A coronary artery calcium scoring
, or coronary calcium score test
, is a CT scan of the heart
. It measures the amount of “calcium” in the arteries (the vessels that carry blood away from the heart) to evaluate the risk of a heart attack or stroke.
The calcium mentioned here is not calcium on the teeth. Instead, it’s the special kind of calcium that is tied with plaque (calcified plaque)
Since calcified plaque affects blood flow, the amount of calcium is a sign of the condition of the heart.
In general, the more
the calcium there is, the higher
the risk of a heart attack or stroke in the next 5-10 years.
||Presence of CAD
||No evidence of CAD
||Minimal evidence of CAD
||Mild evidence of CAD
||Moderate evidence of CAD
||Extensive evidence of CAD
When the score goes above 400, it means a severe risk of heart attack in 5-10 years.
A CAC score 400 doesn't directly mean 40% of the artery is blocked. The score is based on the weighted density score given to the highest attenuation value (HU) multiplied by the area of the calcification speck.
if a calcified speck has a maximum attenuation value of 400 HU, the weighted density score is given as 4, and it occupies 8 sq mm area, then its calcium score will be 32.
The score of every calcified speck is summed up to give the total calcium score.
Although a high CAC score points to a higher risk of CAD, a zero value doesn't mean 100 percent safe. Because in some plaque deposition, there's no calcification, which means the blockage isn't captured by the CAT. This isn't common, but cases exist.
Risk factors for extensive calcification of coronary artery include:
- old age
- high cholesterol
- high blood pressure
- chronic kidney disease
- parathyroid dysfunction
Keywords: coronary artery calcium scoring; coronary calcium score.