Metabolic recovery following human traumatic brain injury based on FDG-PET: Time course and relationship to neurological disability

Objective: Utilizing [F-18]fluoroaeoxyglucose positron emission tomography (FDG-PET), we assessed the temporal pattern and the correlation of function al and metabolic recovery following human traumatic brain injury Design and Subjects: Fifty-four patients with injury severity ranging from mild to se vere were studied. Thirteen of these patients underwent both an acute and d elayed FDG-PET study Results: Analysis of the pooled global cerebral metabo lic rate of glucose (CMRglc) values revealed that the intermediate metaboli c reduction phase begins to resolve approximately one month following injur y regardless of injury severity. The correlation, in the 13 patients studie d twice, between the extent of change in neurologic disability, assessed by the Disability Rating Scale (DRS), and the change in CMRglc from the early to late period was modest (r = -0.42). Potential explanations for this rat her poor correlation are discussed. A review of the pertinent literature re garding the use of PET and related imaging modalities, including single pho ton emission tomography (SPECT) for the assessment of patients following tr aumatic brain injury is given. Conclusion: The dynamic profile of CMRglc th at changes following traumatic brain injury is seemingly stereotypic across a broad range and severity of injury types. Quantitative FDG-PET cannot be used as a surrogate technique for estimating degree of global functional r ecovery following traumatic brain injury.