T2-weighted 3D fMRI using S2-SSFP at 7 tesla.
T2-weighted 3D fMRI using S2-SSFP at 7 tesla.
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DOI：
10.1002/mrm.22283
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发表时间：
2010-04
影响因子：
3.3
通讯作者：
Norris, David G.
中科院分区：
文献类型：
--
作者：
Barth, Markus;Meyer, Heiko;Kannengiesser, Stephan A. R.;Polimeni, Jonathan R.;Wald, Lawrence L.;Norris, David G.
在这项研究中，S2-SSFP（稳态自由进动）信号的灵敏度为功能性MRI（fMRI）在7特斯拉进行了研究。为了实现必要的时间分辨率，采用了沿沿着两个空间轴加速度的3D采集方案。基于S2-SSFP数据的激活图显示了与自旋回波回波平面成像（SE-EPI）相似的激活和灵敏度的空间定位，但数据可以以显著较低的功率沉积获得。通过平均z值估计的功能灵敏度对于SE-EPI与S2信号相比没有显著差异，但是对于S2信号略低（TR = 15 ms协议为6.74 ± 0.32，TR = 27 ms方案为7.51 ± 0.78），而使用相同激活体素的SE-EPI分别为7.49 ± 1.44和8.05 ± 1.67。与TR = 15 ms S2-SSFP方案（2.75%± 0.53%）相比，SE-EPI（2.37%± 0.18%）激活时这些体素的相对信号变化略低，并且显著低于TR = 27 ms方案（5.38% ± 1.28%），与模拟结果一致。长TR SSFP方案的大的相对信号变化可以通过来自多个相干途径的贡献和S2信号的低固有强度来解释。总之，全脑T2加权功能磁共振成像与可忽略的图像失真在7特斯拉是可行的，使用S2-SSFP序列和部分并行成像。
In this study the sensitivity of the S2-SSFP (steady-state free precession) signal for functional MRI (fMRI) at 7 Tesla was investigated. In order to achieve the necessary temporal resolution, a 3D acquisition scheme with acceleration along two spatial axes was employed. Activation maps based on S2-SSFP data showed similar spatial localisation of activation and sensitivity as spin-echo echo-planar imaging (SE-EPI) but data can be acquired with substantially lower power deposition. The functional sensitivity estimated by the average z-values was not significantly different for SE-EPI compared to the S2-signal, however slightly lower for the S2-signal (6.74 ± 0.32 for the TR = 15 ms protocol, and 7.51 ± 0.78 for the TR = 27 ms protocol) compared to SE-EPI (7.49 ± 1.44 and 8.05 ± 1.67) using the same activated voxels, respectively. The relative signal changes in these voxels upon activation were slightly lower for SE-EPI (2.37%± 0.18%) compared to the TR = 15 ms S2-SSFP protocol (2.75%± 0.53%) and significantly lower than the TR = 27 ms protocol (5.38% ± 1.28%) in line with simulations results. The large relative signal change for the long TR SSFP protocol can be explained by contributions from multiple coherence pathways, and the low intrinsic intensity of the S2 signal. In conclusion, whole-brain T2-weighted fMRI with negligible image distortion at 7 Tesla is feasible using the S2-SSFP sequence and partially parallel imaging.
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影响因子：
2.9
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