Three-dimensional double echo steady state with water excitation MR imaging of facial nerve at 1.5T: A preliminary study / 中国医学影像技术

ABSTRACT

Objective To assess the value of three-dimensional double echo steady state with water excitation (3D-DESSwe) MR sequence in depicting the normal anatomy of facial nerve. Methods 3D-DESSwe MR sequence was performed in 15 healthy volunteers on a 1.5T MR. The 3D datasets obtained were constructed in relation to the course of the facial nerve using multi-planar reconstruction (MPR) and thin slice maximum intensity projection (MIP) programs, and the images acquired were compared with anatomical textbook diagrams. Two doctors analyzed the images in collaboration and recorded on an arbitrary scale of 0-2 grades (grade 2, homogeneity and facial nerve identified with certainty;grade 1, mild inhomogeneity and facial nerve probably identified;grade 0, severe inhomogeneity and facial nerve not identified). Results In all subjects, 3D-DESSwe images provided reliable definition of the normal facial nerve anatomy bilaterally and high contrast between the facial nerve and adjacent structures were obtained. The cisternal segment of facial nerve showed high signal intensity while the moving CSF flow surrounding it showed low signal intensity. The internal auditory canal (IAC) segment of facial nerve showed relatively low signal intensity while the stationary CSF surrounding it showed high signal intensity. The labyrinthine, tympanic, mastoid and extracranial segments of facial nerve showed high signal intensity while the bone and soft tissue surrounding it showed low signal intensity, and parts of facial nerve branches could be demonstrated. Conclusion 3D-DESSwe sequence can display the complete course of the normal facial nerve, especially for the intratemporal and extracranial parts.