Head-to-head comparison of prospectively triggered vs retrospectively gated coronary computed tomography angiography: Meta-analysis of diagnostic accuracy, image quality, and radiation dose

Background In coronary computed tomography (CT) angiography (CTA) prospective electrocardiography triggering requires less radiation dose than retrospective electrocardiography gating but provides less cardiac phases for interpretation. This meta-analysis presents a concise and comprehensive head-to-head comparison of image quality, diagnostic accuracy, and radiation dose of prospectively triggered coronary CTA vs retrospectively gated CTA in patients with suspected or known coronary artery disease (CAD). Methods In patients with CAD and without tachyarrhythmia, eligible studies (selected from 4 databases) compared prospectively triggered vs retrospectively gated CTA (performed with ≥64-slice CT or dual-source CT) in 2 groups having approximately similar patient characteristics, scored CTA image quality, and/or assessed how accurately CTA diagnoses ≥50% coronary stenoses compared with catheter angiography and reported the radiation dose. The data were meta-analyzed by random-effects models, with CIs provided in the text. Results Among 3,330 patients from 20 included studies, 91.3% of CTAs (segments: 97.8%) had diagnostic quality with prospective triggering and 93.3% of CTAs (segments: 98.4%) with retrospective gating ( P > .05). Among 664 patients from 5 studies, the pooled sensitivity/specificity of diagnostic CTAs was 98.7%/91.3% (segment level: 91.3%/97.7%) with prospective triggering and 96.9%/95.8% (segment level: 93.1%/97.6%) with retrospective gating ( P > .05). The pooled effective dose was 3.5 mSv with prospective triggering and thus, by a factor of 3.5, lower than the pooled effective dose of retrospective gating, which was 12.3 mSv ( P < .01). Conclusions In patients with CAD and without tachyarrhythmia, prospectively triggered coronary CTA provides image quality and diagnostic accuracy comparable with retrospectively gated CTA, but at a much lower radiation dose.