Comparison of cerebral haemodynamic 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 angiomas in three patients and to arteriovenous malformations in four patients were compared by positron emission tomography, using the steady state technique with 15O. In the brains with a cavernous angioma no important changes in blood flow were observed. Only a decreased oxygen consumption 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 significantly 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 angioma, indicating chronic ischaemia. The present study confirms that chronic vascular steal phenomena can occur in large arteriovenous malformations, while cavernous angiomas do not induce important haemodynamic changes.