Lesion volume in MRI. Lesion volume is shown as calculated from DWI and expressed as means ± SD. The lesion volume in the control group was larger compared to early rt-PA (rt-PA) and early combination group (com) after 2.5 hours, and larger than the early rt-PA, early G-CSF (G-CSF) and early combination group after 4 and 24 hours as shown by the single asterisks. Delayed rt-PA treatment (delayed rt-PA) resulted in larger lesion volume than the early rt-PA, early G-CSF and early combination group after 2.5 hours, and additionally larger than the control group after 4 hours. It was larger than all others after 24 hours as shown by the string sign. The late combination group (deco) showed larger infarcts than the early combination after 2.5 hours. After 4 hours, lesion volume was larger than all others with exception of delayed rt-PA. After 24 hours, there was a difference compared to the early rt-PA and early combination as indicated by the double asterisks. Levels of significance are given in table 2.