Inner ear high signal on non‑contrast 3D FLAIR imaging in patients with cerebrospinal fluid leaks: Association with dural/subdural changes and with audiovestibular symptoms.

BACKGROUND

Patients with spinal cerebrospinal fluid (CSF) leaks frequently experience audiovestibular symptoms. While gadolinium-enhanced MRI has been used to detect inner ear abnormalities, no reports have described findings on non-contrast MRI. We aimed to evaluate inner ear high signals on non-contrast three-dimensional (3D) fluid attenuated inversion recovery (FLAIR) imaging and their associations with dural/subdural findings and with audiovestibular symptoms.

METHODS

Twenty-one patients (42 ears) diagnosed with CSF leaks were retrospectively recruited. We evaluated inner ear signal intensity on non‑contrast 3D FLAIR imaging in the cochlea, vestibule, and semicircular canals (SCCs) bilaterally, and dural/subdural abnormalities (diffuse dural/subdural hyperintensity and diffuse pachymeningeal enhancement) on head MRI. Associations between inner ear signal and dural/subdural lesions, cochlear signal and auditory symptoms (hearing loss, tinnitus and ear fullness), and vestibular/SCC signal and vertigo were assessed using Fisher's exact test at the ear level and/or patient level.

RESULTS

Inner ear FLAIR hyperintensity was associated with dural/subdural lesions (p = 0.008). Although hearing loss and tinnitus correlated with cochlear hyperintensity in exploratory ear-level analyses (p = 0.009 and 0.003, respectively), only tinnitus remained significantly associated at the patient level. Inner ear hyperintensity showed no association with ear fullness or vertigo.

CONCLUSIONS

Inner ear hyperintensity on non-contrast 3D FLAIR imaging is observed in CSF leak patients and associates with dural/subdural lesions. Primary patient-level analysis reveals a correlation with tinnitus, while ear-level findings regarding hearing loss remain exploratory. These results may support the utility of non-contrast 3D FLAIR imaging for evaluating inner ear pathology in CSF leak patients.