Impact of 2016 SCCT/STR guidelines for coronary artery calcium scoring of noncardiac chest CT scans on lung cancer screening CT reporting

The 2016 SCCT/STR guideline for coronary artery calcification (CAC) scoring on non-cardiac chest CT (NCCT) scans explicitly calls for the reporting of CAC. Whether the publication of the 2016 SCCT/STR guideline has had any impact on CAC reporting in lung cancer screening (LCS) scans has not been investigated. Consecutive patients with a LCS scan were identified from the University of Minnesota LCS registry and evaluated for CAC reporting in 3 separate cohorts: 6 months before, 6 months after, and 1 year after the publication of the 2016 SCCT/STR guideline. Scans were evaluated for CAC and quantified using the Agatston method. CAC reporting, downstream testing and initiation of preventive therapy were assessed. Among 614 patients (50% male, mean age 64.1 +/- 6.0 years), CAC was present in 460 (74.9%) with a median Agatston score of 62 (IQR 0, 230). Of these, 196 (31.9%) had a CAC score of 1-100, 125 (20.4%) had 101-300, and 118 (19.2%) had > 300. Overall, CAC was reported in 325 (70.7%) patients with CAC present. CAC reporting relative to publication of the 2016 SCCT/STR guideline was as follows: 6 months prior-74.1%, 6 months after-64.6%, and 1 year after-77.5%. In the 308 patients with a new diagnosis of sub-clinical CAD based on CAC presence, 6 (1.9%) patients were referred to cardiology, and 15 (4.9%) patients underwent testing for obstructive CAD. Only 6 (1.9%) and 9 (2.9%) patients were newly started on aspirin and statin respectively. CAC detected incidentally on lung cancer screening CT scans is prevalent, and rarely acted upon clinically. CAC reporting is fairly high, and publication of the 2016 SCCT/STR guideline for CAC scoring on NCCT scans did not have any significant impact on CAC reporting.

Automated summary

The 2016 SCCT/STR guideline for coronary artery calcification scoring did not significantly impact reporting of CAC on lung cancer screening CT scans. Despite a high rate of CAC reporting, incidental detection of CAC on these scans is common and often does not lead to clinical intervention.