Air CT cisternography in the diagnosis of vascular loop causing vestibular nerve dysfunction.

Considerable interest has developed in otology concerning the relationship between the vascular loop and compression of the eighth nerve, producing vertigo. Several authors have described the radiographic findings relative to the anatomy of these vascular loops. Few previous articles have dealt with cases that have had surgical confirmation or repair of the defect. Our presentation concerns 27 patients who were studied by air CT cisternography of the cerebellopontine angle cistern and internal auditory canal followed by surgical repair. We postulate dampened pulsation as the reason for being able to visualize the vessels on the air study. The diversity of vessel-eighth nerve defects is illustrated. Compression of the vestibular nerve by a vascular loop should be considered one of the causes of intractable vertigo and motion intolerance and is a differential diagnosis in Meniere disease. Air CT cisternography is useful in diagnosing this condition in patients who do not respond to medical treatment.