FIGURE 7.  (A) Patlak plot obtained from representative subject showing linear behavior of transformed curves at times later than 30 min after injection. Slope of fitted lines represents Kcplx estimates, which closely correspond to Kcplx values derived using compartmental model. (B) Relationship between regional PSR values and Kcplx macroparameter determined using Patlak graphical analysis. Brain regions include visual cortex, brain stem, cerebellar thalamus, frontal cortex, and white matter. Line of identity is displayed as dotted line. Plot shows excellent correlation between these 2 measures of PSR ( = 0.65).