COMPARISON OF MEAN CEREBRAL TRANSIT-TIME AND SINGLE-PHOTON EMISSION TOMOGRAPHY FOR ESTIMATION OF STROKE OUTCOME

Mean cerebral transit time (MCTT) scanning is a possible alternative t o cerebral single-photon emission tomography (SPET) for early assessme nt of cerebral perfusion after acute ischaemic stroke. Although MCTT i s rapid, inexpensive and does not require sophisticated equipment, the relationship between MCTT and functional outcome is unknown. This stu dy aimed to compare the effectiveness of SPET and MCTT in the predicti on of functional outcome. Sixty-three patients undergoing cerebral com puted tomography (CT), technetium-99m MCTT, and technetium-99m-labelle d hexamethylpropylene amine oxime SPET soon after acute ischaemic stro ke had outcome assessed after 3 months. Cerebral CT, SPET and MCTT sca ns were interpreted without reference to the clinical data; a single i ndependent observer assessed outcome using the Barthel Index. The 3-mo nth Barthel score in survivors was significantly correlated with volum e of lesion on SPET (Spearman's r=-0.425, P<0.005) and with the ratio of mean affected hemisphere transit times to mean unaffected hemispher e transit times (Spearmen's r=-0.356, P <0.01), but not with CT lesion volume (Spearman's r = -0.175, P >0.1). Stepwise logistic regression identified volume of lesion on SPET as the only significant predictor of good functional outcome (Barthel score> 70). The overall predictive accuracy was 73%. It is concluded that MCTT, although significantly c orrelated with functional outcome, failed to predict good functional r ecovery in individual stroke survivors, Since SPET provides more detai led localisation of perfusion deficits, and since SPET lesion volume c an be used to predict functional outcome, SPET remains preferable to M CTT when perfusion imaging is required.