Houston Methodist. Leading Medicine.
Houston Methodist. Leading Medicine


Computed Tomography (CT) or (CAT)

Patient Information

Appointment Scheduling MSLHImaging@houstonmethodist.org

No appointment necessary for X-Rays. Walk-ins welcome.

Imaging & Diagnostic ServicesMonday - Friday,
7:00 a.m. - 11:00 p.m.
7:00 a.m. - 2:30 p.m.
Breast Center
Monday - Friday,
7:30 a.m. - 6:00 p.m.
8:00 a.m. - 12:00 p.m.


Computed Tomography (CT) or (CAT)

Houston Methodist Sugar Land Hospital is dedicated to providing the safest, most effective imaging for patients on our 64-Slice CT.

We are also happy to offer our CT patients "low dose" software that allows for use of up to 40% less radiation than traditional CT scans. If you would like this technology used during your CT scan, please be sure to request it while scheduling you appointment.

What is a CT or CAT Scan?

A CT or CAT scan is a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles and organs. CT scans are more detailed than general x-rays. In conventional x-rays, a beam of energy is aimed at the body part being studied. A plate behind the body part captures the variations of the energy beam after it passes through the body. While much information can be obtained from a regular x-ray, detailed information about internal organs is not available.

In computed tomography, the x-ray tube moves in a circle around the body. This allows a different view of the organ or structure and provides much greater detail. The x-ray information is sent to a computer that interprets the data and displays it in 2-dimensional form on a monitor. While several images are taken during a CT scan, in many cases, the patient may receive less radiation exposure than with a single standard x-ray.

Why is the Test Done?

CT scans may be performed to aide in a patient’s diagnosis. Tumors, internal bleeding and internal injuries may be better visualized through the use of CT.

What Does “With Contrast” Mean?

CT scans may be done with or without contrast. "Contrast" refers to a liquid substance taken by mouth or injected into an intravenous (IV) line that causes the particular organ or tissue under study to be seen in more detail. Contrast examinations may require you to fast for a certain period of time before the procedure. Your physician or the hospital scheduler will notify you of this prior to your appointment. If you do not have pre-procedure instructions, please call 281-274-7170.

On the Day of Your CT

Where do I go? Campus Map

At the time your appointment is scheduled, you will be instructed to go to the Main Hospital or the Sweetwater Pavilion. When you enter, go to the Information Desk and our staff will gladly direct you from there.

When Should I Arrive?

Arrival times vary based on the type of CT that will be performed. If you are not sure of your time of arrival, please call 281-274-7170 to clarify your arrival time.

How do I Prepare?

Let your physician or the hospital scheduler know if you have ever had a reaction to any contrast dye or if you are allergic to iodine. If you are pregnant or think you may be pregnant, you should notify your physician.

If you are claustrophobic or tend to become anxious easily, tell your physician ahead of time, as he/she may prescribe a mild sedative for you before the procedure to make you more comfortable.

What Will Happen?

CT scans can be performed on an outpatient basis, unless they are part of your inpatient care. Generally, CT scans follow this process:

  1. When the patient arrives for the CT scan, he/she will be asked to remove any clothing, jewelry, or other objects that may interfere with the scan.
  2. If the patient will be having a procedure with IV contrast, an intravenous (IV) line will be started in the arm for injection of the contrast medication. For oral contrast, the patient will be given medication to drink. The duration which you will be asked to drink will be explained by the CT technologist or Imaging Nurse.
  3. The patient lies on a scan table that slides into a large, circular opening of the CT scanner (gantry).
  4. The CT technologist will be in another room where the scanner controls are located. However, the technologist will be in constant sight of the patient through the window. Speakers inside the scanner will enable the staff to communicate with and hear the patient. The patient will be on an open intercom with the technologist in case he/she needs to communicate to the technologist during the procedure.
  5. As the scanner begins to rotate around the patient, low-dose x-rays pass through the body for short amounts of time, and the patient cannot feel this happening.
  6. The x-rays pass through the body's tissues to the detectors and are transmitted to the computer.
  7. The computer transforms the information into an image to be interpreted by the radiologist.
  8. It is very important that the patient remain very still during the procedure.
  9. The technologist will be watching the patient at all times from the control room.
  10. The patient may be asked to wait for a short period of time while the technologist and/or radiologist review the images. If needed, the patient may need to have additional scans performed.

Will it Hurt?

The patient cannot feel the x-ray photons pass through or enter their body. The only discomfort may come from lying on the table, but every effort will be made by the technologist to minimize any discomfort.

Are There Risks?

The scanner does use radiation to obtain the images. The patient’s physician has requested the CT in order to aide in the patient’s care. The ASIR (Adaptive Statistical Iterative Reconstruction) at Houston Methodist Sugar Land Hospital allows for use of less radiation than traditional machines to reduce the amount of radiation the patient is exposed to. Click here to learn more about this scanner.

Before the test begins, the technologist will ask if there is a possibility of pregnancy or allergies, and additional information regarding the patient’s medical history will be reviewed at their appointment time.

After Your Test:

A board certified radiologist will interpret your exam. Legally, the technologist cannot interpret or discuss what they are viewing while performing the exam. Routine reports with the results will be sent to your physician within two to three business days. Please check with your physician’s office to discuss the results.