Evaluation of normal appearing white matter in multiple sclerosis: comparison of diffusion magnetic resonance, magnetization transfer imaging and multivoxel magnetic resonance spectroscopy findings with expanded disability status scale.

PURPOSE

The aim of this study was to determine diffusion magnetic resonance imaging (MRI), magnetization transfer (MT) imaging and multivoxel MR spectroscopy findings in plaques, periplaque white matter and normal appearing white matter (NAWM) regions in multiple sclerosis (MS) and to correlate the findings with the expanded disability status scale (EDSS).

METHODS

A total of 30 patients with MS and 30 healthy control subjects were studied and apparent diffusion coefficient (ADC) values, MT ratio (MTR), N-acetyl-aspartate/creatine (NAA/Cr) and choline/creatine (Cho/Cr) ratios were measured in plaques, periplaques and NAWM regions and compared with the control subjects.

RESULTS

The MTR and NAA/Cr ratio were decreased more in plaques than periplaques and NAWM, in contrast ADC values and Cho/Cr ratios were highest in plaques and higher in periplaques than in NAWM. Decreased MTR and NAA/Cr in NAWM demonstrated moderate inverse correlations (r = - 0.604, p < 0.001 and r = - 0.494, p < 0.001, respectively) while Cho/Cr ratios and ADC of NAWM demonstrated weak linear correlations (r = 0.370, p = 0.004, r = 0.297, p = 0.021 respectively) with EDSS.

CONCLUSIONS

The MS, MTR and MR spectroscopy findings were found to be useful for detecting subtle abnormalities in NAWM. Although ADC values were significantly altered in plaque and periplaque regions a significance difference was not found in NAWM.