Dual-source CT coronary angiography: Image quality, mean heart rate, and heart rate variability

OBJECTIVE. The purpose of this study was to evaluate the effect of mean heart rate and heart rate variability on the image quality of dual-source CT coronary angiography. SUBJECTS AND METHODS. Eighty patients underwent dual-source CT coronary angiography. Thirteen data sets were reconstructed in 5% steps from 20-80% of the R-R interval. Heart rate variability was calculated as SD of mean heart rate. Two independent blinded reviewers assessed the image quality of each segment. RESULTS. Mean heart rate was 65.3 +/- 13.9 (SD) beats per minute (bpm) (range, 35-99 bpm) with a variability of 3.4 +/- 4.1 bpm (range, 0.4-17.5 bpm). Image quality was sufficient for diagnosis for 97.8% (1,043/1,066) of arterial segments. No significant correlation was found between mean heart rate and image quality in any segment or any coronary artery. No significant correlation was found between heart rate variability and image quality in any segment, the right coronary artery, or the left anterior descending artery, but there was a significant (p < 0.05) correlation in the left circumflex artery. A significant correlation (p < 0.05) between overall image quality was found for mean and variability of heart rate as shared predictors, the latter having a greater contribution. CONCLUSION. The overall image quality of dual-source CT coronary angiography is sufficient for diagnosis within a wide range of mean heart rates and variability of heart rates. Only heart rates that are both high and variable significantly deteriorate image quality, but the quality remains adequate for diagnosis.