Cardiac computed tomography (CT) for Calcium Scoring uses special x-ray equipment to produce pictures of the coronary arteries to determine if there is a build-up of plaque – an indicator for atherosclerosis or coronary artery disease (CAD). The information obtained can help evaluate whether one is at increased risk for a heart attack.
What is Coronary artery disease?
The coronary arteries are the vessels that supply oxygen-containing blood to the heart muscle. Atherosclerosis is the process by which there is abnormal plaque deposition in the walls of these arteries which when present is then called coronary artery disease (CAD). CAD either causes progressive narrowing of the arteries leading to poor heart functioning and angina or more catastrophically could result in acute plaque rupture and a heart attack, often without preceding warning. Because calcium is a marker of CAD, the amount of calcium detected on a cardiac CT scan is a helpful prognostic tool. The findings on cardiac CT are expressed as a coronary calcium score.
What are the risks for CAD?
The major risk factors for CAD are:
- high blood cholesterol levels
- family history of heart attacks
- high blood pressure
- cigarette smoking
- overweight or obese
- physical inactivity
How does Coronary Calcium Scoring help?
The coronary calcium score is used to refine the individual’s risk of CAD after looking at the above clinical and laboratory markers. This is particularly useful for those at intermediate risk of CAD (i.e. 5-20% risk of a coronary event in the next 10 years).
The coronary calcium score will guide the medical practitioner as to how aggressively to treat the risk factors for CAD.
Example of Calcium Score Study
The coronary calcium score will also help rationalise the use of statins (cholesterol lowering drugs) avoiding unnecessary use and side effects.
The table below helps illustrate this utility:
Finally, it has been shown that patients who have CAD and have this shown to them on an objective Coronary Calcium Score study are more compliant of their risk factor modification interventions.
Procedure, preparation and cost:
CT for Coronary Calcium Scoring is simple, quick (about 15 minutes in total) and painless. The radiation dose to the individual is minimal and no contrast is required (no injection). The preparation is uncomplicated and one should avoid elevating ones heart rate prior to the procedure (avoid caffeine or strenuous physical activity just before the examination). The cost of the examination is reasonable and may be reimbursed by some medical aids. One should speak to one’s referring doctor for more detail on this.