Carbon monoxide poisoning: two cases of assessment by magnetization transfer ratios and 1H-MRS for brain damage.

We describe two patients with carbon monoxide (CO) poisoning. One developed diseased hypoxic encephalopathy, and the other recovered completely. In the patient with progressive hypoxic encephalopathy, the magnetization transfer ratios (MTRs) had already decreased during the lucid period, while the patient with complete recovery showed no reduction of MTRs during this period. 1H-MRS in the two patients revealed no definite abnormality during this lucid period. The MTR maps suggested that irreversible change had already occurred during the lucid period, and 1H-MRS was useful to determine the duration of treatment. The combination of MTRs and 1H-MRS may help to manage patients with CO poisoning.