Computed Tomography (CT)
What Is CT Scanning?
A computed tomography scan, also called CT scan or sometimes CAT scan, is a type of imaging that uses a special x-ray machine and powerful computers to generate images of the inside of the body. These images are viewed on a computer screen as highly detailed cross-sectional "slices" of the organs, bones and soft tissues.
At Torrance Memorial Medical Center, our Department of Radiology is equipped with state-of-the-art CT scanners, allowing our physicians to diagnose and stage disease with the highest confidence. CT scans are comfortable and quick, and results are available quickly.
Torrance Memorial is proud that its CT facility has been accredited by the American College of Radiology. To achieve this distinction, the center undergoes continuous, rigorous reviews to demonstrate the highest standards of quality and safety in computed tomography.
What Are The Benefits of a CT Scans?
- A CT scan is painless, non-invasive, and quick to perform.
- CT scanning gives detailed views of many types of tissues, including the lungs, bones, soft tissues and blood vessels.
- CT images can be used to help guide biopsies and offer treatment, often eliminating the need for invasive surgery and surgical biopsy.
What Are The Risk of a CT Scans?
- CT scanning does involve exposure to radiation, although the benefit of an accurate diagnosis typically far outweighs the risk.
- Nursing mothers should wait 24 hours after contrast material injection before resuming breast-feeding.
- Though uncommon, some people can have an adverse reaction to the contrast material.
You should talk to your doctor to learn if there are any other benefits and risks specific to your procedure.
What Will the Exam Be Like?
You will lie comfortably on the motorized CT exam table. Pillows will be placed under or around you to help keep you still in the proper position. The table will move slowly into the CT scanner. You will be alone in the room, but the radiologist or technologist can see you and will be in constant communication with you through speakers in the room. The x-ray machine often makes whirring sounds as it moves around and captures pictures. Patients rarely experience claustrophobia with this type of exam, due to both the design of the scanner and the ultra-fast exam times.
Depending on the type of the exam your doctor has requested, the technologist may give you a material called a contrast agent (or "dye") that makes it easier to see certain tissues or blood vessels. The contrast material may be swallowed, injected into the bloodstream, or administered by enema.
If intravenous contrast material is used, a technologist or radiology nurse will ask you whether you have any allergies, especially to medication or iodine, and whether you have a history of diabetes, asthma, a heart condition, kidney or thyroid problems. These conditions may give you a higher chance of reacting to the contrast material or having problems eliminating the material from your body after the exam.
You may be asked to drink a liquid contrast material, especially if the radiologist needs to see the stomach, small bowel, and colon. Most commonly the CT exam is performed 1-2 hours after you have finished drinking the contrast to allow time for it to fill your intestines before the pictures are taken.
In some circumstances your doctor may request that contrast material be given by enema to better evaluate the colon. As the contrast material goes into your colon, you may feel full and have some cramping or a desire to empty your bowel. These are very common sensations, and most people tolerate the exam well.
Most often, the contrast material is injected through a vein in your arm. You will feel a minor pinch or sting with the injection, and you may feel flushed and warm or even have a metallic taste in your mouth. These are normal reactions to contrast material and won't last more than a minute or two. Occasionally, some people feel a slight itching sensation. If it lasts or if hives develop, you may be given a medicine to relieve the itch. Very rarely, difficulty breathing or swelling in the throat or other parts of the body can happen. If you experience these symptoms, tell the radiologist or technologist immediately.
The contrast material will be naturally eliminated from your body within a few hours to a day or two depending on the area examined and the type of contrast material used.
A CT exam in one of Torrance Memorial's state-of-the-art scanners typically takes less than 5 minutes depending on the type of exam ordered.
What Does the Equipment Look Like?
A CT scanner is a large, square machine with a hole in the center. It has a motorized exam table attached that can be moved up and down or forward and backward through the opening. Hidden inside the machine is an X-ray tube that moves around your body to capture the images.
How Should I Prepare for the Exam?
- Wear comfortable, loose-fitting clothing for your exam. Metal objects can affect the images, so avoid wearing clothing with zippers and snaps.
- You will be asked to remove anything metallic that might affect the quality of the images, including hairpins, jewelry, eyeglasses, hearing aids and any removable dental work.
- For some CT scans your doctor may instruct you not to eat or drink for one or more hours before your exam.
- Inform your doctor of any allergies you have to foods or medications, and especially to iodine.
- Inform your doctor of any recent illnesses or medical conditions.
- Always inform your doctor and the technologist if you are pregnant or think there is a possibility you may be pregnant.
How Will You Learn About Your Results?
The technologist will not give you the test results directly, as the images still need to be reviewed by a radiologist. After reviewing the study, the radiologist will send an official report to your physician, who can then discuss the results with you.