High-fidelity, high-isotropic-resolution diffusion imaging through gSlider acquisition with B1+and T1 corrections and integrated ΔB0/Rx shim array
High-fidelity, high-isotropic-resolution diffusion imaging through gSlider acquisition with B1+and T1 corrections and integrated ΔB0/Rx shim array
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DOI：
10.1002/mrm.27899
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发表时间：
2019-08-01
影响因子：
3.3
通讯作者：
Setsompop, Kawin
中科院分区：
文献类型：
--
作者：
Liao, Congyu;Stockmann, Jason;Setsompop, Kawin
目的提出B1+和T-1校正以及动态多线圈匀场方法，以提高高分辨率广义切片抖动增强分辨率（gSlider）扩散成像的保真度。方法采用B1+不均匀性和T-1恢复信息的扩展重建方法，以消除短重复时间（TR）gSlider采集中的板状边界伪影。使用多线圈集成Delta B-0/Rx匀场阵列的逐板动态B-0匀场和使用虚拟线圈GRAPPA实现的高平面内加速度（R-inplane = 4）也被纳入1 mm各向同性分辨率gSlider采集/重建框架，以实现与单次激发回波平面成像（EPI）相比几何失真的显著降低。结果与用于短TR采集的标准gSlider重建管道相比，所提出的B1+和T-1校正减轻了板边界伪影。与传统的全局二阶匀场相比，动态匀场提供了>50%的几何失真减少。一毫米各向同性分辨率扩散数据表明，典型的有问题的颞叶和额叶的大脑可以成像与高几何保真度使用动态匀场。结论与传统的gSlider采集和重建相比，提出的B1+和T-1校正和局部场控制大大提高了高各向同性分辨率扩散成像的保真度，减少了板边界伪影和几何失真。这使得使用3 T临床扫描仪能够在20分钟内进行具有64个扩散方向的高保真度全脑1 mm各向同性扩散成像。
Purpose B1+ and T-1 corrections and dynamic multicoil shimming approaches were proposed to improve the fidelity of high-isotropic-resolution generalized slice-dithered enhanced resolution (gSlider) diffusion imaging. Methods An extended reconstruction incorporating B1+ inhomogeneity and T-1 recovery information was developed to mitigate slab-boundary artifacts in short-repetition time (TR) gSlider acquisitions. Slab-by-slab dynamic B-0 shimming using a multicoil integrated Delta B-0/Rx shim array and high in-plane acceleration (R-inplane = 4) achieved with virtual-coil GRAPPA were also incorporated into a 1-mm isotropic resolution gSlider acquisition/reconstruction framework to achieve a significant reduction in geometric distortion compared to single-shot echo planar imaging (EPI). Results The slab-boundary artifacts were alleviated by the proposed B1+ and T-1 corrections compared to the standard gSlider reconstruction pipeline for short-TR acquisitions. Dynamic shimming provided >50% reduction in geometric distortion compared to conventional global second-order shimming. One-millimeter isotropic resolution diffusion data show that the typically problematic temporal and frontal lobes of the brain can be imaged with high geometric fidelity using dynamic shimming. Conclusions The proposed B1+ and T-1 corrections and local-field control substantially improved the fidelity of high-isotropic-resolution diffusion imaging, with reduced slab-boundary artifacts and geometric distortion compared to conventional gSlider acquisition and reconstruction. This enabled high-fidelity whole-brain 1-mm isotropic diffusion imaging with 64 diffusion directions in 20 min using a 3T clinical scanner.