Cerebral blood flow in frontal lesions of aneurysms of the anterior communicating artery.

Abstract

The aim of this study was to investigate local and remote regional cerebral blood flow in patients with prefrontal lesions resulting from rupture (and operation) of aneurysms of the anterior communicating artery. The localization and severity of the lesions were evaluated by magnetic resonance imaging on T2 sequences. Blood flow measurements were performed in 21 patients at least 3 weeks after surgery using single-photon emission computed tomography. Flow values were calculated in 10 regions of interest in each cerebral hemisphere and compared with those of 21 control subjects matched for age. A drop in regional cerebral blood flow, predominating on the right side, was observed in the frontal areas. Flow values were not reduced in the thalamus and striatum but were significantly elevated in the posterior cortical areas and cerebellum. This latter phenomenon was significantly correlated with the severity of frontal lesions on magnetic resonance imaging. Blood flow drop in frontal areas was correlated with the cerebral lesions, which predominated in the anterior prefrontal lobe, on the side of the surgical flap; most of these prefrontal lesions were likely due to the surgical procedure and not to classic arterial spasm. Elevated perfusion in the temporo-parieto-occipital cortex and cerebellum might be due to the release of a physiological inhibition exerted by the prefrontal cortex.