[Sudden onset hearing loss: imaging work-up]

Sudden onset hearing loss is idiopathic. It occurs in less than 24 h and spontaneously resolves within 15 days in two thirds of cases. Imaging is performed to exclude other causes of sudden onset hearing loss (vestibular schwannoma, vertebral artery dissection, stroke) and evaluate the inner ear structures. A few anatomical anomalies have been associated with an increased risk of hearing loss. Morphological anomalies involved the following structures in decreasing order of frequency: lateral semicircular canal (hypoplasia and dilatation), superior semicircular canal, posterior semicircular canal, vestibule and cochlea. Enlargement of the vestibular aqueduct also is frequently observed.