Fig 2. Bland-Altman plots of the relative differences (interobserver variability, pooled data) against the mean absolute value for CBF (milliliters per 100 g per minute) (A), CBV (milliliters per 100 g) (B), and MTT (seconds) (C). The relative CBV, CBF, and MTT indicate the difference between 2 observations divided by the mean of those 2 observations, given as a percentage. The thick line represents the mean bias, and the dotted lines indicate the upper and lower limits of agreement. These upper and lower limits of agreement for the relative differences were 37% and –37% for CBV, 38% and –43% for CBF, and 21% and –16% for MTT, respectively.