Amyloid pathology and axonal injury after brain trauma #MMPMID26843562
Scott G; Ramlackhansingh AF; Edison P; Hellyer P; Cole J; Veronese M; Leech R; Greenwood RJ; Turkheimer FE; Gentleman SM; Heckemann RA; Matthews PM; Brooks DJ; Sharp DJ
Neurology 2016[Mar]; 86 (9): 821-8 PMID26843562show ga
Objective:: To image ?-amyloid (A?) plaque burden in long-term survivors of traumatic brain injury (TBI), test whether traumatic axonal injury and A? are correlated, and compare the spatial distribution of A? to Alzheimer disease (AD). Methods:: Patients 11 months to 17 years after moderate?severe TBI underwent 11C-Pittsburgh compound B (11C-PiB)-PET, structural and diffusion MRI, and neuropsychological examination. Healthy aged controls and patients with AD underwent PET and structural MRI. Binding potential (BPND) images of 11C-PiB, which index A? plaque density, were computed using an automatic reference region extraction procedure. Voxelwise and regional differences in BPND were assessed. In TBI, a measure of white matter integrity, fractional anisotropy, was estimated and correlated with 11C-PiB BPND. Results:: Twenty-eight participants (9 with TBI, 9 controls, 10 with AD) were assessed. Increased 11C-PiB BPND was found in TBI vs controls in the posterior cingulate cortex and cerebellum. Binding in the posterior cingulate cortex increased with decreasing fractional anisotropy of associated white matter tracts and increased with time since injury. Compared to AD, binding after TBI was lower in neocortical regions but increased in the cerebellum. Conclusions:: Increased A? burden was observed in TBI. The distribution overlaps with, but is distinct from, that of AD. This suggests a mechanistic link between TBI and the development of neuropathologic features of dementia, which may relate to axonal damage produced by the injury.
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Neurology 2016 ; 86 (9): 821-8
