One Cause of Sensorineural Hearing Loss for Meniere's disease, Otosyphilis, and Enlarged Vestibular Aqueduct Syndrome from MR findings

Objectives/Hypothesis To evaluate conditions of the endolymphatic duct and sac of normal subjects, Meniere's disease (MD), late congenital otosyphilis, and enlarged vestibular aqueduct syndrome (EVAS) from high‐resolution MR imaging. Although these diseases present similar clinical symptoms, the basic etiology is veiled. Comparing their pathological evidence with these MR features results in one hypothesis of the causes of MD, late congenital otosyphilis, and EVAS. Study Design Retrospective study Materials and Method 10 normal ears, 10 unilateral MD, 1 unilateral EVAS, and 1 late congenital Otosyphilis underwent 1.5T MR scanner. The scan sequences were as follows; SE (T1‐W, Proton Density, and T2‐W), FISP (T2‐W) and FLASH (Proton Density). Results Although the normal endolymphatic duct and sac were depicted relatively low signal in all sequences, the rugose portion of the sac was imaged as a low signal constriction. In MD, there were two patterns imaging. One lacked imaging of the endolymphatic duct. In the other, there was stenosis in the part of the rugose portion. In EVAS, the endolymphatic duct and sac showed enlargement with high signal fluid on T2‐WI. In the late congenital syphilis, the enlarged endolymphatic duct and sac compounded with the soft tissue irregular intensified substances were depicted. Conclusions Under normal conditions, the normal endolymphatic duct and sac are depicted in low signal intensity by all MR imaging sequences. That is, if a certain part will be depicted as a high signal, the lesion will be considered as an abnormality. Hence, in EVAS, this fact indicates that the high signal endolymphatic and duct in T2‐WI are abnormal status. This condition will be caused by stagnation of the endolymph. The stagnation is the inhibition of the endolymphatic flow itself. The symptoms of otosyphilis will be caused that the endolymphatic duct and sac are occluded by the microgummata and fibrotic substances, and the endolymphatic flow is obstructed. However, In MD, the causes are complicated in this study. There are two possible obstructive lesions in the endolymphatic duct and sac. One seems to be deeper than the sinus in the proximal part of the endolymphatic duct, because the endolymphatic duct cannot be depicted in MR imaging. The other will be at the rugose portion of the sac. In the later pattern, the endolymphatic duct may be imaged at parts with high intensified spot on T2‐WI. Any patient with unexplained sudden deafness should be screened for syphilis. Support or Funding InformationConflict of Interest The author of this manuscript declares no relationship with any companies, whose products or services may be related the subject matter of the articlcle. Funding: The author states that this work has not received any fundings.