Optimization of 3D time-of-flight MR angiography with shortened echo time and dual-echo acquisition

摘要

A dual-echo three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) pulse sequence is developed. To improve the visualization of artery, optimal echo time (TE) is achieved using minimal gradient durations, asymmetric radio-frequency (RF) excitation pulses, and partial echo acquisition. The effect of shortened TE on artery-to-background contrast is demonstrated. Vessel visualization is substantially improved in TOF with short TE of 5.7ms comparing to that with a long TE of 18.3ms. Using a dual-echo acquisition approach, the scan time can be reduced by 50%, with a slight penalty in vessel visibility. When the same scan time is used, the dual-echo acquisition is demonstrated to improve the signal-to-noise-ratio (SNR) or the spatial resolution of MRA.