Cerebral hemodynamics and "re-build-up" phenomenon on electroencephalogram in children with moyamoya disease.

"Re-build-up" phenomenon, induced by hyperventilation, is a characteristic finding on electroencephalogram (EEG) in children with moyamoya disease, and suggests close correlation with cerebral ischemic attack. Its mechanism, however, remains obscure. In this study, we examined the relationship between the cerebral hemodynamics and this phenomenon before and after vascular reconstructive surgery. Regional cerebral blood flow and its reactivity to acetazolamide were analyzed using the xenon-133 inhalation method and single photon emission computed tomography in six children with moyamoya disease. These results were compared with the EEG. Regional vasoreactivity to acetazolamide was significantly lower in "re-build-up" -positive regions than in "re-build-up" -negative regions. Postoperative studies revealed a significant improvement of reactivity in the regions where the "re-build-up" phenomenon disappeared after surgery. These results suggest that the "re-build-up" phenomenon represents a focal reduction of the cerebral perfusion reserve in moyamoya disease.