PROGNOSTIC VALUE OF SINGLE-PHOTON EMISSION TOMOGRAPHY IN ACUTE ISCHEMIC STROKE

Single-photon emission tomography (SPET) is widely used in the investi gation of acute stroke. We investigated the relationship between SPET data and functional outcome in a large group of acute stroke patients. One hundred and eight patients underwent cerebral computed tomography (CT) and technetium-99m hexamethylpropylene amine oxime SPET after ac ute ischaemic stroke. We categorised the clinical presentation accordi ng to the Oxford classification of acute stroke. Outcome was measured 1 year after stroke using mortality and the Barthel Index for survivor s. SPET scans were interpreted without reference to the clinical data using a semi-automatic technique. Three experienced observers determin ed the presence of luxury perfusion using suitably scaled SPET images in conjunction with the CT scan. Both SPET volume and severity of defi cit were significantly negatively correlated with Barthel Index at 1 y ear (r(s)=-0.310, P <0.0001, and r(s)=-0.316, P <0.0001 respectively). In patients scanned with SPET within 16 h of stroke onset, the correl ations were more strongly negative (r(s)=-0.606, P <0.001, and r(s)=-0 .492, P <0.005 respectively). Luxury perfusion was not associated (chi (2)=0.073, df=1, P=0.79) with good functional outcome (Barthel score g reater than or equal to 60). Stepwise logistic regression identified O xford classification, total deficit volume and patient's age as signif icant predictors of functional outcome. Overall predictive accuracy wa s 72%. Predictive accuracy was better in patients who received SPET wi thin 16 h of stroke onset. SPET provides useful information about the functional outcome of acute stroke at 1 year. However, the accuracy of prediction decreases the longer SPET is delayed. Prognostication usin g SPET in combination with clinical assessment and other investigation s may also be considered.