Turning routine chest CT into a cardiovascular risk test: weston score-based CAC in Hawai'i

Coronary artery calcium (CAC) is a robust predictor of cardiovascular risk and is recommended by contemporary prevention guidelines. However, dedicated Agatston scoring is underutilized because of cost and limited availability. Visual assessment using the Weston Score (WS) on routine non-contrast chest CT (NCCT) offers a practical alternative, although data in Asian populations remain limited.

We retrospectively reviewed 1107 consecutive NCCT studies performed in 2024. After exclusions, 842 patients were included. WS was visually assessed and converted to Agatston-equivalent CAC scores using a validated method. MESA reference data were used to estimate age-, sex-, and race-adjusted CAC percentiles. Interobserver agreement among a resident physician, cardiologist, and medical student was evaluated using intraclass correlation coefficients (ICC) and Bland-Altman analyses.

Mean age was 70.8 ± 10.2 years, 51% were female, and 88.5% were Asian. Agatston-equivalent CAC scores were 0 in 17.0%, 1-99 in 20.9%, 100-399 in 34.0%, 400-999 in 17.7%, and > 1000 in 10.5%. Among patients with percentile estimates (n = 830), 52.2% were in the 76th-100th percentile. Interobserver agreement was excellent for WS (ICC 0.88), Agatston-equivalent scores (ICC 0.84), and CAC percentiles (ICC 0.90), with minimal systematic bias.

Visual WS assessment on routine NCCT provides reproducible estimation of CAC burden and MESA percentiles, supporting opportunistic CAC reporting to improve cardiovascular risk stratification in multiethnic populations.