Search

The aim of this study was to determine the prognostic value of metabolic alterations in the normal-appearing white matter (NAWM) of patients presenting with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) with special regard to the prediction of conversion to definite MS. Using a 3T whole-body MR system, a multisequence conventional MRI protocol and single-voxel proton MR spectroscopy (PRESS, repetition time 2000 ms, echo times 38 ms and 140 ms) of the parietal NAWM were performed in 25 patients presenting with CIS at baseline and in 20 controls. Absolute concentrations of N-acetyl-aspartate (tNAA), myo-inositol (Ins), choline (Cho) and creatine (tCr) as well as metabolite ratios were determined. Follow-up including neurological assessment and conventional MRI was performed 3–4 and 6–7 months after the initial event. Nine patients converted to definite MS during the follow-up period. Compared to controls, those patients who converted to MS also showed significantly lower tNAA concentrations in the NAWM (−13.4%, P = 0.002) whereas nonconverters (−6.5%, P = 0.052) did not. The Ins concentration was 20.2% higher in the converter group and 1.9% higher in the nonconverter group, but these differences did not reach significance. No significant differences could be observed for tCr and Cho in either patient group. Axonal damage at baseline in patients presenting with CIS was more prominent in those who subsequently converted to definite MS in the short term follow-up, indicating that tNAA might be a sufficient prognostic marker for patients with a higher risk of conversion to early definite MS. [ABSTRACT FROM AUTHOR]

To prospectively investigate metabolic changes in the normal-appearing white matter (NAWM) of patients presenting with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) and to correlate these changes to conventional MR imaging findings in terms of MR imaging criteria. Multisequence MR imaging of the brain and 1H-MR spectroscopy of the parietal NAWM were performed in 31 patients presenting with CIS and in 20 controls using a 3. 0 T MR system. MR imaging criteria and International Panel criteria were assessed based on imaging, clinical and paraclinical results. Metabolite ratios and absolute concentrations of N-acetyl-aspartate (tNAA), myoinositol (Ins), choline (Cho), and total creatine (tCr) were determined. The metabolite concentrations were correlated with the fulfilled MR imaging criteria. In comparison to the control group, the CIS group showed significantly decreased mean tNAA concentrations (–8. 1%, p = 0. 012). Significant changes could not be detected regarding Ins, tCr and Cho. No significant correlations between absolute metabolite concentrations and MR imaging criteria were observed. Patients with and without a lesion dissemination in space showed no significant differences of their metabolite concentrations. As assessed by 1H-MRS a significant axonal damage already occurs during the first demyelinating episode in patients with CIS. Conventional MR imaging in terms of diagnostic imaging criteria does not significantly reflect NAWM disease activity in terms of metabolic alterations detected by 1H-MR spectroscopy. [ABSTRACT FROM AUTHOR]