Article

A prospective diffusion tensor imaging study in mild traumatic brain injury

The Mind Research Network, Pete & Nancy Domenici Hall, 1101 Yale Blvd. NE, Albuquerque, NM 87106, USA.
Neurology (Impact Factor: 8.3). 02/2010; 74(8):643-50. DOI: 10.1212/WNL.0b013e3181d0ccdd
Source: PubMed

ABSTRACT Only a handful of studies have investigated the nature, functional significance, and course of white matter abnormalities associated with mild traumatic brain injury (mTBI) during the semi-acute stage of injury. The present study used diffusion tensor imaging (DTI) to investigate white matter integrity and compared the accuracy of traditional anatomic scans, neuropsychological testing, and DTI for objectively classifying mTBI patients from controls.
Twenty-two patients with semi-acute mTBI (mean = 12 days postinjury), 21 matched healthy controls, and a larger sample (n = 32) of healthy controls were studied with an extensive imaging and clinical battery. A subset of participants was examined longitudinally 3-5 months after their initial visit.
mTBI patients did not differ from controls on clinical imaging scans or neuropsychological performance, although effect sizes were consistent with literature values. In contrast, mTBI patients demonstrated significantly greater fractional anisotropy as a result of reduced radial diffusivity in the corpus callosum and several left hemisphere tracts. DTI measures were more accurate than traditional clinical measures in classifying patients from controls. Longitudinal data provided preliminary evidence of partial normalization of DTI values in several white matter tracts.
Current findings of white matter abnormalities suggest that cytotoxic edema may be present during the semi-acute phase of mild traumatic brain injury (mTBI). Initial mechanical damage to axons disrupts ionic homeostasis and the ratio of intracellular and extracellular water, primarily affecting diffusion perpendicular to axons. Diffusion tensor imaging measurement may have utility for objectively classifying mTBI, and may serve as a potential biomarker of recovery.

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    • ") TBIs (N studies = 11) and, on average, were scanned approximately one year after their injury (mean = 14.4 months, SD = 18 months). Five studies examined injuries that ranged from complicated– mild (GCS = 13–15 plus visible brain lesions) to severe, three investigated mild TBIs (GCS = 13–15) (one reported in multiple papers: Borich et al., 2013; Mayer et al,. 2012; Yallampalli et al., 2010) and another examined mild to severe TBI (Wozniak et al., 2007). Four studies performed scans on children with mild TBI at 1-, 2-, or 4-weeks post-TBI and were labeled 'short-term'. The other 16 studies performed scans 3 or more months post-TBI, and included children with all levels of TBI; these were grouped into a 'medium to long-term"
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    ABSTRACT: This study meta-analyzed research examining Diffusion Tensor Imaging following pediatric non-penetrating traumatic brain injury to identify the location and extent of white matter changes. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) data from 20 studies were analyzed. FA increased and ADC decreased in most white matter tracts in the short-term (moderate-to-large effects), and FA decreased and ADC increased in the medium- to long-term (moderate-to-very-large effects). Whole brain (short-term), cerebellum and corpus callosum (medium- to long-term) FA values have diagnostic potential, but the impact of age/developmental stage and injury severity on FA/ADC, and the predictive value, is unclear.
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    • " reported increased FA , reduced ADC , and reduced radial ( perpendicular axis ) diffu - sivity in WM regions and left thalamus . Similarly , Bazarian et al . ( 2007 ) studied six mTBI patients within 72 h of injury and reported increased FA in the posterior CC and reduced ADC in the anterior limb of the internal capsule ( IC ) . Addi - tionally , Mayer et al . ( 2010 ) studied 22 mTBI patients within 12 days of injury and reported increased FA and reduced radial diffusivity in the CC and left hemisphere tracts . However , Inglese et al . ( 2005 ) found reduced FA in the splenium of CC and posterior limb of IC in 20 mTBI patients imaged up to 10 days after injury ( mean 5 4 days ) ."
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    • "Recently, diffusion tensor imaging (DTI) has shown great promise in characterizing the structural damage to white matter tracts induced by DAI. Commonly damaged regions following mild TBI include the corpus callosum (Bazarian et al. 2007; Kumar et al. 2009; Mayer et al. 2010; Warner et al. 2010), internal and external capsule (Arfanakis et al. 2002; Bazarian et al. 2007), and cingulum bundles (Mac Donald et al. 2011) (See (Aoki et al. 2012) for a meta-analysis of DTI studies in mTBI). Therefore since many previous studies have reported damage to the corpus callosum following mTBI, our goal was to specifically assess if this reported damage to structural connections between the two hemispheres would have an effect on the large-scale functional networks involved in cognitive and sensory processing. "
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