Analysis of heart rate and its variation affecting image quality and optimized reconstruction window in retrospective ECG-gated coronary angiography using multi-detector row CT

It is clinically important to study the effect of heart rate and its variation on image quality, and selection of optimized window in coronary angiography using multi-detector row CT (MDCT). We performed contrast-enhanced coronary angiography using MDCT in 83 patients. Sixty cases with available information of heart rate were enrolled in this study. We systemically analyzed the effect of heart rate and its variation. Two radiologists rated image quality as follows: 4, excellent; 3, good; 2, fair; 1, bad. Cardiac cycle windows at 70 and 40% were routinely selected for image reconstruction. Both of 40% and 70% reconstructed images were available only to fifty-seven cases. Optimized window was rated as 1 when 40% reconstruction was better quality than 70%, as 2 when 40% reconstruction was the same as 70%, and as 3 when 70% reconstruction was better than 40%.