The Study Of Reconstruction Of Facial Nerve By Diffusion Tensor Imaging-based Fiber Tracking

Objective?To evaluate the feasibility and accuracy of the reconstruction of facialnerve by diffusion tensor imaging-based fiber tracking to find relative positionsbetween facial nerves and schwannomas in patients with acoustic neuromas.Methods?The clinical data of patients treated in neurosurgery department ofPLAGH between November,2012and July,2013were collected. Patients withlesions in cerebellopontine angles?primary diagnosed as acoustic neuroma, andunderwent microsurgical removal in our department were included. The exclusioncriteria included a history of intracranial surgery or radiotherapy, and a pathologicaldiagnosis of non-schwannoma.A total of15patients were enrolled. Preoperative MRIexamination were performed at a3.0Tesla signal scanner, including routine andenhanced scans,3D FIESTA-C, and DTI. DTI-based fiber tracking were performedwith3D Slicer software. The ROI was precisely selected including the internalauditory canal and the REZ of facial nerve according to3D FIESTA-C images.Tracking the fibers through both two ROIs, then reconstructing the targeted tumorsand facial nerves to acquire the information of distributions of facial nerve andrelative position between facial nerves and the tumors. There are six patterns ofposition relations between the cisternal segment of the facial nerve and the tumor,including the anterior-superior, the anterior-middle?the anterior-inferior,the superiorpole, the inferior pole, and the posterior portions of the tumor. The accuracy of thereconstructions of the facial nerve was verified in operation.Results?Preoperative reconstructions of facial nerves by using DTI-FT waspossible in14of15patients, and the branches of facial nerve and its relative positionwith the tumor could be observed. Facial nerve locations reconstructed agreed to surgical observing in13of14cases. The facial nerves located in the belly side oftumors in all of the13patients (anterior-superior7cases, anterior-middle1case,anterior-inferior3cases, inferior-pole2cases).Conclusion?Reconstruction of the facial nerve by DTI-FT has certain feasibilityin patients with acoustic neuromas, and it is helpful to obtain a preoperative visualobservation to the positions of the facial nerves in relation to acoustic neuromas. Andit can also help surgeons to locate the facial nerves in operation, minimize the injuriesdone to the nerves and accelerate operation process. But this technology has itslimitation and uncertainty in the reconstructions of facial nerves, more studies areneeded to verify its accuracy.