Optimal heart rate threshold for phase selection in beta-blocker-free coronary CT angiography using second-generation...

Area of Science:

• Cardiovascular Imaging
• Radiology
• Medical Technology

Background:

• Beta-blocker-free coronary CT angiography (CCTA) offers workflow advantages but is limited by motion artifacts at higher heart rates.
• Advancements like faster gantry rotation and second-generation spectral-shaping filter (SSF2) may mitigate these limitations.

Purpose of the Study:

• To determine the optimal heart rate (HR) cutoff for phase selection in beta-blocker-free CCTA using SSF2.
• To evaluate the impact of SSF2 on image quality and diagnostic performance.

Main Methods:

• Retrospective analysis of 368 patients undergoing beta-blocker-free CCTA with a 256-row CT scanner.
• Images reconstructed with and without SSF2, with image quality graded on a 5-point Likert scale.
• Receiver operating characteristic (ROC) curve analysis to identify the optimal HR cutoff for phase selection.

Main Results:

• SSF2 significantly improved image quality and evaluability across all segments (P < 0.001).
• The optimal HR cutoff for phase selection was 67 bpm, achieving 91.8% evaluability.
• At HR ≤ 67 bpm, diastolic SSF2+ images were superior; at HR > 67 bpm, systolic SSF2+ images were optimal.
• Diagnostic performance for ≥50% stenosis showed 91.3% sensitivity, 88.3% specificity, and 89.0% accuracy.

Conclusions:

• SSF2 facilitates reliable beta-blocker-free CCTA, overcoming HR limitations.
• An HR cutoff of 67 bpm effectively guides phase selection, ensuring high scan evaluability and diagnostic accuracy.