Comparison of free-breathing 3D coronary MR angiography using the volume-targeted and whole-heart methods

Objective:To make a comparison between the RCA-and LCX-targeted and whole-heart 3D coronary MR angiography using a T2-prepared SSFP sequence with real-time navigation.Materials and Methods:Twenty-one volunteers underwent free-breathing navigator-gated 3D coronary MR angiography,including both RCA-and LCX-targeted MR angiography and whole-heart coronary MR angiography with comparable imaging parameters on a 1.5 T whole-body MR system.We compared the acquisition time,the overall image quality of each segments of RCA and LCX,measured the length of the RCA and LCX,and assessed the posterior descending arterial branches of the RCA obtained with the volume-targeted and whole-heart approaches.Statistical analysis was performed with P value less than 0.05 considered signifi cant.Results:The imaging time required for whole-heart acquisition was signifi cantly longer than the RCA-and LCX-targeted acquisition (whole-heart,9.82±2.62 vs volume-targeted,4.31±0.87 minutes;P0.05).The depicted length of the coronary arteries were not significantly different between the whole-heart and volume-targeted coronary MR angiography (whole-heart,RCA/LCX=12.2±3.4/7.81±1.5 vs volume-targeted,RCA/LCX= 11.9±3.2/7.59±1.2 cm;P0.05).Whole-heart method had advantages for the visualization of posterior descending artery branches derived from the RCA.However,volume-targeted method yields higher vessel sharpness and overall image quality in comparison with whole-heart acquisition (volume-targeted,RCA/LCX = 4.33±0.97/4.29±0.89 vs whole-heart,RCA/LCX= 3.84±1.03/3.59±0.86;P0.05).Conclusion:Volume-targeted and whole-heart navigator-assisted coronary MR angiography had its own advantages respectively,and the combined use of the two methods could be potentially helpful for clinical applications.