Magnetic resonance imaging (MRI) test in hemodynamic vertebro-basilar insufficiency.

We investigated the efficiency of analysis by magnetic resonance imaging (MRI) in cases of hemodynamic vertebro-basilar insufficiency (VBI). We enrolled 76 cases of hemodynamic VBI who had visited our clinic in the Department of Otolaryngology, Nara Medical University, from 1994 to 1996. The evaluation of MRI was classified according to the degree of ventricular dilatation, callosal degeneration, and lacunar infarction, and the evaluation of MR angiography (MRA) was classified according to the degree of pathological change of the blood vessels. There was a significant difference in lacunar infarction on the MRI findings between VBI cases and normal controls, and there were also significant differences in side differences in the vertebral artery between VBI cases and peripheral vertigo and normal control patients. We propose an etiology for hemodynamic VBI: a functional cerebral circulation disorder causes ischemia of the basal ganglia and leads to lacunar infarctions; furthermore, the side difference between the two vertebral arteries causes a circulation disorder in the vertebrobasilar system.