FIG 3. Mean ADC values in brain regions in patients with PRES and control subjects. Percentage of patients with T2 and FLAIR signal intensity abnormalities in each brain region is shown. Both posterior and anterior circulation structures are involved. ADC values in abnormal areas in patients are elevated compared with those in control subjects (P < .04); this finding was consistent with vasogenic edema. ADC values in control subjects were lower in the cerebellum and pons (P < .001). Mean ADC values from homologous hemispheric structures are averaged together for presentation purposes.