question: What does it mean when you have decreased basal tracer distributionto the, bilateral parieto-occipital, bilateral patchy parietal , bilateral mesial temporal, bilateral orbitofrontal, patchycerebellar and periventricular with Cortical Metabolic index (CMi) 61.26%, within. alues (48.0-66.1)%, noted in 43 near normal patients, consistent with traumatic brain injury and mild cognitive impairment . Decreased perfusion-simulated tracer distribution, overall similar to the basal study with background corrected Cortical Perfusion index (CPi) 66.14%, within values (56.3-77.2)% noted in 43 near normal patients, and consistent with normal cerebral flow reserve index, FRi = 4.88%, vs values + (3.7-15.7)% for 43 near normal patients.