Aortic Arch Calcification in Ungated Lung Computed Tomography Scans as Predictors of Atherosclerotic Cardiovascular Disease: Methodology and Reproducibility in a Multi-Ethnic Study of Atherosclerosis.

Background: Aortic arch calcium (AAC), which is frequently detected on ungated lung computed tomography (CT) due to a large field of view, can serve as a marker of subclinical atherosclerotic burden. Our study sought to validate novel cardiac screening metrics of subclinical atherosclerosis by evaluating the inter- and intra-observer reproducibility of AAC measurements with ungated lung CT.

Methods: The authors randomly selected 100 ungated lung CT scans from the Multi-Ethnic Study of Atherosclerosis cohort. A Bland-Altman plot analysis was used to test inter- and intra-reader reproducibility, after measuring the total arch calcium score and arch calcium volume.

Results: The intra-reader reproducibility for the total arch calcium score and arch calcium volume in all subjects was excellent at 99% and 97%, respectively. The inter-reader reproducibility for the total arch calcium score and volume in all subjects was similarly excellent at 97% and 96%, respectively.

Conclusions: The high reproducibility of ungated lung CT suggests a potential new method of stratifying the atherosclerotic cardiovascular disease risk among patients undergoing lung CT without requiring additional scanning. This methodology helps promote routine reporting of AAC and coronary artery calcium based on millions of ungated CT images acquired for lung screening purposes.