The relation of focal white matter signal abnormality and focal volume loss in multiple sclerosis

Abstract

There were two aims to this study. First, to explore how the reduction in the volume of abnormal T2-signal intensity associated with white matter (WM) lesions in multiple sclerosis (MS) relates to tissue loss resulting from focal pathology inside lesions. Second, to demonstrate that this volume of abnormal T2-signal intensity underestimates the actual size of the region to which the direct effects of lesion activity extend. For these purposes, we used deformation field analysis to quantify the evolution of local atrophy associated with a chronic peri-ventricular lesion in a patient with secondary progressive MS. This subject had particular features that may not necessarily co-exist in a group of unselected patients, which enabled interesting observations to be made. We show, quantitatively, that the focal WM lesion was associated with adjacent regional WM volume loss, which was disproportionate to concurrent diffuse atrophy in the rest of the normal appearing brain tissue, and that the loss of volume associated with the lesion was partially reciprocated by local ventricular expansion. Our observations re-emphasise the complex relationship between the change in the volume of abnormal signal intensity on magnetic resonance images and the tissue volume change directly related to lesion pathology.

Reduced head and brain size for age and disproportionately smaller thalami in child-onset MS

“…26 However, as in adult-onset studies, the correlation between MRI-visible lesions and brain volumes is only moderate. We propose that the relationship between visible inflammatory (T2w) lesions and focal tissue damage (T1w lesions) and volumetric measures relates to a process whereby axonal transection in white matter lesions contributes to retrograde neuroaxonal degeneration and loss of anterograde transsynaptic pathways.…”

Early central atrophy rate predicts 5 year clinical outcome in multiple sclerosis

“…A close relationship has been demonstrated between cognitive impairment and third ventricular width or volume, possibly reflecting the clinical effect of thalamic atrophy 11 12 25–28. Furthermore, Kezele et al demonstrated a close association between focal tissue loss in periventricular lesions and local ventricular enlargement 29. Considering the central portion of the brain as the most frequent location of MS lesions, especially in the early disease stage, disruption of functionally important white matter tracts may explain the relation between ventricular enlargement and subsequent clinical disability.…”

Non-conventional MRI techniques for measuring neuroprotection, repair and plasticity in multiple sclerosis

“…Atrophy is greater in the vicinity of lesions [35 ], focal inflammatory activity in the white matter predicts atrophy, albeit weakly [37], and postmortem histopathology of segmentally demyelinated axons shows axonal swellings associated with local ATP depletion [33 ]. Taken together, these data suggest that both mechanisms are contributing to the neurodegenerative process.…”

“…Kezele and colleagues tested this hypothesis by measuring the regional atrophy around short cerebral association and projection fibres, and comparing this to the atrophy around the very long corticospinal tract [35 ]. The greatest atrophy was, in fact, observed around the short cerebral projection and association tracts, whereas the long corticospinal tract showed the least atrophy.…”