COMPARISON OF CEREBRAL HEMODYNAMIC AND OXYGEN METABOLIC CHANGES DUE TO CAVERNOUS ANGIOMAS AND ARTERIOVENOUS-MALFORMATIONS OF THE BRAIN - A POSITRON EMISSION TOMOGRAPHY STUDY

The cerebral haemodynamic and metabolic changes due to cavernous angio mas in three patients and to arteriovenous malformations in four patie nts were compared by positron emission tomography, using the steady st ate technique with O-15. In the brains with a cavernous angioma no imp ortant changes in blood flow were observed. Only a decreased oxygen co nsumption was present in the cortex supplied by the arterial branches of the angioma, most probably related to neuronal deafferentation. In the four cases of arteriovenous malformation cerebral blood flow was s ignificantly increased in the territory of the feeding vessels of the angioma. In the two huge ones the oxygen extraction rate was increased in the other vascular areas remote from the supply territory of the a ngioma, indicating chronic ischaemia. The present study confirms that chronic vascular steal phenomena can occur in large arteriovenous malf ormations, while cavernous angiomas do not induce important haemodynam ic changes.