Computed Tomography (CT)

Using a series of two-dimensional X-ray images, Computed Tomography, also know as CT or CAT scan offers a three-dimensional image of internal organs. Physicians often request a CT scan to diagnose cancers, cardiovascular disease, infectious disease, trauma and musculoskeletal disorders. Creating cross sections-sections of images of bones, blood vessels and soft tissue, a CT scan is the best choice especially because the amount limited risk as compared to the great detail the test provides.

As with most diagnostic tests, notify your physician if you are pregnant or think you could be pregnant before the scheduling your CT scan.

Some tests require a contrast material administered through a vein in your arm. Occasionally, people have mild reactions like a rash. If you have ever had a reaction to contrast material, let your doctor know.

Before the test, you want to avoid eating or drinking for about 2 hours before your CT scan. Leave all valuables at home, including jewelry, and any metal or electronic devices.

Depending on the areas your doctor is imaging, the average CT scan is less than 15 minutes. The scanning is painless, and for most people the buzzing and clicking of the machine as it takes your images is what most people comment on and remember.

Common uses of CT

Because it provides detailed, cross-sectional views of all types of tissue, CT is one of the best tools for studying the chest and abdomen. It is often the preferred method for diagnosing many different cancers, including lung, liver and pancreatic cancer, since the image allows a physician to confirm the presence of a tumor and measure its size, precise location and the extent of the tumor's involvement with other nearby tissue. CT examinations are often used to plan and properly administer radiation treatments for tumors, to guide biopsies and other minimally invasive procedures and to plan surgery and determine surgical respectability. CT can clearly show even very small bones as well as surrounding tissues such as muscle and blood vessels. This makes it invaluable in diagnosing and treating spinal problems and injuries to the hands, feet and other skeletal structures. In cases of trauma CT can quickly identify injuries to the liver, spleen, kidneys or other internal organs. CT can also play a significant role in the detection, diagnosis and treatment of vascular diseases that can lead to stroke, kidney failure or even death.

Baptist M&S Imaging offers low-dose, multi-slice and spiral (helical) CT scanners. This advanced technology enhances patient comfort and allows for faster CT exam than conventional scanners. In addition to being faster, multi-slice and spiral CTs gather continuous data with no gaps between images. Baptist M&S Imaging can help diagnose your condition and get you on the road to recovery.

What to Expect

Your CT technologist will show you the scanner and explain the procedure for your exam. You will be asked to lie down on a padded table. The table will move into the center of the scanner, which is a large machine that has a hole in the center, similar to a doughnut. Once in position, you will be asked to lie as relaxed and still as you can in order to maintain image quality. Your CT technologist will be able to see you and hear you at all times, and will be able to talk to you during the exam. There may be times when the technologist will ask you to hold your breath for a few seconds to ensure that the image is not blurry. You will hear clicking and whirring noises during your scan, but you will not feel anything.

CT contrast

Some CT exams, typically head, brain, neck, chest, abdominal and pelvic procedures, require the use of contrast (an imaging enhancement agent) to improve the visibility of certain tissues or blood vessels. Contrast can be particularly beneficial in creating clear images of the tissue of the liver, spleen, kidneys, or other organs. This agent will be ingested orally, or injected into a vein in your arm (through an IV) where it will enter your blood stream.

Some procedures (abdominal and pelvic CT) will use both oral and IV contrast to ensure an accurate diagnosis.

Intravenous (IV) contrast is used for head, neck, chest, abdominal and pelvic procedures. Baptist M&S Imaging uses only nonionic contrast because it is considered the safest contrast available.

Oral contrast imaging provides information for abdominal and pelvic procedures. Oral contrast is barium-based and once ingested will coat your stomach and intestines. The barium will show up in the imaging, allowing greater visualization. Patients receiving oral contrast are asked to arrive at our center an hour before their CT scan actually begins to allow time for them to drink the contrast agent and have it coat the stomach and intestines.

Please let us know in advance if you have any known allergies, or have ever had an allergic reaction to contrast material.

Required lab values 

For CT studies requiring IV contrast (head, neck, chest, abdominal and pelvic procedures) please notify us if you:

  • Are 50 years or older
  • Are diabetic 
  • Have only one kidney, or known kidney problems
  • Have ever received chemotherapy

Because your safety is a top priority at Baptist M&S Imaging, it is essential that you let us know in advance if you meet any of the above-mentioned criteria. Patients who will be receiving IV contrast and who fit any of the above criteria will need to have their lab values for BUN (blood urea nitrogen) and creatinine drawn and reported to our center PRIOR to their scan to verify that their kidneys are functioning normally. We want to ensure that we can safely perform the exam with no harmful effects to your health. If we do not have these lab values we may not be able to complete your scan as scheduled.

How long will my exam take?

Depending on the type of scan, a CT exam can take between 10 and 45 minutes. When it is complete, you may be asked to wait until the images have been examined to determine if additional images are required. You should plan to be at the center for up to an hour and a half from the time you arrive. If your procedure requires an oral contrast agent, you should expect to be at the center for an hour prior to your study to accommodate the time needed to drink the contrast and have it coat the stomach and intestines. If you are having a CT sinus screen you may only be at the center for 30-45 minutes.

What should I expect once I arrive for my exam?

Please arrive at your confirmed time to register and fill out your insurance and medical information. After you’ve checked in, a registered technologist will show you to a changing room where you may be asked to put on a gown. For your safety and optimal care, the technologist will go over your health history with you.

Do I need to bring anything with me for my CT scan?

YES, please bring with you any previous x-rays, CTs, or MRIs of the body area we will be imaging, or call our office ahead of time to make-arrangements for pick-up from your referring physician’s office. (This is very important because our radiologists use these films as a comparison to your new CT scan for a more accurate diagnosis.)

Please bring your insurance card(s), and policy number or claim authorization, if applicable.

Is advance preparation required? 

Yes, please notify us as soon as possible if: 

  • There is a possibility you may be pregnant
  • You are nursing
  • You weigh more than 400 pounds
  • You have a known allergy or previous adverse reaction to IV contrast
  • You take glyburide (Glucophage®) for control of diabetes
  • You have any known allergies, or have ever had an allergic reaction to contrast material

If your procedure will require a contrast agent to be used, (head, neck, chest, abdominal and pelvic CT) please also let us know if:

  • You are 50 years or older
  • Diabetic
  • Have only one kidney or known kidney problems
  • Or if you have ever received chemotherapy

For patients meeting the above-mentioned criteria, your BUN (blood urea nitrogen) and creatinine levels will be required prior to your study. These values can be obtained through a simple lab blood draw. Please have your doctor’s office arrange for this test, and ask them to forward the results to us, prior to your procedure, or we may not be able to complete your scan as scheduled.

Abdomen and/or pelvis CTs: Please do not eat any food or drink any liquids for at least four hours prior to your exam.

Head or brain, neck and chest CTs: 

  • Please do not eat any food or drink any liquids for at least four hours prior to your exam.
  • Clear liquids (less than eight ounces) are allowed if prescription medications need to be taken.

Preparing for your exam

Wear comfortable clothing without any metal; such as sweat pants. You will lay flat on a table and be asked to remain still as the scanning equipment moves above you down the length of the table. The procedure is very simple and will take between 15 and 20 minutes. As with other medical procedures, if there is a possibility that you are pregnant, please let us know in advance.

When will I receive my exam results?

Your CT exam will produce a series of images, which one of our radiologists will read, looking for any abnormalities. In addition, the radiologist will compare your current exam with any prior exam results to determine any change in structure or shape. Once your results have been analyzed, they will be either phoned or forwarded to your referring physician who will discuss the findings with you. 

Your exam results

One of our board certified radiologists will read and analyze your exam. He will then forward the findings to your referring physician, who will discuss them with you.


  • Baptist M&S Imaging Downtown
  • Baptist M&S Imaging Medical Center
  • Baptist M&S Imaging Mission Trail
  • Baptist M&S Imaging North Central
  • Baptist M&S Imaging Northeast
  • Baptist M&S Imaging Schertz
  • Baptist M&S Imaging Westover Hills