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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Traumatic brain injury (TBI) often results in traumatic axonal injury (TAI). This is difficult to identify using conventional neuroimaging methods. We review recent work that uses advanced imaging methods to identify TAI following mild (m)TBI. Susceptibility-weighted imaging (SWI) is a highly sensitive way of identifying microbleeds, which are a marker of TAI. Diffusion tensor imaging (DTI) provides a more flexible way of investigating white matter injury. Recent studies largely confirm that DTI is sensitive to white matter damage after mTBI. Distinct DTI abnormalities are observed in the acute and subacute/chronic stages. DTI measurements change dynamically after an injury, reflecting the evolving pathological processes. DTI abnormalities correlate with cognitive and neuropsychiatric impairments. Importantly, DTI can contribute to the prediction of clinical outcome and has begun to be applied to the study of sports and blast injury. DTI and SWI are important advances in MRI that allow more detailed investigation of white matter injury. SWI is a highly sensitive way of identifying microbleeds. DTI is a flexible way of quantifying white matter integrity, and provides a method of diagnosing clinically significant white matter injury when conventional imaging is normal.
    Current opinion in neurology 12/2011; 24(6):558-63. · 5.43 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: There is an urgent need to define the neurobiological and cognitive underpinnings of suicidal ideation and behavior in veterans with traumatic brain injury (TBI). Separate studies implicate frontal white matter systems in the pathophysiology of TBI, suicidality, and impulsivity. We examined the relationship between the integrity of major frontal white matter (WM) systems on measures of impulsivity and suicidality in veterans with TBI. Fifteen male veterans with TBI and 17 matched healthy controls (HC) received clinical ratings, measures of impulsivity and MRI scans on a 3T magnet. Diffusion tensor imaging (DTI) data for the genu and cingulum were analyzed using Freesurfer and FSL. Correlations were performed for fractional anisotropy (FA) (DTI) values and measures of suicidality and impulsivity for veterans with TBI. Significantly decreased in FA values in the left cingulum (P = 0.02), and left (P = 0.02) and total genu (P = 0.01) were observed in the TBI group relative to controls. Measures of impulsivity were significantly greater for the TBI group and total and right cingulum FA positively correlated with current suicidal ideation and measures of impulsivity (P <0.03). These data demonstrate a significant reduction in FA in frontal WM tracts in veterans with mild TBI that was associated with both impulsivity and suicidality. These findings may reflect a neurobiological vulnerability to suicidal risk related to white matter microstructure.
    The Journal of head trauma rehabilitation 06/2011; 26(4):276-89. · 2.39 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present state of medicolegal evaluation of persons with traumatic brain injury is discussed in this contribution. Both the ICD and German jurisdiction see a strict separation between structural and only functional brain damage that can be reliably evaluated through neurological, neuropsychological and neuroradiological means. However, there is evidence mainly from MRI investigations that there can be structural changes that presently cannot be detected in the single case, e.g. anisotropy. Furthermore, the neurological and neuropsychological differentiation of directly traumatic and psychogenic disorders can be difficult and requires expertise.
    Der Nervenarzt 11/2011; 82(12):1533-40. · 0.80 Impact Factor

Full-text (2 Sources)

Available from
Jun 2, 2014