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.

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.