A long-term follow-up study of serial magnetic resonance images in patients with delayed encephalopathy after acute carbon monoxide poisoning.

Serial magnetic resonance (MR) images were obtained for 18 months in the follow-up of a patient with delayed encephalopathy after acute carbon monoxide (CO) poisoning. The characteristic findings on T2-weighted MR images (T2WI) were high intensity in the bilateral periventricular white matter and pallidal regions, and low intensity in the striatum. Although the neurological symptoms had improved by about 5 months after exposure, the high signal intensity in the white matter remained visible for 18 months. In addition, low signal intensity in the putamen seen on T2WI, which suggested iron deposition, was seen throughout the 18 months.