Optimization of fast cardiac imaging using an echo-train readout

Fast gradient-echo sequences that use an echo-train readout are becoming more widely used, particularly for imaging the heart. An important issue for these sequences involves determining the optimal duration for the echo-train readout. In normal volunteer scans and theoretically the echo-train readout duration was varied from 2.4 to 32.8 msec. Myocardial signal-to-noise ratio (SNR), myocardium-tag signal difference-to-noise ratio (SDNR), flow artifact-to-noise ratio (FNR), and geometric distortion were measured and/or calculated. Our results showed that to obtain high SNR, SDNR, and data acquisition efficiency while minimizing FNR and geometric distortion, the readout duration should be 10-15 msec at 1.5 T.