动脉自旋标记的同时多层回波平面成像。
Arterial spin labeling with simultaneous multi-slice echo planar imaging.
机构信息
Helen Wills Institute of Neuroscience, University of California, Berkeley, Advanced MRI Technologies, Sebastopol, California, USA.
出版信息
Magn Reson Med. 2013 Dec;70(6):1500-6. doi: 10.1002/mrm.24994. Epub 2013 Oct 15.
PURPOSE
Simultaneous multi-slice (SMS) echo planar imaging (EPI) is incorporated into two-dimensional (2D) arterial spin labeling (ASL) imaging to produce more slices for measuring perfusion in a larger region of the brain than currently possible with multi-slice EPI.
METHODS
Pulsed ASL (PASL) preparations using FAIR and QUIPSS II techniques were combined with SMS-EPI. Testing was performed in four subjects at 3 Tesla. Multiband slice acceleration factors (MB) from MB-2 to MB-5 using 40 averages were evaluated. Comparisons were made quantitatively to PASL 2D EPI and qualitatively to PASL 3D GRASE.
RESULTS
In the 12 slice data set, spatial SNR for the perfusion weighted images averaged across subjects was 3.28 and 3.44 for the two sequential MB-1 acquisitions as control comparison, 3.25 for MB-2 and 2.98 for MB-3. The temporal SNR averaged 1.01 and 0.99 for MB-1, 0.89 for MB-2, and 0.78 for MB-3. For whole-brain spatial coverage, the 20 slice data sets could be acquired in narrower time windows, from 874 ms using EPI (MB-1) down to 196 ms using MB-5. SMS-EPI ASL differed from 3D GRASE ASL, which can use background suppression and has less susceptibility artifact as a CPMG SE sequence.
CONCLUSION
SMS-EPI has a major advantage over EPI-based ASL imaging by increasing slice coverage without lengthening the acquisition time window.
目的
在二维（2D）动脉自旋标记（ASL）成像中加入同时多层（SMS）回波平面成像（EPI），以便在比目前多切片 EPI 更大的脑区测量灌注，生成更多的切片。
方法
使用 FAIR 和 QUIPSS II 技术的脉冲 ASL（PASL）准备与 SMS-EPI 相结合。在 3T 下对 4 名受试者进行了测试。使用 40 个平均切片评估了多带片加速因子（MB）从 MB-2 到 MB-5 的效果。与 PASL 2D EPI 进行了定量比较，并与 PASL 3D GRASE 进行了定性比较。
结果
在 12 切片数据集，两个连续 MB-1 采集的灌注加权图像的空间 SNR 为 3.28 和 3.44，作为对照比较，MB-2 的空间 SNR 为 3.25，MB-3 的空间 SNR 为 2.98。时间 SNR 平均为 MB-1 的 1.01 和 0.99，MB-2 的 0.89，MB-3 的 0.78。对于全脑空间覆盖，20 切片数据集可以在更窄的时间窗口中采集，从使用 EPI（MB-1）的 874ms 下降到使用 MB-5 的 196ms。SMS-EPI ASL 与 3D GRASE ASL 不同，3D GRASE ASL 可以使用背景抑制，并且作为 CPMG SE 序列，具有更少的磁化率伪影。
结论
SMS-EPI 通过在不延长采集时间窗口的情况下增加切片覆盖范围，在基于 EPI 的 ASL 成像方面具有很大的优势。
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