What is coronary calcium scoring? Cardiology Basics

What is coronary calcium scoring? Cardiology Basics

Coronary calcium scoring is done from a plain multidetector computed tomography (CT) scan. MDCT produces images of coronary arteries in multiple thin slices. Calcium deposits in plaques within the coronary arteries can be found from these images. Calcium deposits occur within atherosclerotic lesions inside the coronary arteries. Some of these plaques can rupture later and lead to clot formation and total occlusion causing acute myocardial infarction.

Coronary calcium scoring can be done as an outpatient test from the X-ray department. As no contrast medium is injected, there is no risk of allergic reactions unlike CT coronary angiography. For the same reason, there is also no risk of contrast induced acute kidney injury. A few seconds of breath holding during the scan procedure give better images. ECG leads connected to the chest can be used to gate the scan images for getting timed images in diastole.

The total amount of calcium in the major coronary branches is calculated and given as an Agatston score. A zero score would mean that there is no calcium deposits in the coronary arteries and low risk of myocardial infarction in the near future. Higher the score, higher the risk.

A score of 100 – 300 indicates moderate amount of calcium in the plaques and carries somewhat high risk of myocardial infarction, while a score more than 300 carries a very high risk. All these values are not absolute, because it is only a single factor. Other risk factors in the individual have to be assessed by an expert physician to quantify the risk more accurately and take appropriate preventive measures.

For that matter, a zero coronary artery calcium score does not mean a zero risk for myocardial infarction. About one fourth to one third of incident cardiovascular disease events occur in those with a coronary calcium score of zero! This is particularly relevant in younger individuals who tend to have lesser calcium in the walls of coronary arteries. Atherosclerotic plaques without calcium can also rupture and cause thrombus formation over it and cause a myocardial infarction sometimes. This emphasizes the need for a preventive strategy of healthy lifestyle right from early life [1].

Reference

1. Hussain A, Ballantyne CM, Nambi V. Zero Coronary Artery Calcium Score: Desirable, but Enough? Circulation. 2020 Sep 8;142(10):917-919. doi: 10.1161/CIRCULATIONAHA.119.045026. Epub 2020 Sep 8. PMID: 32897743.