Significance of incidentally detected coronary artery calcium on NCCT

Non-Contrast Computed Tomography (NCCT) of the thorax taken for other reasons may incidentally detect coronary artery calcification. Conventional method of coronary calcium detection is by gated CT Agatston scores. Yet there is strong correlation between NCCT detected coronary calcium and gated CT Agatston scores as well as cardiovascular outcomes [1]. But there are challenges including standardization of coronary artery calcium detected by NCCT, validating its prospective power and avoiding unnecessary investigations as a result of incidentally detected coronary artery calcium. Presence of coronary calcium is indicated by a lesion above 130 Hounsfield Units with an area >1 mm². Agatston score is calculated by multiplying the calcified plaque area by a weighted density score. CAC score categories are 0, 1 to 99, or ≥100, with each correspondingly increasing risk. Those with CAC >300 have 10-year risk equivalent to a secondary prevention population. Coronary calcium score estimation from NCCT scans taken for other reasons may help patients avoid extra radiation by obviating the need for a dedicated scan for that purpose alone.

References

1. Parsa S, Saleh A, Raygor V, Hoeting N, Rao A, Navar AM, Rohatgi A, Kay F, Abbara S, Khera A, Joshi PH. Measurement and Application of Incidentally Detected Coronary Calcium: JACC Review Topic of the Week. J Am Coll Cardiol. 2024 Apr 23;83(16):1557-1567. doi: 10.1016/j.jacc.2024.01.039. PMID: 38631775.