Figure 4

Average abnormal DWI and MTT Volumes for all patients at each time point. The mean abnormal DWI/FLAIR volumes for the baseline, 4 hour and 24 hour time points are shown in light blue. The red bars represent the abnormal MTT volume. The mean time in hours that the images were acquired after stroke onset is shown in parenthesis on the horizontal axis. Significant differences were found with respect to time point for abnormal DWI/FLAIR volumes (ANOVA, P < 0.0001) and MTT mismatch (ANOVA, P < 0.01). No differences in these measures were found between the baseline and 4 hour scans. Significant differences were isolated between the baseline and 24 hour DWI volumes (**, P < 0.001), between the baseline abnormal DWI and 1 week abnormal FLAIR volumes (***, P < .0001), and the baseline and 24 hour MTT volumes (*, P = 0.015). The mean MTT abnormality volumes remained substantially larger than the mean DWI abnormal volumes at the baseline, 4 and 24 hour time points.