脳梗塞再開通患者における酸素消費量の経時的変化

Cerebral Metabolic Rate of Oxygen (CMRO2) provides a direct measure of brain tissue metabolism and function, making it valuable in understanding physiological changes in infarct tissue in ischemic stroke patients. However, changes in cerebral metabolism and their significance in infarct tissue post-reperfusion remain underexplored. In this study, we examined the longitudinal changes in CMRO2 in infarct tissue in successfully reperfused ischemic stroke patients.

Fifty-one ischemic stroke patients with anterior circulation large vessel occlusion who underwent successful endovascular thrombectomy (EVT) were screened from a prospective longitudinal multicentre perspective study. MRI scans obtained at three post-EVT time points generated CBF and Oxygen Extraction Fraction (OEF) maps, from which CMRO₂ maps were calculated. Mean CMRO₂ values of manually delineated infarct ROIs and contralateral homologs were extracted and relative CMRO₂ values (ratio of infarct and contralateral CMRO₂ values) were analysed. The 3-month mRS scores were binarized into disabled (mRS > 1) and non-disabled (mRS ≤ 1), and relative CMRO₂ was compared between the groups cross-sectionally and longitudinally.

Relative CMRO₂ values decreased significantly from 24-72 hours to 3 months (p < 0.001). Relative CMRO₂ was significantly higher in the non-disabled patients than in the disabled patients at all time points, except at 24-72 hours. Longitudinal analysis in both non-disabled and disabled patients revealed a significant decrease in the relative CMRO₂ values from 24-72 hours to 3 months (p < 0.001 for both). However, after 3 months, a visual but non-significant difference in CMRO₂ trajectory was observed between the two groups.

Post successful thrombectomy, relative cerebral metabolism in the infarct is elevated in the acute stage, before stabilizing over time. Patients with better functional outcomes consistently show better cerebral metabolism than patients with poor functional outcomes.

mTICI＝ modified TICI; OEF＝ Oxygen Extraction Fraction; CMRO2 = Cerebral Metabolic Rate of Oxygen; EVT = Endovascular Thrombectomy; PRAISE = Post-Reperfusion pathophysiology in Acute Ischemic StrokE; FSL = Functional MRI of the Brain Software Library; SD = Standard Deviation; IQR = Interquartile Range; ns = not statistically significant.