UCLA

PURPOSE: To perform a retrospective review of Coronary Artery Disease Reporting and Data System (CAD-RADS) adoption at a high-volume cardiac CT service. MATERIALS AND METHODS: In this retrospective study, the adoption of CAD-RADS in 6562 coronary CT angiography (CTA) reports from January 1, 2017, to February 13, 2020, was evaluated. Reports without CAD-RADS were classified as opt-outs or exceptions to CAD-RADS. CAD-RADS classifications were retrospectively assigned to the opt-outs and the clinical indications for coronary CTA. RESULTS: CAD-RADS scores were reported in 95% (6264 of 6562) of cases. Among the 5% (n = 298) of reports not reported according to CAD-RADS, 58% (n = 172) were considered opt-outs and 42% (n = 126) were exceptions. Cases with higher degree of stenosis, stents, and coronary artery bypass grafts (CABGs) occurred more often in opt-outs versus reports with CAD-RADS (odds ratio [OR], 8.3 [95% CI: 1.6, 42.1]; P < .001). The quarterly opt-out rate decreased over consecutive quarters in the 1st year (OR, 0.77 [95% CI: 0.61, 0.96]; P = .01), then stabilized. Quarterly opt-out rate for patients with stents decreased over time (OR, 0.82 [95% CI: 0.73, 0.92]; P = .008), as did the opt-out rates in patients with CABG (OR, 0.83 [95% CI: 0.76, 0.91]; P < .001). Exceptions (n = 126) included coronary dissections (44%), anomalous coronary arteries (41%), coronary artery aneurysms or pseudoaneurysms (10%), vasculitis (2%), stent complications (2%), and extrinsic compression of grafts (2%). CONCLUSION: CAD-RADS was adopted rapidly and widely. Readers opted out of its use most often in complex cases of CAD, and the most common exceptions were coronary dissections and anomalous coronary artery.Keywords: Coronary Arteries, CT Angiography© RSNA, 2021.