Behan Brendan, Chen David Q, Sammartino Francesco, DeSouza Danielle D, Wharton-Shukster Erika, Hodaie Mojgan
Division of Brain, Imaging and Behaviour - Systems Neuroscience, Krembil Institute, University Health Network, Toronto, ON, Canada.
Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, Toronto, ON, Canada.
Front Neurosci. 2017 Oct 9;11:554. doi: 10.3389/fnins.2017.00554. eCollection 2017.
Diffusion-weighted imaging (DWI)-based tractography has gained increasing popularity as a method for detailed visualization of white matter (WM) tracts. Different imaging techniques, and more novel, advanced imaging methods provide significant WM structural detail. While there has been greater focus on improving tract visualization for larger WM pathways, the relative value of each method for cranial nerve reconstruction and how this methodology can assist surgical decision-making is still understudied. Images from 10 patients with posterior fossa tumors (4 male, mean age: 63.5), affecting either the trigeminal nerve (CN V) or the facial/vestibular complex (CN VII/VIII), were employed. Three distinct reconstruction methods [two tensor-based methods: single diffusion tensor tractography (SDT) (3D Slicer), eXtended streamline tractography (XST), and one fiber orientation distribution (FOD)-based method: streamline tractography using constrained spherical deconvolution (CSD)-derived estimates (MRtrix3)], were compared to determine which of these was best suited for use in a neurosurgical setting in terms of processing speed, anatomical accuracy, and accurate depiction of the relationship between the tumor and affected CN. Computation of the tensor map was faster when compared to the implementation of CSD to provide estimates of FOD. Both XST and CSD-based reconstruction methods tended to give more detailed representations of the projections of CN V and CN VII/VIII compared to SDT. These reconstruction methods were able to more accurately delineate the course of CN V and CN VII/VIII, differentiate CN V from the cerebellar peduncle, and delineate compression of CN VII/VIII in situations where SDT could not. However, CSD-based reconstruction methods tended to generate more invalid streamlines. XST offers the best combination of anatomical accuracy and speed of reconstruction of cranial nerves within this patient population. Given the possible anatomical limitations of single tensor models, supplementation with more advanced tensor-based reconstruction methods might be beneficial.
基于扩散加权成像（DWI）的纤维束成像作为一种详细可视化白质（WM）纤维束的方法越来越受欢迎。不同的成像技术，以及更新颖、更先进的成像方法提供了显著的WM结构细节。虽然人们更加关注改善较大WM通路的纤维束可视化，但每种方法在颅神经重建中的相对价值以及该方法如何辅助手术决策仍未得到充分研究。我们使用了10例后颅窝肿瘤患者（4例男性，平均年龄：63.5岁）的图像，这些肿瘤影响三叉神经（CN V）或面/前庭复合体（CN VII/VIII）。比较了三种不同的重建方法[两种基于张量的方法：单扩散张量纤维束成像（SDT）（3D Slicer）、扩展流线纤维束成像（XST），以及一种基于纤维取向分布（FOD）的方法：使用约束球面反卷积（CSD）导出估计值的流线纤维束成像（MRtrix3）]，以确定就处理速度、解剖准确性以及肿瘤与受影响的CN之间关系的准确描绘而言，哪种方法最适合用于神经外科手术。与实施CSD以提供FOD估计值相比，张量图的计算速度更快。与SDT相比，基于XST和CSD的重建方法往往能更详细地显示CN V和CN VII/VIII的投影。这些重建方法能够更准确地描绘CN V和CN VII/VIII的走行，将CN V与小脑脚区分开来，并在SDT无法做到的情况下描绘CN VII/VIII的受压情况。然而，基于CSD的重建方法往往会产生更多无效流线。在该患者群体中，XST在解剖准确性和颅神经重建速度方面提供了最佳组合。鉴于单张量模型可能存在的解剖学局限性，补充更先进的基于张量的重建方法可能是有益的。
