Computerized Tomography - CTA's
What is CT Angiography?
CT (computed tomography) angiography (CTA) is an examination that uses x-rays to visualize blood flow in arterial and venous vessels throughout the body, from arteries serving the brain to those bringing blood to the lungs, kidneys, and arms and legs. CT combines the use of x-rays with computerized analysis of the images. Beams of x-rays are passed from a rotating device through the area of interest in the patient's body from several different angles to create cross-sectional images, which then are assembled by computer into a three-dimensional picture of the area being studied. Compared to catheter angiography, which involves placing a sizable catheter and injecting contrast material into a large artery or vein, CTA is a much less invasive and more patient-friendly procedure. Contrast material is injected into a small peripheral vein by using a small needle or catheter. This type of exam has been used to screen large numbers of individuals for arterial disease. Most patients undergo CT angiography without being admitted to a hospital.
How should I prepare for this procedure?
Depending on the part of the body to be examined, you may be asked to take only clear liquids by mouth before CTA. You will be asked whether you have asthma or any allergies to foods or drugs, and what medications you are currently taking. If you are pregnant you should inform the technologist before the procedure.
How does the procedure work?
Before the actual exam begins you will be injected with a dose of contrast material to make your blood vessels stand out. An auto injector machine is used that controls the timing and rate of injection. During the exam the rotating device spins around the patient, creating a fan shaped beam of x-rays and the detector takes snapshots of the beam after it passes through the patient.
What will I experience during the procedure?
CTA takes about 10-25 minutes from the time the actual examination begins. You can expect to be in or near the examination room for 20-60 minutes. You may feel warm all over when the contrast material is injected, but you shouldn’t feel any pain. You will be asked to remain still during the exam. The examination table will move in and out of the scanner opening, but it is not enclosed and only one small portion of your body will be inside the machine at any time. You may be asked to hold your breath for 10-25 seconds to be sure the images will not be blurred. Family members are not allowed into the exam room. You can eat right after your procedure is completed and you should drink plenty of fluids to flush out the remaining contrast from your system.
What is Coronary Angiogram?
Coronary angiogram is performed to find out if your coronary arteries are clogged, where and by how much. You may be given medicine to relax you prior to the exam. Through an IV, iodine will be injected into your veins to help the technologist visualize the arteries. Many pictures are taken and you will be asked to hold your breath several times. A 3-D reconstruction will also be completed on you. By studying the 3-D reconstruction and the pictures the doctor will be able to see any problems with your coronary arteries.