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Major causes of vertigo in patients who attend Otolaryngology clinics are peripheral vestibular disorders (PVD) and vertebrobasilar insufficiency (VBI). The purpose of this study was to see whether MRA findings can distinguish VBI from PVD to evaluate the efficiency of MRA in the diagnosis of vertigo. A total of 185 vertigo patients were examined by MRA with the 3D-Phase Contrast method. Three kinds of abnormalities of vessels, that is, (a) disappearance, (b) meandering, and (c) stoppage were found in MRA imaging. Therefore, we classified the MRA patterns into four types with two subtypes: type I; normal, type II-R; right hypoform of the vertebral artery, II-L; left hypoform of the vertebral artery, III; meandering form of the vertebrobasilar artery, IV-1; stoppage form of the basilar artery, IV-2; hypoform of the bilateral vertebral and basilar arteries. Diagnosis of the MRA patterns in each patient was camed out by a radiologist and neurosurgeon with the cooperation of an otolaryngologist. In 185 vertigo patients, 139 patients were clinically diagnosed as having PVD, 41 patients as having VBI, and 5 patients as having cerebellar and brainstem infarctions. The numbers of patients in MRA patterns I, II-R, II-L, III and IV were 140, 17, 12, 8, and 8 cases, respectively. The total number of VBI patients who demonstrated type III or IV patterns in MRA was significantly higher than that of type I, II-R and II-L (P < 0.005). All of the 8 cases with cerebellar and brainstem infarction belonged to type IV. Cerebral angiography was performed in nine cases with type II-R, II-L, III or IV-1, and the number of patients in each group was 3, 3, 1 and 2 cases, respectively. All of the type II-R and II-L cases revealed hypoform of the vertebral artery. The appearance of type III was restricted to type III's view was only meandering and type IV-1 showed severe stenotic changes in the union area. These data show that MRA findings in the diagnosis of vertigo patients are very effective in distinguishing VBI and cerebellar and brainstem infarction from PVD and that some pattern of MRA may correspond to atherosclerosis of the vertebrobasilar artery. We think MRA examination of vertigo patients is useful not only to assist in the diagnosis of the etiology but also to predict the stage of atherosclerosis in each patient.