Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside of the body.
The cross-sectional images generated during a CT scan can be reformatted in multiple planes, and can even generate three-dimensional images. These images can be viewed on a computer monitor, printed on film or transferred to a CD or DVD.
CT images of internal organs, bones, soft tissue and blood vessels typically provide greater detail than traditional x-rays, particularly of soft tissues and blood vessels.
Using specialized equipment and expertise to create and interpret CT scans of the body, radiologists can more easily diagnose problems such as cancers, cardiovascular disease, infectious disease, appendicitis, trauma and musculoskeletal disorders. Source: RadiologyInfo
What are some of the common uses of the procedure?
- One of the best and fastest tools for examining the chest, abdomen and pelvis because it provides detailed, cross sectional views of all types of tissue.
- Used to determine severe injuries from incidents such as a motor vehicle accident.
- Performed on patients with acute symptoms such as abdominal pain or difficulty breathing.
- Often the best method of detecting many different cancers, including lung, liver, kidney and pancreatic cancer since the image allows a physician to confirm the presence of a tumor and determine its size, precise location and the extent of the tumor’s involvement with other nearby tissue.
- An examination that plays a significant role in the detection, diagnoses and treatment of vascular diseases that can lead to stroke, kidney failure or even death.
How should I prepare for the procedure
You may be asked not to eat or drink anything for a few hours beforehand, especially if a contrast material is going to be used in your exam. You should inform your physician of all medications you are taking and if you have any allergies. If you have a known allergy to contrast material, or “dye”, your doctor may prescribe medication (usually asteroid) to reduce the risk of an allergic reaction. These medications generally need to be taken 12 hours prior to administration of contrast material. To avoid unnecessary delays, contact your doctor before the exact time of your exam. Some medications need to be stopped prior to your exam.
Women should always inform their physician and the CT radiographer if there is any possibility that they may be pregnant. You may be given a gown to wear during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images and should be removed prior to your examination. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing metal underwire. You may be asked to remove any piercings, if possible. You should inform the radiographer if you have a pacemaker device in the upper chest. This is usually not an issue for cardiac CT exams.
The radiographer begins by positioning you on the CT examination table, usually lying flat on your back or less commonly, on your side or on your stomach. Straps and pillows may be used to help you maintain the correct position and to help you remain still during the examination. Depending on the part of the body being scanned, you may be asked to raise your arms over your head. Modern CT scanners are so fast that they can scan through large sections of the body in just a few seconds, and even faster in small children. Reconstruction of data may take a few minutes with report following. For children, the CT scanner technique will be adjusted to their size and the area of interest to reduce the radiation dose. For some CT exams, a contrast material is used to enhance visibility in the area of the body being studied. If contrast material is used, it will be swallowed, injected through an intravenous line (IV) or administered by enema, depending on the type of examination.
The CT examination is usually completed within 30 minutes. The portion requiring intravenous contrast injection usually lasts only 10 to 30 seconds. CT exams are generally painless, fast and easy. Though the scanning itself causes no pain, there may be some discomfort from having to remain still for several minutes and with placement of an IV. If you have a hard time staying still, are very nervous or anxious or have chronic pain, you may find a CT exam to be stressful. If an intravenous contrast material is used, you will feel a pin prick when the needle is inserted into your vein. You will likely have a warm, flushed sensation during the injection of the contrast materials and a metallic taste in your mouth that lasts for at most a minute or two.
When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are properly positioned. With modern CT scanners, you will hear only slight buzzing, clicking and whirring sounds as the CT scanner revolves around you during the imaging process.