Coronary artery motion and cardiac phases: Dependency on heart rate - Implications for CT image reconstruction

This study had institutional review board approval; written informed consent was obtained. The purpose was to prospectively determine the heart rate ( HR) dependency of three- dimensional ( 3D) coronary artery motion by incorporating into analysis the durations of systole and diastole. Thirty patients ( seven women, 23 men; mean age, 56.6 years +/- 12.7 [ standard deviation]; HR: 45 - 100 beats per minute) underwent electrocardiographically gated 64- section computed tomographic ( CT) coronary angiography to determine coronary motion velocities at bifurcation points. Significance of velocity differences ( P<.05) was determined by using analysis of variance for repeated measures and Bonferroni post hoc tests. HR dependency was determined by using linear regression analysis. HR significantly affected 3D coronary motion ( r = 0.47, P <.009) through nonproportional shortening of systole and diastole ( r = - 0.82, P <.001), leading to percentage reconstruction interval shifts of coronary velocity troughs and peaks ( P <.01). Results suggest that image reconstruction algorithms at CT coronary angiography be adapted to the individual patient's HR.