[Cerebral arteriovenous malformations. 2. A study of cerebral hemodynamics]

Regional cerebral blood flow (rCBF) in 16 patients with cerebral AVM was measured using 133-Xe inhalation cerebrograph, and in 3 patients rCBF was measured using stable xenon enhanced CT. Neurological status and angiographical findings were studied in the connection with rCBF measurement. RCBF in almost patients with hemorrhagic episodes was low in the frontal area (frontal depression). The larger the size of nidus is, the higher the shunt flow through nidus is, therefore, there were no significant difference of mean rCBF between the affected and non-affected hemisphere independently of the size of nidus. But in the area adjacent to AVM nidus, particularly the nidus over 20 cm3 of volume, surrounding ischemic focus was noticed. And it was thought that brain swelling due to the normal perfusion pressure break through may occur when the nidus over 20 cm3 was removed. The reduction of rCBF of the non-affected cerebral hemisphere was noticed in the cases with nearly medical seated AVM and the rCBF reduction of the non-affected or affected hemisphere was noticed in the cases with posterior fossa AVM. There was similarity between the results concerning the hemodynamic status obtained by 133-Xe inhalation cerebrograph and stable xenon enhanced CT. But 133-Xe inhalation cerebrograph was less useful for estimation of cerebral hemodynamics than the stable xenon enhanced CT, because overestimation of rCBF was noticed in 133-Xe inhalation cerebrograph.