Single-shot GRASE imaging with short effective TEs.
A new phase-encoding scheme for gradient- and spin-echo (GRASE) imaging giving a short effective TE is described. Unlike previous orders, phase encoding is centric rather than sequential. The sequence is a development of k-banded GRASE that uses different time segments of the echo train to encode different bands of k space. This phase-encoding order has been implemented in single-shot sequences on an imager with high performance gradients. Approximately 144 phase-encoding lines can be acquired in an echo train time of 390 ms. With centric phase encoding, the effective TE is 8 ms, compared with 75 ms for sequential encoding, and signal-to-noise ratios (SNRs) in brain tissue are 50 to 70% higher. The sequence can be employed in, for example, diffusion and velocity imaging.
Johnson
G
G
Department of Radiology, New York University Medical Center, NY 10016, USA.
Feinberg
D A
DA
Venkataraman
V
V
D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology; D003198:Computer Simulation; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D013997:Time Factors