Computed tomographic analysis of the intratemporal facial nerve and facial nerve neuromas.
High-resolution computed tomography (HRCT) has replaced multidirectional tomography in the detailed analysis of the temporal bone because of its excellent resolution of fine bony detail. Small soft-tissue masses not discernible on plain tomograms are easily seen using HRCT. Unsuspected early disease which has not caused recognizable bone erosion in also demonstrable by HRCT. Last but not least, the amount of radiation received by a patient as a result of HRCT is considerably less. We illustrate the normal course of the facial nerve through the temporal bone, its anatomical relationship to various adjacent structures, and the numerous branches given off during its course through the temporal bone. The clinical features of facial nerve neuromas (schwannomas) depend on their location and include facial nerve weakness or paralysis, otalgia or facial pain, hearing loss or imbalance, and loss of taste sensation. HRCT allows the identification of a soft-tissue mass along the course of the facial nerve, with its bony canal usually enlarged by the mass. Pressure erosion of the underlying bone is often noted and erosion of the ossicles may be demonstrated in the case of middle ear involvement. The importance of both clinical and radiological correlation cannot be overemphasized in the discovery of these tumors.
Shankar
L
L
Department of Diagnostic Imaging; St. Joseph's Health Centre, Toronto, Ontario.
Hawke
M
M
Leekam
R N
RN
Rutka
J
J
D000328:Adult; D003390:Cranial Nerve Neoplasms / Q000000981:diagnostic imaging*; D007758:Ear, Inner / Q000294:innervation; D004432:Ear, Middle / Q000294:innervation; D005154:Facial Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D005155:Facial Nerve Diseases / Q000000981:diagnostic imaging*; D005158:Facial Paralysis / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008416:Mastoid / Q000294:innervation; D009463:Neuroma / Q000000981:diagnostic imaging*; D013701:Temporal Bone / Q000294:innervation*; D014057:Tomography, X-Ray Computed / Q000379:methods*