication, you cannot drive yourself.

This is a room where your family can wait until your CT scan is done. If your family leaves, ask them to leave a phone number where they can be reached. When it is time for you to go home, someone will need to drive you home if you had sedative medicine. Do not drive home alone.

PLEASE CALL (650) 723-6855 IF:

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