CT Scan

What Is It?

A CT scan, or Computed Axial Tomography scan, is an imaging study which is frequently used in patients who suffer a traumatic brain injury. The general technique can be used to image other parts of the body as well. For example, thoracic CT images the chest, abdominopelvic CT images the organs in the abdominal and pelvic regions. The CT scanner uses x-rays to produce images of the internal parts of the body. It is commonly used to visualize the brain and other structures in the brain but it can be used to image many other body parts as well, as mentioned above.

The CT machine looks like a big doughnut. The patient lies on a table which is moved into the scanner and x-rays are shot through the head from many angles. The resulting data is fed to a computer which reassembles the information into an image that a physician can view on a screen and interpret. While a regular x-ray can only give a general image from one view, at CT gives you "slices" of images through various levels of the body so that you can see the internal structures in closer to 3 dimentions.

A CAT scan is typically quick and painless. However, some types of scans require an IV to be placed to administer intravenous contrast material. Additionally, some CT imaging of other areas of the body may require other things such as a contrast enema to image the intestines better.

For more information about CT scans and their other uses see our CAT Scan page.


Why is CT used so frequently after trauma?

Generally, MRI scans of the brain give a much higher resolution image than a CAT scan. However, they are more expensive and slower to acquire. In addition, some forms of blood are not as easy to interpret.

For these reasons, CT is frequently used after trauma. In a head injured patient, time is critical and these scans are fast, relatively inexpensive and widely available. CT is very good for visualizing acute blood within the head. After trauma the most important pathology that physicians are looking for is significant bleeding and/or swelling in or around the brain. CT allows the quick identification of these findings so that treatment decisions can be made.

In a patient with moderate or severe brain injury, CT's may be ordered frequently throughout their treatment and recovery to evaluate ongoing changes in the brain.



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Important Note: This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.

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