Minimizing radiation dose in coronary CT angiography using dual single-cardiac phase acquisition with a whole-heart motion correction technology: a prospective randomized study on image quality

Coronary computed tomography angiography (CCTA) plays an increasingly important role in coronary artery disease (CAD) evaluation, but radiation dose remains a clinical concern. Conventional multi-cardiac phase (CMP) scanning covers wide R-R intervals to ensure optimal image quality, leading to higher radiation exposure. Recent advances in motion correction technology, particularly whole-heart motion correction algorithms, offer potential solutions for dose reduction. This study aimed to evaluate the feasibility of using dual single-cardiac phase (DSP) acquisition (end-systole: 45% R-R interval and end-diastole: 75% R-R interval) in CCTA with a whole-heart motion correction (SnapShot Freeze 2, SSF2) technology to minimize radiation dose and maintain image quality in comparison with CMP scanning. In this prospective randomized study, 140 patients were randomly assigned to either DSP (n=70) or CMP (n=70) scanning groups. All examinations were performed on a 256-row wide-detector computed tomography (CT) scanner with similar data acquisition parameters and reconstruction algorithms except cardiac phase range selections. Image quality was assessed both objectively [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)] and subjectively (5-point scale). Image quality, diagnostic confidence, and acceptability between the two groups and across different heart rates were evaluated. DSP scanning achieved 29% radiation dose reduction [volume CT dose index (CTDIvol): 19.24±4.59 vs. 27.01±6.02 mGy, P<0.001] with comparable image quality scores in both systolic {5, [interquartile range (IQR), 5.0-5.0] vs. 5 (IQR, 5.0-5.0), Reader 1: P=0.591, Reader 2: P=0.587} and diastolic phases [5 (IQR, 4.0-5.0) vs. 5 (IQR, 4.0-5.0), Reader 1: P=0.908, Reader 2: P=0.951]. All scans in our study cohort were diagnostically acceptable (100%) when both phases were available. Using only systolic or diastolic phases reduced acceptability to 97.1% and 94.3%, respectively. DSP scanning with SSF2 technology achieves significant radiation dose reduction while maintaining comparable image quality to CMP, with 100% diagnostic acceptability when both phases are available.