CAC evaluation

In this study, we adopted a simple visual CAC scoring method throughout the entire coronary circulation in noncontrast noncardiac chest CT scans recommended by 2016 SCCT/STR guidelines [12]. In the CAC scoring adopted, the calcification degree was recorded according to the severity of calcification: 0: no calcification; 1: only isolated spot of CAC within a segment; 2: the degree of calcification is between 1 and 3 points; 3: continuous CAC within a segment [12]. Some representative images are shown in Fig. 1. We merged points 0 and 1 into low CAC group, while points 2 and 3 were combined into high CAC group. CAC was evaluated independently by two cardiothoracic radiologists (J.Z. and S.L. both with 12 years of experiences in cardiovascular radiology) in core lab of Jinling Hospital, Medical School of Nanjing University. Any disagreement was resolved by consensus reading.

Representative CAC evaluation of patients with COVID-19, A Point 0: no coronary calcification is observed on chest CT image; B Point 1: only isolated spot of CAC is seen within a segment; C Point 2: the degree of calcification is between points 1 and 3; D Point 3: continuous CAC is observed within a segment. Points 0 and 1 are classified as low CAC groups, while points 2 and 3 are classified as high CAC groups