Application of the Novel Two-Compartmental Model to Quantify Coronary Artery Calcium: A Pilot Study

<b>Background</b>: Cardiovascular disease (CVD) remains a major global health concern and the leading cause of mortality and disability. Early detection and prevention strategies rely heavily on evaluating coronary artery calcification, traditionally assessed using the coronary artery calcium score (CACS). However, CACS is limited by its dependence on strictly fixed tube voltage and slice thickness, sensitivity to changes in scanning parameters, and the need for an additional dedicated coronary calcium scan that increases radiation exposure. <b>Methods</b>: To address these challenges, we developed a novel two-compartment coronary artery calcium score system (TACS) for quantitative calcium assessment. TACS was established and validated using a QRM Thorax phantom scanned on a GE Revolution CT at 70-140 kVp. Volumetric calcium density (VCD) derived from TACS was compared with conventional CACS under varying slice thickness, pitch, and iterative reconstruction algorithms. Additionally, coronary artery calcium scans from 15 patients were retrospectively analyzed to assess correlations between TACS and CACS. <b>Results</b>: TACS demonstrated stable performance across tube voltages, with VCD errors ranging from 3.8% to -19.0% and maintained consistency under different slice thicknesses (23.9% to -2.3%) and reconstruction algorithms, showing near-zero residual percentages. Patient analyses revealed a strong correlation between TACS and CACS (r = 0.932). <b>Conclusions</b>: These findings suggest that TACS provides robust and reliable quantification of coronary calcium, supporting its potential use for opportunistic coronary artery disease screening, particularly in routine CT imaging. Further studies with larger cohorts are warranted to confirm its clinical applicability.