Diagnosing Heart Disease With Cardiac Computed Tomography (CT)
Coronary CT Angiography (CTA) continued...
Since it's noninvasive, a coronary CTA can be performed much faster than a cardiac catheterization (also called a "cardiac cath" or coronary angiogram), with potentially less risk and discomfort to the patient, as well as less recovery time.
Although coronary CTA exams are growing in use, coronary angiograms remain the "gold standard" for detecting coronary artery stenosis, which is a significant narrowing of an artery that could require catheter-based intervention (such as stenting) or surgery (such as bypassing) to treat the narrowed area. However, coronary CTA has consistently shown the ability to rule out significant narrowing of the major coronary arteries. This new technology also can noninvasively detect "soft plaque," or fatty matter, in the coronary artery walls that has not yet hardened but that may lead to future problems without lifestyle changes or medical treatment.
Coronary CTA is most useful to determine whether symptoms of chest pain may be caused by a coronary blockage, particularly in individuals that may be at risk, such as those with a family history of cardiac events, diabetes, high blood pressure, smokers, and/or those with elevated cholesterol. However, there is still much controversy as to when a coronary CTA should be used.
Total Body CT Scan (TBCT)
The total body CT scan, or TBCT, is a diagnostic technique that uses computed tomography to help identify potential problems or diseases before symptoms even appear.
The TBCT scan -- which takes about 15 minutes to perform -- analyzes three major areas of the body: the lungs, the heart, and the abdomen/pelvis.
In the heart, the scan can detect aortic aneurysms and calcium deposits within plaque in the coronary arteries. However, the presence of calcium deposits in the coronary arteries does not necessarily mean that an artery is dangerously narrowed by disease or that a severe health threat exists. For example, calcium deposits are often found in older people as a result of their age. In addition, the CT scan cannot give a precise location of the diseased portion of the artery.
For some high-risk individuals, the proposed benefit of having a TBCT scan lies in the potential of early detection and treatment. But overall, its use for early detection of heart disease is very controversial.
In the Pipeline: PET/CT Heart Scans
Positron emission tomography (PET) scanning combined with CTA is on the horizon for the detection of heart disease.
PET scans are a form of nuclear medicine -- "nuclear" being the small dose of radioactive material you are injected with before the test (the radiation exposure is similar to that of a standard X-ray). As with CTA, PET involves a doughnut-like scanning device that takes the images.
With PET, the cardiologist and radiologist can examine biological functions, like blood flow or glucose metabolism of the heart. CTA shows the heart's shape and volume.
There is a debate among cardiologists over the appropriateness of PET/CTA for heart diagnosis; more research is needed.