Cardiac computed tomography, or cardiac CT, is a painless test that uses an X-ray machine and computers to take clear, detailed pictures of the heart. This test is used to look for problems in the heart.
During a cardiac CT scan, an X-ray machine moves around your body in a circle. The machine takes pictures of each part of the heart. A computer assembles the pictures into a 3D image. Contrast material is used to help highlight the area being studied.
What can a cardiac CT scan tell my doctor?
CT scans of internal organs, bones, soft tissue and blood vessels provide greater clarity and show more details than X-ray exams alone.
Previously, a look into the heart came during an invasive heart catheterization for a patient at high risk for heart disease. Now, using the state-of-the-art cardiac CT, thousands of crystal clear images of the heart and its vessels are possible.
Cardiac CT is a common test for finding and evaluating:
- Heart function and heart valves.
- Plaque build up, also known as coronary artery disease, which narrows the arteries and can close off blood flow to the heart, leading to or a heart attack.
- The aorta, the main artery that carries oxygen-rich blood from the heart to the body.
- Aneurysms, diseased areas of a weak blood vessel wall that can burst and be life threatening.
- Dissections, which can occur when the layers of the aortic artery wall peel away from each other.
- Blood clots in the lungs.
- Pulmonary embolism.
- Pericardial disease, disease that occurs in the pericardium, a sac around your heart.
How do I prepare for my exam?
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.
Avoid caffeine and smoking for four hours prior to the exam. You may be asked not to eat a certain number of hours before an exam.
Women should inform their physician and the CT technologist if there is any possibility that they could be pregnant.
How is the test performed?
Patients will receive a contrast material to highlight blood vessels. The contrast will be injected through an IV during the scan.
The technician who operates the cardiac CT scanner or the nurse in the center, will clean areas of the chest and place small sticky patches on those areas. The patches are attached to an EKG (electrocardiogram) machine that records electrical activity of the heart.
Patients lie on a table that enters the CT scanner. Inside the scanner, an X-ray tube moves around the body to take pictures of different parts of your heart. These pictures can be shown on a computer as one large, 3D picture. A technician controls the machine from the next room and can see the patient through a glass window and talk through an intercom to the room.
Patients will be asked to lie still and hold their breath for 10 to 20 seconds. Movement can cause the pictures to blur.
Are there risks?
Because an X-ray machine is used, cardiac CT scans involve radiation. However, the amount of radiation used is small.
How will I find out the results?
A cardiologist will analyze the images and send a report to the primary care physician or the physician who referred you for the exam.
A cardiac CT looks for coronary artery disease which maybe present, regardless of whether the patient is experiencing any symptoms. The amount of calcification as expressed as the calcium score may help to predict the likelihood of a heart attack in the coming years. It also helps doctors decide whether the patient may need to take preventive medicine or take other measures, like changing their diet and increase exercise, to lower the risk of heart attack.