Effects of peritumoural oedema on cerebral blood flow and cerebrovascular reactivity in patients with alert consciousness

The effects of peritumoural oedema on cerebral blood flow (CBF) and cerebro vascular reactivity (CVR) were studied in Is patients with alert consciousn ess. Hemispheric mean CBF was measured by performing first-pass radionuclid e angiography using technetium-99m hexamethylpropylene amine oxime. CVR was measured as the percentage change from the baseline mean CBF value after a cetazolamide administration. Patients were classified into three groups acc ording to the severity of peritumoural oedema. The mean CBF of both hemisph eres in each group was not significantly different from that of age-matched controls. CVR was preserved in patients with mild peritumoural oedema (n=6 ), but was significantly (P<0.01) reduced in patients with moderate (n=7) a nd severe peritumoural oedema (n=5). No significant correlation was found b etween the degree of midline shift and the mean CVR of both hemispheres (P= 0.09). Surgical removal of the tumour significantly (P<0.05) improved the i mpaired CVR, although the mean CBF did not change. Administration of glucoc orticoid improved the impaired CVR, without a change in the mean CBE in a p atient with a metastatic brain tumour. We conclude that CVR is impaired by the development of peritumoural oedema prior to changes in mean CBF.