A CT exam uses a special X-ray tube to produce a series of computerized images of your body and is useful in detecting many medical conditions that do not appear on traditional X-rays.
About CT scans
- A CT scanner uses a type of X-ray to create images of the head, bones, organs, blood vessels, and even the heart in extraordinary fine detail. It provides detailed, cross-sectional views of all types of tissue.
- Each X-ray pulse lasts only a fraction of a second, and it takes only a few seconds for the machine to record each slice.
- Patients may need to take a contrast agent orally or intravenously to provide better detail in the images.
What is a CT scan?
A CT scan is also called a computerized axial tomography (CAT) scan. The fast and painless diagnostic tool allows doctors to see inside the body. Physicians use the information they get from a CT scan to rule out or confirm the presence of certain abnormalities, conditions or diseases.
CT uses X-rays in conjunction with advanced computer technology to create accurate detailed images of bones, organs, blood vessels and even your heart, in extraordinarily fine detail. Since Sentara facilities use some of the most advanced multi-slice CTs available, some tests can be performed in mere seconds.
Information from a CT scan can be saved and stored on a computer for further study.
What can a CT scan tell my doctor?
A CT scan is used to:
- Study the head, bones, organs, blood vessels and even the heart in extraordinarily fine detail.
- Diagnose many different cancers, including lung, liver and pancreatic cancer, since the image allows a physician to confirm the presence of a tumor and measure its size, precise location and the extent of the tumor's involvement with other nearby tissue.
- Detect, diagnosis and treat vascular diseases that can lead to stroke, kidney failure or even death.
- Assess for pulmonary embolism (a blood clot in the lung vessels), as well as for abdominal aortic aneurysms.
- Diagnose and treat spinal problems and injuries to the hands, feet and other skeletal structures because it can clearly show even very small bones as well as surrounding tissues such as muscle and blood vessels.
How do I prepare for my exam?
Preparing for a CT scan depends on what part of the body is being examined.
Metal objects, including jewelry, eyeglasses, dentures and hairpins, can cause blemishes on the CT images and should be removed prior to your exam. Depending upon the body part being scanned, you may be asked to remove hearing aids and any removable dental work.
You may be asked to pick up contrast material the day before the exam. You will be given instructions on when to drink it, as well as follow up instructions after the exam. You may be asked not to eat or drink anything before the exam.
Once at the imaging center or hospital, the staff may ask you to change into a hospital gown.
If you are pregnant, think you might be pregnant, or have allergies to iodine, you should inform your doctor and CT tech prior to the exam.
How is the test performed?
A CT is a non-invasive test that might require a contrast agent to be given intravenously and/or orally that will make your blood vessels and tissues more visible. The contrast agent will leave your body naturally within a few hours. If your exam requires a contrast agent, be sure to tell the tech if you have any allergies, especially to iodine or shellfish.
A tech will position a patient for the exam. Once the patient is in place, the table will move quickly through the scanner to determine the correct starting position for the scans. Then, the table will move slowly through the machine as the actual CT scanning is performed.
During your exam, a tech will step into a control room to conduct the actual exam. You may notice a humming or clicking noise coming from the scanner. This is the X-ray tube being activated and rotating around your body.
Patients may be asked to hold their breath at times during the scanning to prevent a blurry image. Any movement might require the exam to be repeated.
A CT exam can take anywhere between 10 and 30 minutes, depending on the area of the body being scanned. There are a few CT procedures that can require a more lengthy appointment. If you have questions about the length of your procedure, please ask your physician.
When the examination is completed, patients will be asked to wait until the tech verifies that the images are of high enough quality for accurate interpretation.
Are there risks?
The CT scan exposes patients to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby. Children should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary.
Patients who have diabetes or renal disease require special care because the kidneys are involved in filtering the contrast through the blood stream. These patients should consult with their physician about proper scheduling of the CT scan.
How will I find out the results?
Your CT scan is supervised and interpreted by a sub-specialized radiologist, a physician specially trained in reading CT scans and other diagnostic images. The radiologist will interpret the findings of your CT and prepare a report for your referring physician. You will receive the results from the physician who sent you for your diagnostic study.