High-resolution MR imaging of enlarged eudolymphatic duct and sac syndrome using SD-FastASE: Volume and signal-intensity measurement of the endolymphatic duct and sac, and area measurement of the cochlear modiolus

INTRODUCTION: Large vestibular aqueduct syndrome, or enlarged endolymphatic duct (EED) and sac (EFS) syndrome, is an inner ear malformation which manifests itself as progressive sensorineural hearing loss starting in infancy or childhood. The deformity of the endolymphatic duct and sac is congenital: however, the hearing loss that develops in this syndrome is acquired. A characteristic feature is that hearing loss related to the large endolymphatic duct and sac is triggered by minor head trauma. Although, the true etiology of the hearing loss observed in this syndrome remains unknown, a variety of pathophysiological theories have been proposed. To investigate the pathophysiology of the progressive sensorineural hearing loss in EED and EFS syndrome, the volumes of the EED and EFS, the diameter of the EED, the area of the cochlear modiolus, and the signal intensities of the EED and EES were measured on high-resolution MR images, and the findings obtained were compared against the degree of hearing loss as assessed by audiograms.