Cardiac CT Angiography
Computed tomography (CT) is a noninvasive imaging technology that provides detailed pictures of organs and tissues inside the body. Cardiac CT angiography imaging focuses on the heart and its surrounding blood vessels. Physicians use these images to help diagnose coronary artery disease, or heart artery blockages, and to estimate your future risk of having a heart attack. Cardiac CT can help doctors treat heart disease and determine if current treatments are effective. In some cases, CT angiography may prevent the need for more invasive tests.
256-Slice CT: Faster Scan Provides Many Benefits
At the University of Chicago Medicine, our cardiologists use a highly advanced 256-slice CT machine for all heart CT scans. We're the first--and only--hospital in Illinois to offer this powerful imaging technology that provides sharp, 3-dimensional images of the heart.
With this scanner, doctors can view the heart and its coronary arteries from any angle. These images can lead to a completely noninvasive diagnosis and even risk assessment for coronary artery disease. A November 2008 study published in the New England Journal of Medicine found that CT angiography is accurate in identifying blockages and narrowing of arteries and in characterizing disease severity in patients with symptoms. The study focused on the use of 64-slice CT technology, a precursor to the 256-slice machine in use at the University of Chicago.
The remarkably fast 256-slice CT machine produces scans in approximately five seconds. The new scanner reduces the radiation exposure by as much as 80 percent compared to some scans performed on the standard 64-slice CT exams. The speed of the scanner makes the process easier for patients who may have difficulty holding their breath during a scan. The machine is fast enough to get motionless pictures of the heart despite heart rates of up to 100 beats per minute.
A 256-slice heart scan requires no sedation or recovery time. A dye called a contrast agent is typically given through an IV during the scan. This dye allows physicians to follow blood flow as it travels through blood vessels and the heart.
When is Cardiac CT Used?
Cardiac CT angiography is helpful in assessing a wide range of heart conditions, including coronary artery disease, diseases of the aorta and other structural heart problems. It is particularly helpful in patients who have had an inconclusive stress test, but it may also be used to help surgeons, interventional cardiologists, and electrophysiologists to plan and perform complex heart procedures.
At the University of Chicago Medicine, our team of cardiac imaging experts is highly skilled at determining which heart tests are appropriate for each patient. Cardiac CT angiography is just one of the many valuable tests available to evaluate heart disease. Some instances when cardiac CT may be recommended include the following:
- Chest pain and/or suspected coronary artery disease. Cardiac CT angiography can be used as a noninvasive way to determine if chest pain is due to the blockages or narrowing of the coronary arteries. This is in contrast to a conventional catheter-based angiogram, a more invasive procedure that involves threading a catheter into blood vessels. CT angiography can help rule out the need for a catheter-based angiogram, but it does not replace the need for a catheter angiogram in all cases.
Data gathered from the CT exam helps cardiologists determine if a patient may need cholesterol-lowering drugs called statins, and if other medicines or lifestyle changes are recommended to reduce the risk for heart attack or stroke.
- Inconclusive stress test. If data gathered from a stress test is inconclusive, physicians may recommend a cardiac CT to look for coronary artery disease or other problems.
- Presence of other heart disease symptoms. Like the symptom of chest pain, people who exhibit other symptoms of heart disease, such as shortness of breath, neck, jaw, back or arm pain may be candidates for CT angiography.
CT angiography is not recommended as a screening tool for heart disease, however, a similar test, called a coronary calcium scan, can be used as a screening tool for coronary artery disease (see below). As with many types of heart tests and procedures, there are risks associated with CT angiography, such as exposure to radiation and a low risk for a reaction to the contrast dye. In addition to producing lower levels of radiation than previous CT machines, the 256-slice CT scan often requires less contrast dye than slower machines.
Cardiac CT for Calcium Scoring: Screening for Coronary Artery Disease
Coronary calcium scanning from which a coronary calcium score can be computed is a test that uses a multi-slice CT machine to detect calcified plaque build-up in the coronary arteries. Where there is an abundance of calcified plaque there is often non-calcified plaque as well which may be composed of cholesterol, scar tissue, and other substances. Coronary artery plaque -- whether calcified or not -- indicates the presence of coronary artery disease, and is the single most important risk factor for heart attack.
Physicians use the CT machine to measure the amount of calcium deposits to determine a calcium score. A high calcium score could indicate the need for more aggressive treatment in some people. For others, it may indicate a lower than expected risk of future heart attack. Unlike CT angiography, cardiac CT for calcium scoring requires no IV or contrast agent. The test takes only a few seconds to complete.
It's important to note that cardiologists can categorize risk for coronary artery disease without calcium scoring, and that calcium scoring is just one tool for assessing disease risk. Any patient with risk factors for heart artery disease such as high blood pressure, high cholesterol, or a strong family history of heart disease are good candidates for coronary calcium scoring. If you have symptoms that may be due to heart disease such as chest pain or shortness of breath, or if you already have coronary artery stents, heart bypass surgery, or known coronary artery blockages, coronary calcium scoring may not be the best test for you. Talk with your physician to see if calcium scoring may be right for you. At the University of Chicago, our cardiac imaging experts offer coronary calcium scoring for $388.
Scheduling and Contact Information
Cardiac CT angiography requires a physician referral, but you can request a coronary calcium scan without a referral. Talk with your doctor about which test is right for you, or call 1-888-UCH-0200 to schedule an appointment with one of our cardiologists or request an appointment online.
Referring Physicians: To schedule a patient for a cardiac CT angiography study, please call (773) 702-6161.