Article

There is a need to more accurately diagnose milder traumatic brain
injuries with increasing awareness of the high prevalence in both military and
civilian populations.
Magnetic resonance imaging methods may be capable of
detecting a number of the pathoanatomical and pathophysiological consequences of
focal and diffuse traumatic brain injury. Susceptibility-weighted imaging (SWI)
detects heme iron and reveals even small venous microhemorrhages occurring in
diffuse vascular injury. Diffusion tensor imaging (DTI) reveals axonal injury by
detecting alterations in water flow in and around injured axons. The overarching
hypothesis of this paper is that newer, advanced MR imaging generates sensitive
biomarkers of regional brain injury which allows for correlation with clinical
signs and symptoms. METHODS: Studies involving subjects with a history of
traumatic brain injury as well as healthy, non-trauma controls were used.
Analysis involved comparison of TBI patients' imaging results with healthy
controls as well as correlation of imaging findings with clinical measures of
injury severity. An additional animal study of Sprague-Dawley albino rats
compared imaging results with histopathological findings after the animals were
sacrificed and stained for b-APP. RESULTS: SWI revealed small foci of hemosiderin
for some patients while aggregate lesion volume on SWI correlated with clinical
injury severity indices. Similarly, DTI showed striking group differences for
fractional anisotropy over the white matter globally, while tract and voxel-based
regional results colocalized with SWI and FLAIR lesions in some cases and
correlated with clinical deficits. For the rats, correlations were seen between
imaging findings and staining of axonal injury. DISCUSSION: Animal data gave
important tissue correlations with imaging results. SWI and DTI are commercially
available sequences that can improve the diagnostic and prognostic ability of the
trauma clinician. These biomarkers of regional brain injury which are present in
imaging shortly after acute injury and persist indefinitely can inform clinicians
and researchers about not only injury severity but also which neurobehavioral
systems were injured. Analogous to stroke rehabilitation, having an understanding
of the distribution of brain injury should ultimately allow for development of
more effective rehabilitation strategies and more efficient clinical interventional trials.

Langue : ANGLAIS