RT Journal Article
SR Electronic
T1 Normal Facial Nerve Enhancement on Volumetric Interpolated Breath-Hold Examination MRI Sequence
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
DO 10.3174/ajnr.A8592
A1 Nawaz, Nanjiba
A1 Desai, Amit B.
A1 Bhatt, Alok A.
YR 2025
UL http://www.ajnr.org/content/early/2025/05/15/ajnr.A8592.abstract
AB BACKGROUND AND PURPOSE: Enhancement of the facial nerve can be seen on MRI due to its rich arteriovenous plexus. Classically, enhancement of the facial nerve beyond the geniculate ganglion has been described as a normal finding, while enhancement of the canalicular and labyrinthine segments is considered abnormal. We hypothesize facial nerve enhancement of the canalicular and labyrinthine segments is a normal finding on the postcontrast T1-weighted, fat-saturated volumetric interpolated breath-hold examination (VIBE) sequence on both 1.5T and 3T MRI scanners.MATERIALS AND METHODS: Fifty patients without facial nerve symptoms undergoing MRI by using the internal auditory canal protocol were identified at our institution, 25 cases on a 1.5T scanner and 25 cases on a 3T scanner; a total of 100 facial nerves. Presence or absence of enhancement of the facial nerve segments on the postcontrast T1-weighted, fat-saturated VIBE sequence were independently analyzed by 2 neuroradiologists.RESULTS: On 1.5T, of 50 facial nerves evaluated, percentage of nerves with enhancement at each segment was as follows: 80% canalicular, 92% labyrinthine, 100% tympanic, 100% mastoid, and 80% intraparotid. On 3T, of 50 facial nerves evaluated, percentage of nerves with enhancement at each segment was as follows: 60% canalicular, 84% labyrinthine, 98% tympanic, 100% mastoid, and 93% intraparotid.CONCLUSIONS: Enhancement of the canalicular and labyrinthine segments of the facial nerve is a normal finding on the postcontrast, T1-weighted, fat-saturated VIBE sequence. Careful attention to clinical history and asymmetry should be considered before calling abnormality of the facial nerve.IACinternal auditory canalSPACESampling Perfection with Application optimized Contrast by using different flip-angle EvolutionVIBEvolumetric interpolated breath-hold examination