Skull Base Multi-disciplinary Unit, Department of Neurosurgery B, Neurological Hospital Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.
Department of Anatomy, University of Lyon 1, Lyon, France.
Neurosurgery. 2019 Feb 1;84(2):313-325. doi: 10.1093/neuros/nyy229.
Diffusion imaging tractography caught the attention of the scientific community by describing the white matter architecture in vivo and noninvasively, but its application to small structures such as cranial nerves remains difficult. The few attempts to track cranial nerves presented highly variable acquisition and tracking settings.
To conduct and present a targeted review collecting all technical details and pointing out challenges and solutions in cranial nerve tractography.
A "targeted" review of the scientific literature was carried out using the MEDLINE database. We selected studies that reported how to perform the tractography of cranial nerves, and extracted the following: clinical context; imaging acquisition settings; tractography parameters; regions of interest (ROIs) design; and filtering methods.
Twenty-one published articles were included. These studied the optic nerves in suprasellar tumors, the trigeminal nerve in neurovascular conflicts, the facial nerve position around vestibular schwannomas, or all cranial nerves. Over time, the number of MRI diffusion gradient directions increased from 6 to 101. Nine tracking software packages were used which offered various types of tridimensional display. Tracking parameters were disparately detailed except for fractional anisotropy, which ranged from 0.06 to 0.5, and curvature angle, which was set between 20° and 90°. ROI design has evolved towards a multi-ROI strategy. Furthermore, new algorithms are being developed to avoid spurious tracts and improve angular resolution.
This review highlights the variability in the settings used for cranial nerve tractography. It points out challenges that originate both from cranial nerve anatomy and the tractography technology, and allows a better understanding of cranial nerve tractography.
扩散成像轨迹描记术通过描述活体和非侵入性的白质结构引起了科学界的关注，但将其应用于颅神经等小结构仍然具有挑战性。少数追踪颅神经的尝试提出了高度可变的采集和追踪设置。
进行并呈现一项有针对性的综述，收集所有技术细节，并指出颅神经轨迹描记术的挑战和解决方案。
使用 MEDLINE 数据库对科学文献进行了“有针对性”的回顾。我们选择了报告如何进行颅神经轨迹描记术的研究，并提取了以下内容：临床背景；成像采集设置；轨迹描记术参数；感兴趣区（ROI）设计；和过滤方法。
共纳入 21 篇已发表的文章。这些文章研究了鞍上肿瘤中的视神经、神经血管冲突中的三叉神经、前庭神经鞘瘤周围的面神经位置，或所有颅神经。随着时间的推移，MRI 扩散梯度方向的数量从 6 个增加到 101 个。使用了 9 个跟踪软件包，提供了各种类型的三维显示。跟踪参数各不相同，除了各向异性分数（范围从 0.06 到 0.5）和曲率角（设置在 20°到 90°之间）之外。ROI 设计已经发展到多 ROI 策略。此外，正在开发新的算法来避免虚假轨迹并提高角分辨率。
本综述强调了颅神经轨迹描记术设置的可变性。它指出了源自颅神经解剖结构和轨迹描记术技术的挑战，并有助于更好地理解颅神经轨迹描记术。
