Predictive value of Tc-99m-HMPAO-SPECT for neurological outcome/recovery at the acute stage of stroke

Background and Purpose: Combined perfusion and oxygen metabolism PET imagin g is highly predictive of spontaneous outcome after middle cerebral artery (MCA) stroke, independent of clinical scores, but whether the! assessment o f perfusion alone by SPECT provides similar information remains unclear. We have assessed the prognostic value of Tc-99m-HMPAO-SPECT at the acute stag e of stroke. Methods: Twenty-seven first-ever nonhemorrhagic MCA territory stroke patients were prospectively studied 4-20 h (mean: 12 h) after onset with Tc-99m-HMPAO-SPECT. None was part of a therapeutic trial or received t hrombolysis. Neurological deficits were quantified at admission and 2 month s later with Orgogozo's MCA scale. SPECT images were visually classified by 3 independent observers into one of three patterns, as follows: pattern I = marked and extensive tracer hypofixation; pattern II = moderate and/ or f ocal hypofixation with or without combined hyperfixation, and pattern III = normal or increased uptake without hypofixation. In addition to this visua l analysis, we also calculated a voxel-based 'hypoperfusion score', an inde x of severity x extent of hypofixation according to Mountz's method. Result s: There was a flood intra- and interobserver agreement. After consensus, 9 , 14 and 4 patients were classified in patterns I, II and ill, respectively . These patterns had a significant predictive value for raw outcome but nor for percentage recovery (p = 0.008 and p = 0.127, respectively). Thus, all patients in pattern III had a good outcome, while most (but not all) patie nts in pattern I had a poor or intermediate outcome; pattern II patients we re more evenly distributed among outcomes. Hypoperfusion scores were highly significantly positively correlated with both 2-month outcomes and percent age recoveries, even after controlling the predictive value of day 0 MCA sc ores by partial correlations. Comments: We found that SPECT had a significa nt added predictive value even when compared to admission neurological scor es. Although less accurate than PET, Tc-99m-HMPAO-SPECT may help to predict spontaneous individual neurological evolution, especially whenever perfusi on images are normal or show an increased tracer uptake without: associated hypofixation. Copyright (C) 2000 s. Karger AG, Basel.