Altered white matter metabolism in delayed neurologic sequelae after carbon monoxide poisoning: A proton magnetic resonance spectroscopic study

Proton magnetic resonance spectroscopy (¹H-MRS) was recently used to examine altered metabolism in the white matter (WM) of patients experiencing carbon monoxide (CO) poisoning; however, only a small number of patients with delayed neurologic sequelae (DNS) were analyzed. We aimed to detect altered metabolism in the WM of patients with DNS using ¹H-MRS; to explore its clinical relevance in the management of patients experiencing CO poisoning. Patients experiencing acute CO poisoning underwent ¹H-MRS and cerebrospinal fluid (CSF) examination within 1 week and at 1 month after acute poisoning. Metabolites including choline-containing compounds (Cho), creatine (Cr), N-acetylaspartate (NAA), and lactate were measured from the periventricular WM. Myelin basic protein (MBP) concentrations were measured in CSF. Fifty-two patients experiencing acute CO poisoning (15 with DNS, 37 without DNS; median age, 49 years; 65% males) underwent ¹H-MRS. Within 1 week, NAA/Cr ratios, reflecting neuroaxonal viability, were lower in patients with DNS than in those without DNS (P < 0.05). At 1 month, when 9 of 15 patients (60%) developed DNS, Cho/Cr ratios were higher, and NAA/Cr and NAA/Cho ratios lower in patients with DNS (P = 0.0001, < 0.0001, and < 0.0001, respectively), indicating increased membrane metabolism and decreased neuroaxonal viability. ¹H-MRS parameter abnormalities correlated with the elevation of MBP in CSF. The presence of a lactate peak was a predictor for a poor long-term outcome. ¹H-MRS within 1 week may be useful for predicting DNS development; ¹H-MRS at 1 month may be useful for discriminating patients with DNS and predicting long-term outcomes.