patient had good collaterals and only little damage was done by six hours we also see patients who had an hour and a half have massive damage so TPA will not help them they came in within the 3-hour window but the damage was already done so we need a different approach rather than TPA so the arbitrary time windows we don't like and what we've been doing is studies to try to show that it makes a lot more sense to look at the brain with sophisticated imaging and then try to figure out who has salvageable tissue