Zolal Amir, Juratli Tareq A, Podlesek Dino, Rieger Bernhard, Kitzler Hagen H, Linn Jennifer, Schackert Gabriele, Sobottka Stephan B
Department of Neurosurgery and Outpatient Clinic, Carl Gustav Carus Medical Faculty, University of Technology, Dresden, Germany.
Department of Neurosurgery and Outpatient Clinic, Carl Gustav Carus Medical Faculty, University of Technology, Dresden, Germany.
World Neurosurg. 2017 Nov;107:47-53. doi: 10.1016/j.wneu.2017.07.102. Epub 2017 Jul 25.
Multiple recent studies have reported on diffusion tensor-based fiber tracking of cranial nerves in vestibular schwannoma, with conflicting results as to the accuracy of the method and the occurrence of cochlear nerve depiction. Probabilistic nontensor-based tractography might offer advantages in terms of better extraction of directional information from the underlying data in cranial nerves, which are of subvoxel size.
Twenty-one patients with large vestibular schwannomas were recruited. The probabilistic tracking was run preoperatively and the position of the potential depictions of the facial and cochlear nerves was estimated postoperatively by 3 independent observers in a blinded fashion. The true position of the nerve was determined intraoperatively by the surgeon. Thereafter, the imaging-based estimated position was compared with the intraoperatively determined position. Tumor size, cystic appearance, and postoperative House-Brackmann score were analyzed with regard to the accuracy of the depiction of the nerves.
The probabilistic tracking showed a connection that correlated to the position of the facial nerve in 81% of the cases and to the position of the cochlear nerve in 33% of the cases. Altogether, the resulting depiction did not correspond to the intraoperative position of any of the nerves in 3 cases.
In a majority of cases, the position of the facial nerve, but not of the cochlear nerve, could be estimated by evaluation of the probabilistic tracking results. However, false depictions not corresponding to any nerve do occur and cannot be discerned as such from the image only.
近期多项研究报道了基于扩散张量的前庭神经鞘瘤中颅神经纤维追踪情况，但在该方法的准确性以及耳蜗神经描绘的发生率方面结果相互矛盾。基于概率的非张量纤维束成像可能在从亚体素大小的颅神经基础数据中更好地提取方向信息方面具有优势。
招募了21例患有大型前庭神经鞘瘤的患者。术前进行概率追踪，术后由3名独立观察者以盲法估计面神经和耳蜗神经可能的描绘位置。术中由外科医生确定神经的真实位置。此后，将基于成像的估计位置与术中确定的位置进行比较。分析肿瘤大小、囊性外观和术后House-Brackmann评分与神经描绘准确性的关系。
概率追踪显示，81%的病例中存在与面神经位置相关的连接，33%的病例中存在与耳蜗神经位置相关的连接。总共，在3例病例中，最终的描绘与任何神经的术中位置均不相符。
在大多数情况下，通过评估概率追踪结果可以估计面神经的位置，但不能估计耳蜗神经的位置。然而，确实会出现与任何神经都不对应的错误描绘，并且仅从图像中无法识别此类情况。
