A computed tomography (CT) scan with contrast allows a doctor to better see particular areas inside the body. Sometimes called a computed axial tomography (CAT) scan, a CT scan uses x-rays to provide cumulative views of bodily structures from multiple angles. Contrast material is a dye that highlights specific organs or tissues during the CT process and makes those structures easier for doctors to see on the images that result.
CT scanners are vital diagnostic tools in the hands of medical professionals. Using a CT scan with contrast, a doctor can examine all parts inside a patient's body for signs of disease. The cross-sectional images that result from a scan facilitate early detection of tumors, abscesses, abnormal blood flow, and signs of many other serious conditions so that these illnesses can be treated in a timely manner.
One of the most commonly used materials in CT scan with contrast is iodine dye. Other contrast materials include gastrografin, barium, and barium sulfate, any of which can be given as oral, rectal, or intravenous (IV) contrast. Patients who must undergo CT scan with contrast may be required by their doctors not to eat solid food for four to six hours prior to the scan. If a person is allergic to the contrast material, he or she might need special medications before the scan in order to safely undergo the procedure.
Injected dye, given through a vein in the patient's hand or forearm, is used to highlight blood vessels or major organs and structures like the brain, the spine, or the liver. The dye is sometimes injected directly into a site that a doctor wants to study, such as the knee or elbow joint. In oral administration of contrast, often used for abdominal scans, the patient is required to drink the contrast material before his or her CT scan. The time interval between drinking the contrast material and undergoing the CT scan varies, and the interval depends on which part of the body the doctor wants to examine. Rectal administration, accomplished through an enema, is used when doctors need to study the large intestine.
Side effects of a CT scan with contrast may include blood clots, dizziness, nausea, and hives. Patients who have multiple scans might, over time, develop an allergy to the contrast material. Anyone who has experienced adverse effects as a result of a previous CT scan should tell his or her doctor before undergoing a subsequent procedure. Prior to a CT scan with contrast, patients should inform their doctors of all medications they are taking and any medical conditions for which they are being treated.