[Cerebral angiography following hyperventilation in moyamoya disease--in reference to the "re-build up" phenomenon on EEG].

It is a well known fact that ischemic symptoms are apt to be induced after hyperventilation in child case of Moyamoya disease. We have previously noted that characteristic EEG findings are seen after hyperventilation in this disease. Among these findings, characteristic slow waves which appear after the disappearance or attenuation of ordinary build up have been labelled as "re-build up". Since this phenomenon is highly pathognomonic, we have been evaluating EEG records as an important screening test for childhood Moyamoya disease. Sequential angiograms were taken to understand the nature and pathophysiology of the "re-build up" phenomenon. We now report some interesting findings thought to be related to the particular hemodynamics and pathology of childhood Moyamoya disease. Hyperventilation angiography was performed in 17 patients with Moyamoya disease (7 children, 5 adults whose onset was in childhood and 5 adults). A control study was performed in 5 patients (one child and 4 adults) who were angiographically normal. In each patient, the presence or absence of the "re-build up" phenomenon in the EEG was determined within 1 month prior to the angiographical examination. Angiography was performed prior to 3 minutes of hyperventilation and in the period of "re-build up" under the same conditions with respect to position, site of the catheter tip, volume and the rate of injected contrast media and timing of angiography. In control cases and those cases which did not show "re-build up," angiography was performed 1 minute after termination of hyperventilation. During examination, serial arterial blood sampling was carried out for blood gas analysis. In two cases of Moyamoya disease, hyperventilation under inhalation of 8% CO2 was also performed. In patients with Moyamoya disease who showed the "re-build up" phenomenon, angiographical vascular changes such as decrease in the size of basal Moyamoya and decrease in the diameter of cortical arteries appeared together with "re-building up." These vascular changes are thought to be closely related to the "re-build up" phenomenon. In control cases and adult patients, these findings were not observed. Since these vascular changes did not occur in patients with the "re-build up" phenomenon after hyperventilation of 8% CO2, this phenomenon is thought to be initiated as a direct result of decreased arterial CO2 tension. Although during hyperventilation PaO2 increased, after hyperventilation it decreased significantly while the EEG showed "re-build up".(ABSTRACT TRUNCATED AT 400 WORDS)