Abstract 13215: Accuracy of Visual Qualitative Estimates of CAC Incidentally Found on Chest CT Compared With Formal CAC Scoring

Abstract

Introduction: While coronary artery calcium (CAC) scoring improves CVD risk assessment, it remains underutilized and is often not covered by insurance. Coronary calcium can be detected on chest CT scans performed for other indications and may allow identification of higher-risk people without a dedicated CAC scan. However, qualitative CAC scoring on non-gated chest CT scans is not widely validated. Methods: Since 2016, radiologists at two large health systems in Dallas (an academic medical system and a large safety net hospital) have routinely documented the presence and severity of CAC (none, mild, moderate, large) on all chest CT scans. We identified all adults who underwent both dedicated CAC scanning and a separate chest CT scan within 6 months. We compared qualitative visual CAC by CT scan versus a CAC score from a dedicated, gated coronary CT scan. Results: From 2016-2021, 891 patients (mean age 60 ± 12y, 43% male, 61% White, 35% Black, 24% Hispanic) underwent both a CT scan and a CAC score. Of these, 424 had no CAC, 268 small, 137 moderate, and 62 large CAC on CT scan. Qualitative CAC estimate from non-gated CT scans were highly correlated with formal CAC scores (Kendalls tau-b=0.75, p<0.0001, figure). To detect CAC (score >0), qualitative assessment on CT had a sensitivity of 82%, specificity of 95%, positive predictive value (PPV) of 97%, and negative predictive value (NPV) of 77%. Only 6% with small, 1% with moderate, and 0% with large CAC on CT had a CAC score = 0. For detection of CAC ≥ 100, moderate to large CAC on CT had a sensitivity of 62%, specificity of 96%, PPV of 89%, and NPV of 84%. Discussion: At two different hospitals serving a diverse population, visual estimates of CAC on routine CT scans were strongly correlated with formal CAC scores from dedicated, gated CT scans. Incidental identification of CAC on routine CT scans should prompt more aggressive cardiovascular risk reduction, particularly when moderate to large CAC burden is seen.