Article

Traumatic brain injury (TBI) is not a single insult with monophasic
resolution, but a chronic disease, with dynamic processes that remain active for
years. We aimed to assess patient trajectories over the entire disease narrative,
from ictus to late outcome. METHODS: Twelve patients with moderate-to-severe TBI
underwent magnetic resonance imaging in the acute phase (within 1 week of injury)
and twice in the chronic phase of injury (median 7 and 21 months), with some
undergoing imaging at up to 2 additional time points. Longitudinal imaging
changes were assessed using structural volumetry, deterministic tractography,
voxel-based diffusion tensor analysis, and region of interest analyses (including
corpus callosum, parasagittal white matter, and thalamus). Imaging changes were
related to behavior. RESULTS: Changes in structural volumes, fractional
anisotropy, and mean diffusivity continued for months to years postictus. Changes
in diffusion tensor imaging were driven by increases in both axial and radial
diffusivity except for the earliest time point, and were associated with changes
in reaction time and performance in a visual memory and learning task (paired
associates learning). Dynamic structural changes after TBI can be detected using
diffusion tensor imaging and could explain changes in behavior. CONCLUSIONS:
These data can provide further insight into early and late pathophysiology, and
begin to provide a framework that allows magnetic resonance imaging to be used as
an imaging biomarker of therapy response. Knowledge of the temporal pattern of
changes in TBI patient populations also provides a contextual framework for
assessing imaging changes in individuals at any given time point.
CI - (c) The Author(s) 2015.

Langue : ANGLAIS