Noninvasive Coronary Angiography with 64-Section CT: Effect of Average Heart Rate and Heart Rate Variability on Image Quality

Abstract

Purpose: To evaluate prospectively the effect of average heart rate and heart rate variability on image quality at 64-section computed tomographic (CT) coronary angiography. Materials and Methods: The study protocol had local ethics committee approval; written informed consent was obtained. There were 125 patients (45 women, 80 men; mean age, 59.9 years ± 12.9 [standard deviation]; 79 receiving β-blockers) who underwent 64-section CT coronary angiography with retrospective electrocardiographic gating. Data sets were reconstructed in 5% steps from 20% to 80% of R-R interval. Heart rate variability was calculated as 1 standard deviation from mean rate during scanning. Two observers rated image quality of each coronary segment at least 1.5-mm diameter (1 = no motion artifacts, 5 = not evaluative). Repeated analysis of variance measurements were performed to evaluate quantitative parameters. Pearson correlation analysis was performed to compare image quality in each patient with average heart rate and heart r...