High resolution MR angiography of a mouse during reperfusion. Before t-PA treatment, there is no cerebral blood flow in the right MCA. Ten minutes after starting t-PA infusion, flow on the MCA is re-established. However, signal intensity is lower than in the contralateral MCA. This reduction in cerebral blood flow is attenuated during the first 60 min after reperfusion. 24 h after MCAo and reperfusion no difference in signal intensity of the contralateral and ipsilateral MCAs is obvious (a). ADC Maps during reperfusion (b). In the first 75 min after reperfusion a slight decrease in the signal intensity of ADC is visible and 24 h after reperfusion the infarcted area is larger than at the onset. This is also detectable in the T2-weighted measurement (c).