PURPOSE: To analyse MR findings of various involving sites and the relation between such findings and clinicaloutcome, the authors retrospectively reviewed MR images of acute carbon monoxide intoxication. MATERIALS AND METHODS: In 12 patients, MR images obtained from several hours to 12 days after acute carbon monoxide intoxicationwere reviewed. The images were analysed with regard to involved sites, symmetricity, signal intensity, and thepresence or absence of hemorrhage, and the relationship between MR findings and clinical outcome; the presence ofdelayed encephalopathy was then determined. RESULTS: The globus pallidus(n=9), white matter{(n=3), [centrumsemiovale(n=2), periventricular white matter(n=1)] and gyrus(n=6) [inferior temporal gyrus(n=2), cingulategyrus(n=1), precentral gyrus(n=1), hippocampal gyrus(n=1), parahippocampal gyrus(n=1)] were typically involved,and there was also involvenent of the corpus callosum(n=3), thalamus(n=2) and midbrain(n=2). All lesions of theglobus pallidus, thalamus, midbrain and temporal lobe were bilaterally symmetric. In all these cases, subtle orprominent low signal intensity was seen on spin-echo T1WI, and high signal intensity on PDWI and T2WI. Somelesions of the globus pallidus(n=1), thalamus(n=1) and midbrain(n=1) were associated with hemorrhage, whichoccurred during the early subacute stage and was seen on high/low signal intensity T1/T2WI images. Acutecerebral(n=1) and cerebellar(n=1) infarctions were also seen. Cerebral white matter involvement correlated withpoor clinical outcome, and in two cases, delayed encephalopathy developed. CONCLUSION: In these cases of acutecarbon monoxide intoxication, the globus pallidus, white matter, cortex and hippocampus were frequently involved,and there was also involvement of various sites such as the corpus callosum, thalamus and midbrain. Lesions of thetemporal lobe, thalamus and midbrain were bilaterally symmetric. The involvement of cerebral white matter and thepresence of delayed encephalopathy can influence clinical outcome.