FIG 2. Comparison of hemodynamic variables between normal subjects and patients with PRES. Graph shows ratio of values measured in the occipital lobe (posterior) to frontal lobe (anterior). Value of 1 is when posterior equals anterior. Notice significant increases in the ADC, as well as decreases in CBV and CBF, in posterior affected areas in patients with PRES. MTT shows considerable increased variability in PRES. K2 is unchanged.