Analysis of the human brain in primary progressive multiple sclerosis with mapping of the spatial distributions using 1H MR spectroscopy and diffusion tensor imaging

Abstract

Primary progressive multiple sclerosis (ppMS; n=4) patients and controls (n=4) were examined by 1H magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in order to map choline (Cho), creatine and N-acetylaspartate (NAA), the fractional anisotropy (FA) and the apparent diffusion constant (ADC). After chemical shift imaging (point-resolved spectroscopy, repetition time/echo time 1,500 ms/135 ms) of a supraventricular volume of interest of 8x8x2 cm3 (64 voxels) MRS peak areas were matched to the results of DTI for the corresponding volume elements. Mean FA and NAA values were reduced in the ppMS patients (P<0.01, both) and the ADC increased (P<0.02). The spatial distribution of NAA showed strong correlation to ADC in both ppMS patients and controls (r =-0.74 and r= -0.70; P<0.00001, both), and weaker correlations to FA (r=0.49 and r=0.41; P<0.00001, all). FA and ADC also correlated significantly with Cho in patients and controls (P<0.00001, all). The relationship of Cho and NAA to the ADC and the FA and thus to the content of neuronal structures suggests that these metabolite signals essentially originate from axons (NAA) and the myelin sheath (Cho). This is of interest in view of previous reports in which Cho increases were associated with demyelination and the subsequent breakdown of neurons.

Loss of Glial Cells of the Hippocampus in a Rat Model of Post-traumatic Stress Disorder

“…Among these neurochemical markers, N-acetylaspartate (NAA) expressed in neurons but not in glia [14]. Decreased NAA has been found in a number of disorders including brain tumors [15], epilepsy, and multiple sclerosis [16]. In addition to NAA, 1 H MRS also detects the choline moieties (Cho), which presumably reflect cell membrane integrity.…”

“…Because Cho is highly expressed in glial cells, changes in Cho level reflect changes in the number, size, and density of glial cells [17][18][19]. Thus, by measuring levels of NAA and Cho, neuronal and glial cell integrity in the brain can be decided [15,16]. Cr as a measure of cellular energy metabolism and usually taken as the standard denominator in MRS ratio analyses [14].…”

A multicenter reproducibility study of single-voxel 1H-MRS of the medial temporal lobe

“…Extensive literature supports its usefulness for the assessment of brain tumors, epilepsy, and other neurological disorders [1,2]. In the case of dementia, the medial temporal lobe (MTL) represents the focus of earliest and most pronounced tissue degeneration and metabolic alterations and therefore turns out to be a target of particular interest.…”

Diffusion tensor MR imaging of the cervical spinal cord in patients with multiple sclerosis

“…However, the lesion load seen on conventional MRI does not correspond very well to clinical manifestations of disease extent [3]. Several studies have shown that the white matter (WM) involvement is more extensive than shown on standard MRI [4][5][6][7][8][9][10][11]. The purpose of this study was to determine whether diffusion tensor imaging (DTI) of the cervical spinal cord in MS patients will allow us to establish reliable fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of visible plaques as well as WM outside those visible lesions.…”