Johnson G, Feinberg D A, Venkataraman V
Department of Radiology, New York University Medical Center, NY 10016, USA.
J Magn Reson Imaging. 1996 Nov-Dec;6(6):944-7. doi: 10.1002/jmri.1880060617.
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.
描述了一种用于梯度和自旋回波（GRASE）成像的新型相位编码方案，该方案可提供短有效回波时间（TE）。与以前的顺序不同，相位编码是中心式的而非顺序式的。该序列是k带GRASE的发展，它使用回波串的不同时间段来编码k空间的不同频段。这种相位编码顺序已在具有高性能梯度的成像仪上的单次激发序列中实现。在390 ms的回波串时间内可采集大约144条相位编码线。采用中心式相位编码时，有效TE为8 ms，而顺序编码时为75 ms，脑组织中的信噪比（SNR）高50%至70%。该序列可用于例如扩散成像和速度成像。
