Atrophy in white matter fiber tracts in multiple sclerosis is not dependent on tract length or local white matter lesions

Abstract

The pathogenesis of tissue injury outside the white matter (WM) plaques of multiple sclerosis (MS) has not yet been clearly defined. To better understand the pathogenesis of this injury and the associated atrophy, we investigated volume loss over time in 20 WM fiber tracts. We defined two main aims: (1) to examine whether certain fiber tracts were more prone to atrophy, and to test the possible relation of tract atrophy to tract length and selected MS-specific variables; and (2) to investigate the possible relation of atrophy to lesion load (whole brain and in the specific tract). Local volume change was assessed between two distant time points for each MS patient studied. Fiber tracts were segmented automatically using a tractography-based atlas. Results demonstrate volume loss in all fiber tracts. The uncinate fasciculus and anterior-thalamic radiation had the greatest yearly percentage atrophy. Disease type, duration, median expanded disability status scale, total lesion load, and gender exhibited significant effects on atrophy in at least one tract. Together, these data are more consistent with a pathogenesis for the degeneration related to diffuse inflammation rather than the secondary effects of focal lesions.

Slowly eroding lesions in multiple sclerosis

“…Detailed analysis of these effects is beyond the scope of this study and would be difficult to perform reliably with available data. It is also possible that the reduction in LV observed in our data may result from global degenerative processes, rather than the other way around (29,30). …”

Development and aging of the healthy human brain uncinate fasciculus across the lifespan using diffusion tensor tractography

“…The UF has been used as a marker of tissue integrity in noninvasive magnetic resonance imaging (MRI) studies in healthy (Catani et al, 2002; Mamata et al, 2002) and diseased (Antunes et al, 2002; Aralasmak et al, 2006; Borroni et al, 2008; Kier et al, 2004; Kezele et al, 2008; Hasan et al, 2009b) populations. Other DTI reports on the UF includes using region-of-interest (Kubicki et al, 2002), voxel-based (Burns.…”

Sex hormones, brain damage and clinical course of Multiple Sclerosis

“…Maps of differences between the sexes in cortical thickness reveal a gender difference in the temporal lobes, where cortical grey matter is thicker in women than in men, and dorsal prefrontal cortex, where thickness is higher in men than in women [15]. Interestingly, grey matter regions showing gender differences in the normal brain (temporal and prefrontal cortices) are also more susceptible to gender effect in the development of brain atrophy [16]. Indeed, a regional influence of gender on atrophy of white matter tracts has been reported [16].…”

“…Interestingly, grey matter regions showing gender differences in the normal brain (temporal and prefrontal cortices) are also more susceptible to gender effect in the development of brain atrophy [16]. Indeed, a regional influence of gender on atrophy of white matter tracts has been reported [16]. Atrophy rate in white matter tracts of cingulate and the inferior longitudinal fasciculus is specifically influenced by gender, suggesting that gender differences in regional brain structure may affect the development of brain atrophy in MS.…”