CHRONOLOGICAL POSITRON EMISSION TOMOGRAPHIC STUDY OF SEVERE DIFFUSE BRAIN INJURY IN THE CHRONIC STAGE

Cerebral blood flow and metabolism were investigated in five patients with severe diffuse brain injury in the chronic stage, using positron emission tomography (PET). Regional cerebral blood flow, regional oxyg en extraction fraction, regional cerebral blood volume, regional cereb ral metabolic rate for oxygen, and regional cerebral metabolic rate fo r glucose were measured bilaterally in the frontal, temporal, occipita l, and parietal gray matter, as well as the white matter of the centru m semiovale. In 4 of 5 patients, a follow-up PET study was also perfor med. In three cases, below-normal regional cerebral blood flow and reg ional cerebral metabolic rate for oxygen values accompanied by above-n ormal regional oxygen extraction fraction values, as well as low metab olism, were demonstrated in the initial PET studies. In two of three c ases, clinical improvements were observed, and follow-up PET data also improved. These findings suggest that chronological PET studies may h e able to assess quantitatively clinical improvements in patients with diffuse brain injury.