title: Correlation of diffusion and metabolic alterations in different clinical forms of multiple sclerosis.
abstract: Diffusion tensor imaging (DTI) and MR spectroscopic imaging (MRSI) provide greater sensitivity than conventional MRI to detect diffuse alterations in normal appearing white matter (NAWM) of Multiple Sclerosis (MS) patients with different clinical forms. Therefore, the goal of this study is to combine DTI and MRSI measurements to analyze the relation between diffusion and metabolic markers, T2-weighted lesion load (T2-LL) and the patients clinical status. The sensitivity and specificity of both methods were then compared in terms of MS clinical forms differentiation. MR examination was performed on 71 MS patients (27 relapsing remitting (RR), 26 secondary progressive (SP) and 18 primary progressive (PP)) and 24 control subjects. DTI and MRSI measurements were obtained from two identical regions of interest selected in left and right centrum semioval (CSO) WM. DTI metrics and metabolic contents were significantly altered in MS patients with the exception of N-acetyl-aspartate (NAA) and NAA/Choline (Cho) ratio in RR patients. Significant correlations were observed between diffusion and metabolic measures to various degrees in every MS patients group. Most DTI metrics were significantly correlated with the T2-LL while only NAA/Cr ratio was correlated in RR patients. A comparison analysis of MR methods efficiency demonstrated a better sensitivity/specificity of DTI over MRSI. Nevertheless, NAA/Cr ratio could distinguish all MS and SP patients groups from controls, while NAA/Cho ratio differentiated PP patients from controls. This study demonstrated that diffusivity changes related to microstructural alterations were correlated with metabolic changes and provided a better sensitivity to detect early changes, particularly in RR patients who are more subject to inflammatory processes. In contrast, the better specificity of metabolic ratios to detect axonal damage and demyelination may provide a better index for identification of PP patients.
authors.affiliation: CREATIS, UMR 5220 CNRS & U1044 INSERM, Université Claude Bernard-Lyon 1, Lyon, France.
authors.forename: Salem
authors.initials: S
authors.lastname: Hannoun
authors.forename: Matthieu
authors.initials: M
authors.lastname: Bagory
authors.forename: Francoise
authors.initials: F
authors.lastname: Durand-Dubief
authors.forename: Danielle
authors.initials: D
authors.lastname: Ibarrola
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Comte
authors.forename: Christian
authors.initials: C
authors.lastname: Confavreux
authors.forename: Francois
authors.initials: F
authors.lastname: Cotton
authors.forename: Dominique
authors.initials: D
authors.lastname: Sappey-Marinier
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D004058:Diffusion; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000145:classification / Q000175:diagnosis* / Q000378:metabolism; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D002794:Choline