Computed Tomography Scan

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UT Southwestern Medical Center’s computed tomography (CT) services employ the latest imaging technologies to make accurate diagnoses of a wide range of medical conditions, from the simple to the complex.

Our radiology team performs more than 800,000 inpatient and outpatient exams every year. We specialize in advanced technologies and the latest clinical innovations in today’s changing field of medical imaging.

The Latest Tools and Techniques

A computed tomography (CT) scan, sometimes called a CAT scan, uses special X-ray equipment to create detailed images of the body without any surgical exploration.

The X-ray machine rotates around the body and focuses a thin beam of X-ray on the part of the body that is being scanned, generating cross-sectional images of different organs or body parts. The beam moves very rapidly so that multiple images are created from various angles. The computer then analyzes these images and organizes them into a 3-D image.

CT scans can be used to visualize all types of tissue, such as:

  • Blood vessels
  • Bones
  • Organs
  • Soft tissue (such as muscle)

UT Southwestern specialists are highly trained and experienced in conducting and evaluating CT scans. Our services include advanced imaging tools, many of which are not available at other medical facilities.

Conditions We Diagnose With CT Scans

The detailed, cross-sectional insight into the body provided by CT helps doctors diagnose medical conditions such as:

In addition, a CT scan can be used to guide a biopsy or other minimally invasive procedure.

The CT scanner can also create images that help doctors analyze blood flow to various organs, including the brain. For example, a stroke can be diagnosed at an early stage through this procedure.

CT Scans: What to Expect

The CT scan is a fast and patient-friendly exam. Patients should wear comfortable, loose- fitting clothing, such as a sweatshirt without zippers or snaps, to the exam.

If a contrast agent will be used during the exam, the patient will receive instructions to fast for a few hours before the appointment and might need to arrive an hour or two prior to the imaging portion of the scan.

The doctor might also request a blood test prior to the scan.

When checking in, the patient might be asked to change into a gown, depending on the area of the body to be scanned. The patient also will be asked to remove items such as:

  • Hair pins
  • Jewelry
  • Watches

The CT scanner looks like a large donut. The technologist will help the patient lie on a special sliding table that will gently move the patient into position. Then the technologist will go inside a control room to monitor the scan in process. The patient can speak to the technologist at any time using a microphone built into the scanner.

The average scan takes between 10 and 20 minutes, depending on the location of the scan and the information needed. Once it begins, the table will move slowly as the X-ray tube rotates around the patient’s body. The patient will hear a soft clicking or whirring sound as the table moves. It is important that the patient is still during the exam so that the X-rays record an accurate image.

The patient might be asked to wait until the radiologist reviews the images to be sure additional images aren’t needed.

If the patient ingested a contrast medium, it is important that he or she drink plenty of liquid over the 24 to 48 hours following the scan to help pass the medium.

The radiologist will review the images and send a report to the doctor, who will notify the patient of any findings. The patient can also request to receive images on CD.


It is important to note that while the CT scan itself is a painless exam, it does involve exposure to radiation. However, the benefits of an accurate and early diagnosis far outweigh the risk.

Our CT technologist or radiologist can answer any questions a patient might have about a health condition, including pregnancy, that could affect the exam.

Some people have an allergic reaction to contrast media, such as:

  • Hives
  • Itchiness
  • Nausea
  • Shortness of breath
  • Weakness

Report these symptoms to the doctor, radiologist, or imaging technologist immediately. Tell the technologist if the patient has any known allergies to contrast media or iodine, has been diagnosed with heart failure, diabetes, or kidney problems, or has claustrophobia.

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