Ultra-high spatial resolution BOLD fMRI in humans using combined segmented-accelerated VFA-FLEET with a recursive RF pulse design.
Ultra-high spatial resolution BOLD fMRI in humans using combined segmented-accelerated VFA-FLEET with a recursive RF pulse design.
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DOI：
10.1002/mrm.28415
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发表时间：
2021-01
影响因子：
3.3
通讯作者：
Polimeni JR
中科院分区：
文献类型：
--
作者：
Berman AJL;Grissom WA;Witzel T;Nasr S;Park DJ;Setsompop K;Polimeni JR
通过开发用于超高分辨率功能磁共振成像的多镜头分段 EPI 来减轻单镜头 EPI 的空间编码限制，减少对象运动和呼吸产生的重影伪影。分段 EPI 可以减少读出持续时间并减少加速因子，但是，分段采集之间经过的时间（以秒为单位）可能会导致间歇性重影，从而限制了其在 fMRI 中的使用。在这里，“FLEET”片段排序（其中片段在切片之前循环）与可变翻转角级数（VFA-FLEET）相结合，以提高片段间保真度并最大化 fMRI 信号。缩放每个分段的正弦脉冲翻转角 (VFA-FLEET-Sinc) 会产生不一致的切片轮廓和重影，因此，开发了递归 Shinnar-Le Roux (SLR) RF 脉冲设计 (VFA-FLEET-SLR)，为每个分段生成独特的脉冲，这些脉冲共同产生一致的切片轮廓和信号。在 3 T 和 7 T 下将 VFA-FLEET-SLR 的时间稳定性与传统分段 EPI 和 VFA-FLEET-Sinc 进行比较。与传统分段和 VFA-FLEET-Sinc 相比，VFA-FLEET-SLR 的间歇性重影和稳定重影均有所减少，从而提高了图像质量，同时在时间 SNR 方面做出了较小的牺牲。将 VFA-FLEET-SLR 与加速相结合，我们在 7 T 下实现了 0.6 毫米各向同性采集（无需变焦成像或部分傅立叶），展示了对视觉刺激的 BOLD 响应的可靠检测。为了抵消分段导致的重复时间增加，使用射频编码控制混叠演示了同步多切片 VFA-FLEET-SLR。采用递归射频脉冲设计的 VFA-FLEET 支持低伪影和空间模糊水平的采集，从而能够以以前无法访问的空间分辨率和“全脑”视场进行功能磁共振成像。
To alleviate the spatial encoding limitations of single-shot EPI by developing multi-shot segmented EPI for ultra-high-resolution fMRI with reduced ghosting artifacts from subject motion and respiration. Segmented EPI can reduce readout duration and reduce acceleration factors, however, the time elapsed between segment acquisitions (on the order of seconds) can result in intermittent ghosting, limiting its use for fMRI. Here, “FLEET” segment ordering—where segments are looped over before slices—was combined with a variable flip angle progression (VFA-FLEET) to improve inter-segment fidelity and maximize signal for fMRI. Scaling a sinc pulse’s flip angle for each segment (VFA-FLEET-Sinc) produced inconsistent slice profiles and ghosting, therefore, a recursive Shinnar-Le Roux (SLR) RF pulse design was developed (VFA-FLEET-SLR) to generate unique pulses for every segment that together produce consistent slice profiles and signals. The temporal stability of VFA-FLEET-SLR was compared against conventional-segmented EPI and VFA-FLEET-Sinc at 3 T and 7 T. VFA-FLEET-SLR showed reductions in both intermittent and stable ghosting compared to conventional-segmented and VFA-FLEET-Sinc, resulting in improved image quality with a minor trade-off in temporal SNR. Combining VFA-FLEET-SLR with acceleration, we achieved a 0.6-mm isotropic acquisition at 7 T—without zoomed imaging or partial Fourier—demonstrating reliable detection of BOLD responses to a visual stimulus. To counteract the increased repetition time from segmentation, simultaneous multi-slice VFA-FLEET-SLR was demonstrated using RF-encoded controlled aliasing. VFA-FLEET with a recursive RF pulse design supports acquisitions with low levels of artifact and spatial blur, enabling fMRI at previously inaccessible spatial resolutions with a “full-brain” field of view.
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影响因子：
16.2
作者：
Goense J;Merkle H;Logothetis NK
通讯作者：
Logothetis NK
影响因子：
5.7
作者：
Blazejewska, Anna, I;Fischl, Bruce;Polimeni, Jonathan R.
通讯作者：
Polimeni, Jonathan R.
影响因子：
5.7
作者：
Chen, Nan-kuei;Guidon, Arnaud;Chang, Hing-Chiu;Song, Allen W.
通讯作者：
Song, Allen W.
影响因子：
3.7
作者：
Feinberg DA;Moeller S;Smith SM;Auerbach E;Ramanna S;Gunther M;Glasser MF;Miller KL;Ugurbil K;Yacoub E
通讯作者：
Yacoub E
影响因子：
16.2
作者：
Cheng, K;Waggoner, RA;Tanaka, K
通讯作者：
Tanaka, K