Blood flow changes in arteriovenous malformation during behavioral activation.

Striking task-dependent fluctuations were observed in the cerebral blood flow pattern of a patient with a left posterior hemispheric arteriovenous malformation (AVM). Two-dimensional measures of regional cerebral flow in the resting state, using the xenon 133 inhalation technique, revealed a region of high flow coincident with the AVM seen on the patient's arteriograms. In subsequent studies, the AVM stood out as a region of high blood flow during a relaxed state, while it approached normal levels of flow when there was attentional demand. These observations suggest that focal regulatory mechanisms exist at the AVM or else that very substantial redistributions of blood flow are taking place which the flow rate in the AVM reflects only passively. Patients considered for embolic treatment of an AVM would benefit from an assessment of behavioral influences on flow in the AVM.