The endolymphatic sac in patients with Ménière's disease: correlation between the MRI and the surgical findings.

The endolymphatic sac (ES) is thought to have close relations to pathogenesis of endolymphatic hydrops. Here is reported a retrospective study of 41 patients (42 ears) with Meniere's disease who underwent MRI prior to endolymphatic sac surgery. Based on proton-density weighted image (PDI) and T2-weighted image (T2), the ES including an endolymphatic duct (ED) were estimated whether it was detectable or not. Fourteen ESs were detected on both images (Group A), 14 ESs were detected only on PDI (Group B), and the remaining 14 ESs were not detected on either image (Group D). The actual shape of the sac, obtained from surgical findings, was classified into three (normoplastic, atrophic, invisible). Seventeen ears showed normoplastic ESs and 14 showed atrophic ESs. ES was not detected in 11 ears during surgery, and these findings were compared with image classification. From the study data, normoplastic ESs tend to be observed on both images whereas atrophic or invisible sacs were hardly observed on T2. This classification of ES on MRI was thought to correlate with surgical findings and this correlation was statistically significant (Spearman's rank correlation coefficient. r(s) = 0.58, p < 0.01).