1H MRSI comparison of white matter and lesions in primary progressive and relapsing-remitting MS

Abstract

Objective-To compare brain metabolite levels in patients with primary progressive (PP) and relapsing remitting (RR) MS and controls. Hypotheses: (1) creatine (Cr), a putative marker of gliosis, is elevated and N-acetylaspartate (NAA), a putative marker of axonal density and functional integrity, is reduced in PPMS lesions and normal appearing white matter (NAWM) compared to control white matter; (2) The pattern of metabolite change in PPMS is different than in RRMS.Methods-MRI and proton magnetic resonance spectroscopic imaging ( 1 H MRSI) were collected from 15 PPMS patients, 13 RRMS patients, and 20 controls.Results-Cr was increased in PPMS NAWM compared to controls (P=0.035), and compared to RRMS NAWM (P=0.038). Cr was increased in focal MRI lesions from PPMS compared to lesions from RRMS (P=0.044) and compared to control white matter (P=0.041). NAA was similarly reduced in PPMS and RRMS NAWM compared to control. NAA was similarly reduced in PPMS and RRMS lesions, compared to control white matter.Conclusions-Creatine is higher in PPMS than RRMS NAWM and focal lesions. This observation is consistent with the notion that progressive disability in PPMS reflects increased gliosis and axonal loss whereas disability in RRMS reflects the cumulative effects of acute inflammatory lesions and axonal loss.

Statistical estimation of T1 relaxation times using conventional magnetic resonance imaging

“…In both cases, the estimate of the median is higher for PPMS patients. This finding is supported by earlier work that identified indicators of increased gliosis and axonal loss in PPMS lesions relative to RRMS lesions (Suhy et al, 2000). …”

MRI lesion volume heterogeneity in primary progressive MS in relation with axonal damage and brain atrophy

“…NAA:Cr ratio in CB has been proposed as an index of axonal damage and/or dysfunction for more than a decade 16 as creatine concentration was found to be relatively constant in both lesions and NAWM of MS patients, 17 18 although others have detected increased creatine. 19 Several studies have found reduced NAA:Cr and concentration of NAA in MS lesions, NAWM, and whole brain [20][21][22] of RR and SP patients, but only a few investigators evaluated PP specifically. 12 19 23 In our study, the mean T2LL of all PP patients was 5.09 cm 3 (ranging from 0.62 to 24.77 cm 3 ), representing <2% of the CB ROI volume used to derive NAA:Cr ratios (table 1).…”

Proton Magnetic Resonance Spectroscopy in Multiple Sclerosis

“…Suhy et al72 compared metabolite levels in PPMS (n=15) and RRMS (n=13) patients with those of controls (n=20). Cr in NAWM of PPMS patients was higher compared to controls (P=0.035), and RRMS patients (P=0.038).…”