Computed Axial Tomography (CT)
What is a CT, or CAT, scan?
A CT scan looks inside your body with a special camera. It produces cross-sectional images, like the slices in a loaf of bread. During a CT exam, the scanner takes multiple crosssectional pictures of you. These images are created with the help of a computer and are capable of depicting various internal body parts in much greater detail than standard X-ray pictures. This study greatly enhances the doctor’s ability to diagnose a medical condition.
How does CT work?
The CT scanner contains a large donut-shaped ring that your body slowly passes through on a moveable table. As you pass through the ring, the scanner takes a complete 360-degree picture that is sent to a computer. Then the mechanical table moves a small distance, less than half an inch, positioning you for the next picture. The computer then reconstructs these pictures to form a complete image of your internal anatomy. To make a clearer picture of certain parts of your body, some CT scans require the use of contrast materials, substances that show up as pure white on the X-ray. Contrast materials used include barium, which you usually drink, and iodine, which is usually injected through an IV.
When would I need a CT scan?
A CT scan is most commonly used for cancer detection, to look for abnormal masses that might be malignant tumors. CT scans can show the size and shape of a tumor, its precise location in the body, and whether it is solid or hollow. Sometimes a CT scan can show if a tumor is a benign or malignant, or noncancerous or cancerous. When a needle biopsy is performed for cancer diagnosis, CT scanning can also be used to guide the insertion of the biopsy needle into precisely the right location for sampling a tumor.
In addition to cancer detection, CT scans have many other uses including detecting abscesses, strokes, head injuries, and bleeding inside the skull. It is also used to evaluate trauma patients for internal injuries to the chest and abdomen.
Is the test painful?
The test is completely painless. We will ask you to lie quietly on the CT scanner’s “patient couch” during the study. Because the contrast agents contain iodine, which can cause an allergic reaction in some individuals, be sure to tell the technologist, nurse, or radiologist if you have had an allergic reaction to these agents or if you have any other allergies. You may have been given contrast material as part of a CT scan, kidney X-ray, also called IVP, or heart/blood vessel catheterization, also called an angiogram.
What preparation is required for the test?
We will ask you to change into a hospital gown for some procedures. Metal objects can affect the images, so avoid clothing with zippers and snaps. You may need to remove hairpins, jewelry, eyeglasses, hearing aids, and any removable dental work that could obscure the images. You may also be asked to refrain from eating or drinking anything for 4 hours before the exam. Women should always inform their doctor or X-ray technologist if there is any possibility they are pregnant.
What restrictions or special instructions following the test?
Most patients can return to normal activities immediately following the scan.
When will I receive my test results?
A radiologist, a medical doctor specializing in reading X-rays, will review your scans, generate a report, and send it to your doctor. The technologist performing the exam cannot give you any results. Your doctor should receive a report in 3-4 working days.