Dynamic Changes in White Matter Abnormalities Correlate With Late Improvement and Deterioration Following TBI: A Diffusion Tensor Imaging Study.
OBJECTIVE
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.
University of Cambridge, Cambridge, UK vfjn2@cam.ac.uk.
Virginia F J
VF
Newcombe
University of Cambridge, Cambridge, UK.
Marta M
MM
Correia
Imperial College London, London, UK.
Christian
C
Ledig
University of Cambridge, Cambridge, UK Gerardo Hospital, Monza, Milan, Italy.
Maria G
MG
Abate
University of Cambridge, Cambridge, UK.
Joanne G
JG
Outtrim
University of Cambridge, Cambridge, UK.
Doris
D
Chatfield
University of Cambridge, Cambridge, UK University Hospital of Toulouse, Toulouse, France.
Thomas
T
Geeraerts
University of Cambridge, Cambridge, UK.
Anne E
AE
Manktelow
University of Sherbrooke, Sherbrooke, Quebec, Canada.
Eleftherios
E
Garyfallidis
University of Cambridge, Cambridge, UK.
John D
JD
Pickard
University of Cambridge, Cambridge, UK.
Barbara J
BJ
Sahakian
University of Cambridge, Cambridge, UK.
Peter J A
PJ
Hutchinson
Imperial College London, London, UK.
Daniel
D
Rueckert
University of Cambridge, Cambridge, UK.
Jonathan P
JP
Coles
University of Cambridge, Cambridge, UK.
Guy B
GB
Williams
University of Cambridge, Cambridge, UK.
David K
DK
Menon
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology*; D002908:Chronic Disease; D056324:Diffusion Tensor Imaging; D018450:Disease Progression; D005260:Female; D023261:Glasgow Outcome Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D066127:White Matter / Q000473:pathology*; D055815:Young Adult
diffusion tensor imaging; magnetic resonance imaging; traumatic brain injury