What Is Cardiac CT?
Cardiac computed tomography (to-MOG-rah-fee), or
cardiac CT, is a painless test that uses an x-ray machine to take clear,
detailed pictures of your heart. It's a common test for showing problems of the
heart. During a cardiac CT scan, the x-ray machine will move around your body
in a circle and take a picture of each part of your heart.
Because an x-ray machine is used, cardiac CT scans
involve radiation. However, the amount of radiation used is small. This test
gives out a radiation dose similar to the amount of radiation you’re
naturally exposed to over 3 years. There is a very small chance that cardiac CT
will cause cancer.
Each picture that the machine takes shows a small
slice of the heart. A computer will put the pictures together to make a large
picture of the whole heart. Sometimes an iodine-based dye is injected into one
of your veins during the scan to help highlight blood vessels and arteries on
the x-ray images.
Cardiac CT is a common test for finding and
- Problems in the heart. Iodine-based dye used with
a cardiac CT scan can show pictures of the coronary arteries. The coronary
arteries are blood vessels on the surface of the heart. If these blood vessels
are narrowed or blocked, you may have chest pain or a
heart attack. The CT scan also can find problems with heart function and
- Problems with the aorta. The aorta is the main
artery that carries oxygen-rich blood from the heart to the body. Cardiac CT
can detect two serious problems in the aorta:
which are diseased areas of a weak blood vessel wall that bulge out. Aneurysms
can be life threatening because they can burst.
- Dissections, which can occur when the layers
of the aortic artery wall peel away from each other. This condition can cause
pain and also may be life threatening.
- Blood clots in the lungs. A cardiac CT scan also
may be used to find a
embolism, a serious but treatable condition. A pulmonary embolism is a
sudden blockage in a lung artery, usually due to a blood clot that traveled to
the lung from the leg.
- Pericardial disease. This is a disease that
occurs in the pericardium, a sac around your heart.
Because the heart is in motion, a fast type of CT
scanner, called multidetector computed tomography (MDCT), is used to show
high-quality pictures of the heart.
Another type of CT scanner, called electron-beam
computed tomography (EBCT), is used to detect calcium in the coronary arteries.
Calcium in the coronary arteries may be an early sign of
artery disease (CAD).
CAD occurs when the coronary arteries (the arteries
that supply blood and oxygen to the heart muscle) harden and narrow due to the
buildup of a material called plaque (plak) on their inner walls. CAD is the
leading cause of death for both men and women in the United States.
Researchers also are studying new ways to use