CT Scan

What is a CT Scan?

CT scans (computed tomography), which are also known as CAT (computerized axial tomography) scans, combine X-ray imaging with computerized image processing to create highly detailed images, “slices” of tissues at different depths in the body.

Doctors may order a CT scan for a variety of diagnostic purposes, such as:

  • Finding areas of internal bleeding or organ damage in patients who have suffered trauma
  • Diagnosing a stroke or identifying its causes
  • Detecting tumors
  • Cancer diagnosis, staging, treatment planning, and treatment monitoring
  • Diagnosing and analyzing complex bone fractures or abnormalities
  • Imaging blood vessels
  • Heart disease screening or diagnosis
  • Interventional-radiology procedures, such as image-guided biopsy or drainage
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CT Screenings for Heart Disease and Lung Cancer

Another important application of CT scans is to screen patients at risk for heart disease or lung cancer for early signs of disease at stages when treatment can be more effective. Available screenings are:

  • CT calcium scoring—looks for signs of coronary artery disease for patients with risk factors for heart disease but no current symptoms
  • CT lung cancer screening—a test for patients with a heavy smoking history but no current lung cancer symptoms, shown to reduce lung cancer mortality by finding disease at an earlier, more treatable stage

You will lie down on a table that will move slowly into the CT scanner. The technologist will help you get into the correct position for the exam, and may use pillows to help you stay still. Depending on the body area the equipment is scanning, the table’s motion may not be noticeable to you. CT scans can take from 5–30 minutes to complete.

Although the technologist will need to go into a control room next to the exam room to perform your scan, you will remain in visual and verbal communication with the technologist at all times. After your scan, you may need to wait on the table while the technologist reviews your images to ensure a quality study.

Learn more

Visit the CT Scan page on RadiologyInfo for more information about CT scans, including details on specific diagnostic purposes and CT scans of different parts of the body.