Low choline concentrations in normal-appearing white matter of patients with multiple sclerosis and normal MR imaging brain scans

BACKGROUND AND PURPOSE: Spectroscopic studies (H-1-MR spectroscopy) of normal-appearing white matter (NAWM) in patients with multiple sclerosis (MS) with MR imaging brain lesions have already been performed, but our intention was to investigate NAWM in ME; patients who lack brain lesions to elucidate whether the same pathologic changes could be identified. MATERIALS AND METHODS: We checked 350 medical files of patients with MS who are registered in our institution. Fourteen patients (11 women and 3 men; mean age, 48.6 years; handicap score, Expanded Disability Status Scale [EDSS] 2.9; range, 1-6.5) with clinically definite MS and a normal MR imaging of the brain were included. 'H-MR spectroscopy was performed in 4 voxels (size approximately 17 X 17 X 17 mm(3)) using absolute quantification Of metabolite concentrations, Fourteen healthy control subjects (11 women and 3 men; mean age, 43.3 years) were analyzed in the same way. RESULTS: Significant differences in absolute metabolite concentrations were observed, with the patients with MS showing a lower total concentration of N-acetyl compounds (tNA), including Nacetylaspartate and N-acetyl aspartylglutannate (13.5 mmol/L versus 14.6 mmol/L; P = .002) compared with the healthy control subjects. Unexpectedly, patients with MS presented significantly lower choline-containing compounds (Cho) compared with healthy control subjects (2.2 mmol/L versus 2.4 mmol/L; P < .001). The EDSS showed a positive correlation to myo-inositol concentrations (0.14 mmol/L per EDSS; r(2) = 0.06) and a negative correlation to tNA concentrations (-0.41 mmol/L per EDSS; r(2) = 0.22). CONCLUSION: The unexpected finding of lower Cho concentrations has not been reported previously. We suggest that patients with MS who lack lesions in the brain constitute a separate entity and may have increased protective or healing abilities.