In Vivo Volumetric Analysis of Endolymphatic Hydrops in Ménière Disease Using 7-Tesla MRI and Advanced
Syed A Ahmad1, Joon Soo Kim1, Diane Jung2
1Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD.
Objective:
To evaluate endolymphatic hydrops (EH) in patients with Meniere disease (MD) using high-resolution 7-tesla (7T) MRI volumetry with the goal of identifying anatomic differences that might clarify MD's etiology and inform therapeutic strategies.
Study Design:
Prospective cohort study.
Setting:
Tertiary referral center.
Patients:
Twelve adults with MD and 5 healthy controls met the inclusion criteria.
Interventions:
Participants underwent 7T MRI, including axial T2-weighted and 3D-FLAIR sequences, before and 4 hours after intravenous gadolinium-based contrast agent administration. Images were coregistered and subtracted to identify endolymph as a negative signal, followed by blinded manual segmentation.
Main Outcome Measures:
Volumetric measurements of the membranous labyrinth [utricle+semicircular canals duct (SCC), saccule, cochlear duct, and total endolymph].
Results:
Fifteen MD-affected ears were compared with 10 healthy control ears. Median endolymph volumes were significantly larger in MD-affected ears in the utricle and SCC (99.53 vs. 55.29 mm 3 , P =0.033) but not in the saccule ( P =0.56) or cochlear duct ( P =0.21). The ratio of endolymph to total fluid inner ear fluid was also greater in MD-affected ears compared with controls (62.3% vs. 44.0%). Unaffected MD ears did not differ from their affected counterparts across compartments.
Conclusions:
In vivo 7T MRI volumetry revealed significantly greater EH in the utricle and SCC of MD-affected ears versus controls, demonstrating its utility for characterizing EH and guiding more precise diagnostics and therapies. Future work must refine methods to reliably distinguish the utricle-saccule boundary-through improved imaging protocols or automated segmentation-to assess saccular hydrops in living patients.
