Abstract： Objective To estimate the effect of hyperbaric oxygen treatment on cerebral metabolism rate of glucose(CMRglc)in patients with delayed neuropsychological sequelae after CO poisoning(DNS).Methods Thirty cases of DNS were received 18F-FDGPET examination before hyperbaric oxygen treatment (HBOT)and after 40th HBOT respectively.At the same time 17 healthy examiner were also received 18F-FDG PET examination.Radioactive counts in bilateral frontal lobe,parietal lobe,temporal lobe,occipital lobe and ipsilateral cerebellum unit area were recorded,and the radio of radioactive counts were measured and used to evaluate PET study as semi-quantitative parameter.Results The CMRglc of DNS patient decreased in bilateral frontal lobe,parietal lobe,temporal lobe and occipital lobe before HBOT(P＜0.05).After HBOT,there were obvious improvement of CMRglc in bilateral parietal lobe,occipital lobe and left side temporal lobe(P＜0.05)and no differences in bilateral frontal lobe and right side temporal lobe.Conclusions The CMRglc decreased on the early phase of DNS.Combining hyperbaric oxygen treatment can improve CMRglc and cerebral function.