Ongoing Discrepancy Between Unilateral Meniere's Disease and Bilateral Endolymphatic Hydrops on Hydrops MRI

In the era of Hydrops MRI, a clinical dilemma has emerged: while Meniere's disease (MD) is diagnosed unilaterally, Hydrops MRI demonstrates endolymphatic hydrops (EH) bilaterally. This study aims to clarify this ongoing discrepancy. Fifty-six MD patients underwent an inner ear test battery followed by 3 T Hydrops MRI. Eight unilateral MD patients with EH on both ears were classified as Group A and subdivided into Groups A1 (symptomatic EH on the affected ear, n = 8 ears) and A2 (asymptomatic EH on the opposite unaffected ear, n = 8 ears). Another 48 unilateral MD patients with EH on one ear only were referred to Group B and were subdivided into Group B1 (present EH, n = 48 ears) and Group B2 (absent EH, n = 48 ears). Both Groups A1 and B1 showed a significantly declining sequence of abnormality rates running from audiometry, cervical, and ocular vestibular-evoked myogenic potential tests to caloric test. However, such a declining trend was not observed in Groups A2 and B2. Significant differences in the abnormality rates of audiometry were noted in Groups A1 (88%) versus A2 (0) and Groups B1 (94%) versus B2 (27%). Four (50%) out of eight ears in Group A2 progressed to MD after a mean interval of 4 ± 2 years. If Hydrops MRI identifies EH in both ears of a unilateral MD patient, monitoring cochlear symptoms, hearing thresholds, and imaging findings in the opposite (unaffected) ear may help predict the progression from unilateral MD to bilateral MD. 4.