Evolution of Cerebral Infarct Volume Assessed by Diffusion-Weighted Magnetic Resonance Imaging

Abstract

SEVERAL neuroprotective agents that have shown promising results in animal stroke models have not demonstrated beneficial effects in clinical stroke trials.^1-3 Potential explanations for differing results in animals vs humans may be the more uniform infarct volumes and the possibility of initiating treatment soon after or even before stroke onset in animal models. Differences in collateral circulation between rodents and humans may be the reason why trials of neuroprotective agents in humans have not been successful.³ Another reason may be the use of different study end points. Animal studies typically use lesion volume as the primary outcome measure, whereas most clinical trials use a clinical stroke scale score. Unless the treatment dramatically affects clinical outcome, large trials are required to demonstrate efficacy using clinical scales. Most recent clinical stroke trials may not have been of sufficient size to detect a treatment effect on clinical stroke scales.²