High-Pitch Coronary Computed Tomographic Angiography Using the Third-Generation Dual-Source Computed Tomography: Initial Experience in Patients With High Heart Rate

OBJECTIVE: This study aimed to evaluate the feasibility, image quality, and radiation dose of prospectively high-pitch coronary computed tomographic (CT) angiography in patients with high heart rates (HRs) using the third-generation dual-source CT. METHODS: One hundred consecutive patients with sinus rhythm and HR between 70 and 100 beats per minute were enrolled into this study. All patients were divided into 2 groups. Patients in group A (n = 46) were examined with prospectively high-pitch scan mode in which image acquisition was triggered at 30% of the R-R interval. Patients in group B (n = 54) were scanned with prospectively sequential mode, and the acquisition window was set at 30% to 50% of the R-R interval. Objective and subjective evaluations were performed. Diagnostic ratios and radiation dose were compared between the 2 groups. RESULTS: No statistical differences were found in objective parameters and subjective assessment of image quality between the 2 groups. Diagnostic ratios were as follows: 89.1% vs 94.4% (patient based), 95.1% vs 97.7% (vessel based), and 97.8% vs 98.8% (segment based) for group A and group B, respectively (all P > 0.05). Radiation dose was significantly lower in group A (0.53 ± 0.14 mSv) as compared with group B (1.33 ± 0.17 mSv; P < 0.01). CONCLUSIONS: For patients with high HR and without cardiac arrhythmia, the prospectively high-pitch spiral acquisition using third-generation dual-source CT at systolic phase can provide images with comparatively high diagnostic ratio and significantly lower radiation dose as compared with prospectively sequential acquisition mode.