Diagnosing Heart Disease With Cardiac Computed Tomography (CT)
Coronary CT Angiography (CTA) continued...
Before the test, an iodine-containing contrast dye is injected into an IV in the patient's arm to improve the quality of the images. A medication that slows or stabilizes the patient's heart rate may also be given through the IV to improve the imaging results.
During the test, which usually takes about 10 minutes, X-rays pass through the body and are picked up by special detectors in the scanner. The newer scanners produce clearer final images with less exposure to radiation than the older models. These new technologies are often referred to as "multidetector" or "multislice" CT scanning.
Another new technology, known as dual-source CT, uses two sources and two detectors at the same time. This technology provides full cardiac detail with about 50% less radiation exposure than traditional CT.
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.