Dizziness, tinnitus, and left hearing loss. Audiogram revealed moderate rising to mild sensorineural hearing loss at 250-1500Hz, rising to normal limits 2-8kHz. The bilateral cranial nerve 7 and 8 complexes are intact. There is no evidence of mass lesions. However, there is apparent paucity of bone overlying the left superior semicircular canal. The right-sided inner ear structures, including the cochlea, vestibule, endolymphatic duct, and semicircular canals, appear unremarkable. The bilateral mastoid air cells also appear unremarkable. There is no evidence of intracranial hemorrhage, mass, or acute infarct. The brain parenchyma appears unremarkable. There is no abnormal intracranial enhancement. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The major cerebral flow voids are intact. The skull, paranasal sinuses, and scalp soft tissues are unremarkable.
Possible left superior semicircular canal dehiscence. Further evaluation via a temporal bone CT may be useful.