FIGURE 5.  Correlation between K₁ estimated from 1-¹¹C-acetate and MBF estimated from ¹⁵O-water (A) and the corresponding residual plot as a function of ¹⁵O-water MBF (B). Mean residual error (MRE) was calculated as the average of the absolute difference between measured and predicted MBF values from the regression analysis in A.