Since the turn of the 19th century, cardiovascular disease has become the number one killer in the United States. Many modalities are available for the assessment of coronary artery disease (CAD). These include treadmill exercise stress test, stress echocardiography and nuclear myocardial perfusion study. Adenosine stress cardiac magnetic resonance imaging is also a recent modality for the assessment of CAD. The introduction of Multi-slice Computed Tomography (MSCT) now allows non-invasive imaging of the coronary and peripheral arteries.
Similar to a CT scan of the body, iodinated contrast is injected through a vein in the arm. However, because of the rapid rate of the heart, examination of the heart and coronary arteries is challenging. With the introduction of state of the art 64 slice CT scanner, we are now able to “freeze” the motion of the heart to image the coronary arteries with a high resolution. Coronary CT angiography has become quite useful in ruling out significant coronary artery disease in individuals with a low to moderate cardiac risk. Coronary CT angiography allows a less invasive, quicker and safer alternative to the traditional angiography.
Another application for CT is to evaluate coronary calcification. The CT scan in conjunction with computer software generates a coronary calcium score that can predict a cardiovascular even such as a heart attack. Such information can assist physicians in risk stratifying patients and the use of appropriate medications in order to reduce the risk of vascular event in the future.
Cardiovascular Magnetic Resonance Imaging (CMR) has emerged as the “gold standard” to assess heart function. CMR is able to look at the heart from any view without being constrained by the patient’s habitus. The images are very reproducible, enabling physicians to reliably compared patient’s findings over time when repeated studies are performed. Another recent advance is the “viability” or “scar” imaging that allows CMR to precisely detect any heart damage as a result of heart attack. The scan is performed following administration of “Gadolinium”, the commonly used, standard contrast agent for MRI that has little, if any in the way of side-effects, and is extremely well-tolerated by patients. The results of viability CMR studies are important in determining whether or not a patient has had a heart attack, and how much heart muscle has been damaged. The results are particularly valuable for Cardiologists when considering performing a coronary artery angioplasty or for Cardiac Surgeons planning coronary artery bypass surgery.
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Cardiac CT for Calcium Scoring
Coronary Computed Tomography Angiography (CTA)