Computed Tomography
Computed tomography (CT) or CAT scan is a diagnostic imaging test that uses computer technology and a series of X-rays to create detailed images of internal organs, bones, soft tissue and blood vessels. The cross-sectional images generated during a CT scan can be reformatted in multiple planes, and can even generate three-dimensional images which can be viewed on a computer monitor. CT scans provide more detailed information than traditional X-rays.
CT is fast, painless, noninvasive and accurate. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives.
Why CT is Used
In order for the physician to better understand your condition, he or she may suggest a CT scan to help:
- Diagnose muscle or bone disorders
- Pinpoint the location of a tumor, infection or blood clot
- Guide procedures such as surgery, biopsy and radiation therapy
- Detect and monitor diseases such as cancer or heart disease
- Detect internal injuries and bleeding
Preparing for an Exam
How you prepare for a CT exam depends on which part of your body is being scanned. You may be asked to remove your clothing and wear a hospital gown. You’ll need to remove any metal objects such as jewelry, eyeglasses, hearing aids, removable dental work or piercings that might interfere with image quality.
Contrast material
Some CT scans require the use of contrast material to enhance the visualization of body tissues, organs and vessels. The contrast material blocks X-rays and appears white on images, which can help emphasize blood vessels, bowel or other structures. You may be asked to fast for a period of time if your exam requires contrast. Contrast material can enter your body in a variety of ways.
Oral
If your esophagus, stomach or intestinal tract is being scanned you may need to drink a liquid that contains contrast material. This is usually 2-3 hours before your exam.
Injection
IV Contrast can be injected into an intravenous line to help view your bowel, urinary tract, organs or blood vessels. You will probably experience a warm, flushed feeling during the injection. A metallic taste in your mouth or a sensation like you have to urinate is not uncommon. This is an effect of the contrast and will subside quickly.
Safety
Some contrast material contains iodine. Be certain to inform your physician if you have ever had an adverse reaction to iodinated contrast material before the day of the exam.
During a CT scan, you’re briefly exposed to radiation. Radiation exposure may increase your risk of developing cancer, however, the risk is so small it cannot be reliably measured. Doctors and scientists believe CT scans provide enough valuable information to outweigh their potential risks. Be sure to inform your doctor if you’re pregnant. They may recommend another type of exam, such as ultrasound or magnetic resonance imaging (MRI), to avoid the risk of exposing your fetus to the radiation.
