Launey Y, Fryer TD, Hong YT, et al. - Among 68 patients and 27 control candidates, researchers sought to comprehensively describe the spatiotemporal changes in cerebral physiology following traumatic brain injury (TBI). For this investigation, they used ¹⁵oxygen positron emission tomography data collected in a neurosciences critical care unit from February 1998 through July 2014 and analyzed from April 2018 through August 2019. According to this single-center cohort study, ischemia is usually seen early, detectable up to 10 days after TBI, likely without intracranial hypertension, and inconsistently identified by jugular or brain tissue oximetry. Findings revealed that there were significant between-patient and within-patient pathophysiological heterogeneity; ischemia and hyperemia usually coexist, likely indicating defects in flow-metabolism coupling. Increased cerebral blood volume can lead to intracranial hypertension but can coexist with abnormal cerebral blood flow/cerebral blood volume ratios. Such findings illustrate the need to consider the complexities of cerebrovascular pathophysiology when treating TBI patients.