An Ex Vivo Imaging Pipeline for Producing High-Quality and High-Resolution Diffusion-Weighted Imaging Datasets
An Ex Vivo Imaging Pipeline for Producing High-Quality and High-Resolution Diffusion-Weighted Imaging Datasets
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DOI：
10.1002/hbm.21043
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发表时间：
2011-04-01
影响因子：
4.8
通讯作者：
Sogaard, Lise V.
中科院分区：
文献类型：
--
作者：
Dyrby, Tim B.;Baare, William F. C.;Sogaard, Lise V.
扩散张量（DT）成像和相关的多纤维重建算法允许研究体内的微观结构，并通过纤维束成像，结构连接。虽然重建算法是有前途的成像工具，高质量的扩散加权成像（DWI）数据集的验证和确认的后处理和分析方法是缺乏的。临床体内DWI受到例如生理噪声和低信噪比的限制。在这里，我们对死后猪脑进行了一系列DWI测量，这些猪脑在神经解剖学复杂性上类似于人脑，以建立用于生成高质量DWI数据集的离体成像管道。灌注固定确保组织特征与体内条件相当。有三个主要结果：（i）热传导和不稳定的组织力学解释了DWI数据集中随时间变化的伪影，这些伪影在将脑组织定位在扫描仪中之后存在长达15小时;（ii）使用拟合的DT、q球和持续角结构磁共振成像算法，在近似于2，000和近似于8，000 s/mm（2）之间的任何b值，最佳值为4左右，000 s/mm（2），允许纤维方向的一致重建;（iii）死后脑组织中的扩散率测量值在3年内保持稳定。在这些结果的基础上，我们建立了一个优化的高质量和高分辨率DWI离体管道。流水线产生具有高水平组织结构细节的DWI数据集，例如显示大脑皮层中的两个平行水平边缘和海马中的多个边缘。我们得出结论，高质量的离体DWI可用于验证纤维重建算法，并补充组织学研究。《脑地图》32：544-563，2011年。(C)2010 Wiley-Liss，Inc.
Diffusion tensor (DT) imaging and related multifiber reconstruction algorithms allow the study of in vivo microstructure and, by means of tractography, structural connectivity. Although reconstruction algorithms are promising imaging tools, high-quality diffusion-weighted imaging (DWI) datasets for verification and validation of postprocessing and analysis methods are lacking. Clinical in vivo DWI is limited by, for example, physiological noise and low signal-to-noise ratio. Here, we performed a series of DWI measurements on postmortem pig brains, which resemble the human brain in neuroanatomical complexity, to establish an ex vivo imaging pipeline for generating high-quality DWI datasets. Perfusion fixation ensured that tissue characteristics were comparable to in vivo conditions. There were three main results: (i) heat conduction and unstable tissue mechanics accounted for time-varying artefacts in the DWI dataset, which were present for up to 15 h after positioning brain tissue in the scanner; (ii) using fitted DT, q-ball, and persistent angular structure magnetic resonance imaging algorithms, any b-value between similar to 2,000 and similar to 8,000 s/mm(2), with an optimal value around 4,000 s/mm(2), allowed for consistent reconstruction of fiber directions; (iii) diffusivity measures in the postmortem brain tissue were stable over a 3-year period. On the basis of these results, we established an optimized ex vivo pipeline for high-quality and high-resolution DWI. The pipeline produces DWI data sets with a high level of tissue structure detail showing for example two parallel horizontal rims in the cerebral cortex and multiple rims in the hippocampus. We conclude that high-quality ex vivo DWI can be used to validate fiber reconstruction algorithms and to complement histological studies. Hum Brain Mapp 32:544-563, 2011. (C) 2010 Wiley-Liss, Inc.