High-resolution MRI of the intraparotid facial nerve based on a microsurface coil and a 3D reversed fast imaging with steady-state precession DWI sequence at 3T.

BACKGROUND AND PURPOSE 3D high-resolution MR imaging can provide reliable information for defining the exact relationships between the intraparotid facial nerve and adjacent structures. The purpose of this study was to explore the clinical value of using a surface coil combined with a 3D-PSIF-DWI sequence in intraparotid facial nerve imaging. MATERIALS AND METHODS Twenty-one healthy volunteers underwent intraparotid facial nerve scanning at 3T by using the 3D-PSIF-DWI sequence with both the surface coil and the head coil. Source images were processed with MIP and MPR to better delineate the intraparotid facial nerve and its branches. In addition, the SIR of the facial nerve and parotid gland was calculated. The number of facial nerve branches displayed by these 2 methods was calculated and compared. RESULTS The display rates of the main trunk, divisions (cervicofacial, temporofacial), and secondary branches of the intraparotid facial nerve were 100%, 97.6%, and 51.4% by head coil and 100%, 100%, and 83.8% by surface coil, respectively. The display rate of secondary branches of the intraparotid facial nerve by these 2 methods was significantly different (P < .05). The SIRs of the intraparotid facial nerve/parotid gland in these 2 methods were significantly different (P < .05) at 1.37 ± 1.06 and 1.89 ± 0.87, respectively. CONCLUSIONS The 3D-PSIF-DWI sequence combined with a surface coil can better delineate the intraparotid facial nerve and its divisions than when it is combined with a head coil, providing better image contrast and resolution. The proposed protocol offers a potentially useful noninvasive imaging sequence for intraparotid facial nerve imaging at 3T.