Detection of coronary calcium during standard chest computed tomography correlates with multi-detector computed tomography coronary artery calcium score

The correlation between formal coronary artery calcium scoring (CACS) determined by multi-detector CT (MDCT) and the presence of coronary calcium on standard non-gated CT chest examinations was evaluated. In 163 consecutive healthy participants, we performed screening same-day standard non-gated, non-enhanced CT chest exams followed by high-resolution, ECG-synchronized MDCT exams for CACS. For the standard CT examinations, a scoring system (Weston score, range 0–12) was developed assigning a score (0–3) for each coronary vessel including the left main trunk. Overall, 30% and 39% of patients had CAC on standard CT and MDCT exams, respectively (P = 0.13). CAC on standard CT was highly correlated to the Agatston CACS on the MDCT (Spearman correlation coefficient 0.83, P < 0.001). Absence of calcium on the standard CT exam was associated with a very low CACS (mean Agatston 0.5, range 0–19). A Weston score >2 identified a CACS > 100 with an area under the curve of 0.976, sensitivity of 100%, and specificity of 85%. A Weston score >7 identified a CACS > 400 with an area under the curve of 0.991, sensitivity of 100%, specificity of 98%. The intra-observer variability was low as was the inter-observer variability between a cardiac specialized radiologist and a non-specialized reader. A visual coronary artery scoring system on standard, non-gated CT correlates well with traditional methods for CACS. Further, a non-expert cardiac radiologist performed equally well to a cardiac expert. This information suggests that a visual scoring system, at least in a descriptive manner can be utilized for a general statement about coronary artery calcification seen on standard CT imaging to guide clinicians in risk stratification.