International Neuroscience Institute, Hannover, Germany.
J Neurosurg. 2011 Dec;115(6):1087-93. doi: 10.3171/2011.7.JNS11495. Epub 2011 Aug 26.
The reliable preoperative visualization of facial nerve location in relation to vestibular schwannoma (VS) would allow surgeons to plan tumor removal accordingly and may increase the safety of surgery. In this prospective study, the authors attempted to validate the reliability of facial nerve diffusion tensor (DT) imaging-based fiber tracking in a series of patients with large VSs. Furthermore, the authors evaluated the potential of this visualization technique to predict the morphological shape of the facial nerve (tumor compression-related flattening of the nerve).
Diffusion tensor imaging and anatomical images (constructive interference in steady state) were acquired in a series of 22 consecutive patients with large VSs and postprocessed with navigational software to obtain facial nerve fiber tracking. The location of the cerebellopontine angle (CPA) part of the nerve in relation to the tumor was recorded during surgery by the surgeon, who was blinded to the results of the fiber tracking. A correlative analysis was performed of the imaging-based location of the nerve compared with its in situ position in relation to the VS.
Fibers corresponding to the anatomical location and course of the facial nerve from the brainstem to the internal auditory meatus were identified with the DT imaging-based fiber tracking technique in all 22 cases. The location of the CPA segment of the facial nerve in relation to the VS determined during surgery corresponded to the location of the fibers, predicted by the DT imaging-based fiber tracking, in 20 (90.9%) of the 22 patients. No DT imaging-based fiber tracking correlates were found with the 2 morphological types of the nerve (compact or flat).
The current study of patients with large VSs has shown that the position of the facial nerve in relation to the tumor can be predicted reliably (in 91%) using DT imaging-based fiber tracking. These are preliminary results that need further verification in a larger series.
可靠地预测前庭神经鞘瘤（VS）相关面神经位置，可使外科医生相应地规划肿瘤切除方案，从而提高手术安全性。在这项前瞻性研究中，作者尝试在一系列大型 VS 患者中验证基于面神经弥散张量（DT）成像的纤维追踪的可靠性。此外，作者评估了这种可视化技术预测面神经形态（肿瘤相关的面神经扁平化）的潜力。
在一系列 22 例大型 VS 患者中采集弥散张量成像和解剖图像（稳态构建性干扰），并使用导航软件对其进行后处理，以获得面神经纤维追踪。在手术过程中，外科医生记录神经桥小脑角（CPA）部分与肿瘤的位置，而对外科医生对纤维追踪结果进行盲法处理。对基于影像学的神经位置与神经与 VS 关系的原位位置进行了相关性分析。
在所有 22 例患者中，均采用基于 DT 成像的纤维追踪技术成功识别了从脑干到内听道的面神经解剖位置和走行的纤维。术中确定的面神经 CPA 段与 VS 的位置与基于 DT 成像的纤维追踪预测的纤维位置相对应，在 22 例患者中的 20 例（90.9%）中一致。未发现基于 DT 成像的纤维追踪与面神经的 2 种形态类型（致密型或扁平型）存在相关性。
本项针对大型 VS 患者的研究表明，使用基于 DT 成像的纤维追踪可可靠预测（准确率 91%）面神经与肿瘤的位置。这些是初步结果，需要在更大系列中进一步验证。
