[en] Apart from the well-known sudden onset of neurological deficits resulting from intracranial hemorrhage in patients with cerebral arterio-venous malformations (AVM), the pathogenesis and treatment of 1) transient and/or progressive neurological and/or neuropsychological deficits, often due to disorders of brain function removed from AVM itself, 2) focal and generalized seizures, in patients without any history of CT evidence of cerebral hemorrhage remain to be clarified. Localized or generalized episodes of ischemia resulting from cerebral steal has long been suspected but objective evidence has, so far, been lacking. To clarify this question, local cerebral blood flow (LCBF) and partition coefficients (Llambda) were measured in 10 patients with AVM and have been successfully repeated after total surgical excision in 3. Three additional patients have had excision of the AVM but CT CBF measurements were technically unsatisfactory. (Auth.)