Neuronal damage in the interval form of CO poisoning determined by serial diffusion weighted magnetic resonance imaging plus H-1-magnetic resonance spectroscopy

In a patient with the interval form of carbon monoxide (CO) poisoning diffu sion weighted MM and proton magnetic resonance spectroscopy (H-1-MRS) were serially performed immediately after the appearance of delayed sequelae (th e 23rd day after exposure). During the period in which few clear findings w ere evident on MRI T2 weighted images, a high signal area in the cerebral w hite matter and relative decrease in the apparent diffusion coefficient (AD Cav) were already apparent on diffusion weighted images, with these finding s thought to sensitively reflect the tissue injury associated with the onse t of sequelae. The decrease in relative ADCav persisted until the 38th day after exposure. Subsequently, ADCav gradually increased, and in the cerebra l white matter showed higher values in the 118th day after exposure than im mediately after the onset of sequelae. During this period, on H-1-MRS choli ne containing compounds showed persistently high values throughout the cour se, with N-acetylaspartate depletion and the appearance of a lactate peak l ater in the course. These findings, with regional specificity in the cerebr al white matter, reflect the developmental process of the white matter lesi ons in the interval form of CO poisoning in which demyelination progresses leading to neuronal necrosis. Serial diffusion weighted imaging plus H-1-MR S measurements are useful in determining the tissue damage and long term ou tcome of delayed sequelae associated with the interval for it of CO poisoni ng.