Erwin L. Hahn Institute for Magnetic Resonance Imaging, UNESCO-Weltkulturerbe Zollverein, Leitstand Kokerei Zollverein, Arendahls Wiese 199, D-45141 Essen, Germany.
Neuroimage. 2012 Sep;62(3):1939-46. doi: 10.1016/j.neuroimage.2012.05.080. Epub 2012 Jun 6.
This article demonstrates the application of spin-echo EPI for resting state fMRI at 7 T. A short repetition time of 1860 ms was made possible by the use of slice multiplexing which permitted whole brain coverage at high spatial resolution (84 slices of 1.6 mm thickness). Radiofrequency power deposition was kept within regulatory limits by use of the power independent of number of slices (PINS) technique. A high in-plane spatial resolution of 1.5 mm was obtained, while image distortion was ameliorated by the use of in-plane parallel imaging techniques. Data from six subjects were obtained with a measurement time of just over 15 min per subject. A group level independent component (IC) analysis revealed 24 non-artefactual resting state networks, including those commonly found in standard acquisitions, as well as plausible networks for a broad range of regions. Signal was measured from regions commonly rendered inaccessible due to signal voids in gradient echo acquisitions. Dual regression was used to obtain spatial IC maps at the single subject level revealing exquisite localisation to grey matter that is consistent with a high degree of T(2)-weighting in the acquisition sequence. This technique hence holds great promise for both resting state and activation studies at 7 T.
本文展示了在 7T 下使用自旋回波 EPI 进行静息态 fMRI 的应用。通过使用切片复用技术，实现了 1860ms 的短重复时间，从而可以在高空间分辨率（1.6mm 厚的 84 个切片）下覆盖整个大脑。通过使用与切片数无关的功率（PINS）技术，将射频功率沉积控制在规定范围内。获得了 1.5mm 的高平面空间分辨率，并且通过使用平面内并行成像技术改善了图像失真。对 6 名受试者的数据进行了采集，每个受试者的测量时间仅超过 15 分钟。对受试者的组水平独立成分（IC）分析显示了 24 个非人为因素的静息态网络，包括标准采集中常见的网络，以及广泛区域的合理网络。信号是从由于梯度回波采集中的信号空洞而通常无法访问的区域测量的。双回归用于获得单个体水平的空间 IC 图，揭示了与采集序列中高度 T2 加权相一致的灰质的精细定位。因此，该技术在 7T 下的静息态和激活研究中具有很大的应用前景。
