CT scan
Computed tomography (CT) is an imaging method that
uses x-rays to create cross-sectional pictures of the body. Our
16-slice and 64-slice CT scanners provide superior image quality at
remarkable speed. A CT scan that used to take three minutes can now
take about 20 seconds or less. These shorter scan times allow for a
more comfortable patient experience.
CAT scan; Computed axial tomography (CAT) scanCT rapidly creates detailed pictures of the body, including the brain, chest, and abdomen. The test may be used to:
- Study blood vessels
- Identify masses and tumors, including cancer
- Guide a surgeon to the right area during a biopsy
You will be asked to
lie on a narrow table that slides into the center of the CT scanner.
Depending on the study being done, you may need to lie on your stomach,
back, or side.
Once inside the scanner, the machine's x-ray beam
rotates around you. (Modern "spiral" scanners can perform the exam in
one continuous motion.)
Small detectors inside the scanner
measure the amount of x-rays that make it through the part of the body
being studied. A computer takes this information and uses it to create
several individual images, called slices. These images can be stored,
viewed on a monitor, or printed on film. Three-dimensional models of
organs can be created by stacking the individual slices together.
You
must be still during the exam, because movement causes blurred images.
You may be told to hold your breath for short periods of time.
Generally,
complete scans take only a few minutes. The newest multidetector
scanners can image your entire body, head to toe, in less than 30
seconds.
Certain
exams require a special dye, called contrast, to be delivered into the
body before the test starts. Contrast can highlight specific areas
inside the body, which creates a clearer image.
Contrast may be
delivered using an intravenous line (IV) that is placed in a vein in
your hand or forearm. Contrast may also be given through the rectum
using an enema, or as a liquid that you drink before the scan. (When
you actually drink the contrast depends on the type of exam being
done.) The contrast liquid may taste chalky, although some are flavored
to make it taste a little better. The contrast eventually passes out of
your body through your stools.
If contrast is used, you may also be asked not to eat or drink anything for 4-6 hours before the test.
If
you weigh more than 300 pounds, have your doctor contact the scanner
operator before the exam. CT scanners have a weight limit. Too much
weight can cause damage to the scanner's working parts.
Since
x-rays have difficulty passing through metal, you will be asked to
remove jewelry and wear a hospital gown during the study.
The x-rays are painless. Some people may have discomfort from lying on the hard table.
Contrast
give through an IV may cause a slight burning sensation, a metallic
taste in the mouth, and a warm flushing of the body. These sensations
are normal and usually go away within a few seconds.
Review Date: 10/23/2006
Reviewed By: Stuart Bentley-Hibbert, M.D., Ph.D., Department of Radiology, Weill Cornell Medical Center, New York, NY. Review provided by VeriMed Healthcare Network.
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