Diffusion Tensor Imaging Reliably Detects Experimental Traumatic Axonal Injury and Indicates Approximate Time of Injury

Donald, Christine L. Mac; Dikranian, Krikor; Bayly, Philip V.; Holtzman, David M.; Brody, David L.

doi:10.1523/jneurosci.3647-07.2007

Cited by 395 publications

(381 citation statements)

References 48 publications

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“…Specifically, the repeated mTBI group displayed significantly lower RD values in these regions at Day 7 as compared to Day 1 postinjury. RD is often associated with myelin pathology and edema following trauma to the brain 53, 54. Although no differences were observed between sham and injured animals following repeat ACHI, decreasing RD values in a time dependent fashion may be indicative of injury progression.…”

Section: Discussionmentioning

confidence: 96%

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Wortman

Meconi

Neale

et al. 2018

Ann Clin Transl Neurol

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ObjectiveMild traumatic brain injury (mTBI) is a serious health concern in the adolescent population. Repeated mTBI may result in more pronounced deficits, and has been associated with long‐term neurological consequences including neurodegeneration. As such, there is a critical need for the development of objective mTBI biomarkers to help guide medical management. Diffusion‐weighted imaging (DWI) is an advanced magnetic resonance imaging (MRI) technique that may detect brain abnormalities after mTBI. Diffusion tensor imaging (DTI) is the most commonly applied DWI method, and initial studies have reported DTI changes in mTBI patients. Furthermore, new DWI methods (e.g., track‐weighted imaging; TWI) are being developed that may also be sensitive to mTBIs, but remain to be comprehensively studied.MethodsThis study utilized the Awake Closed Head Injury (ACHI) model of mTBI to investigate changes in DTI and TWI following repeated mTBI in adolescent male and female rats. A total of four ACHI impacts, two/day over two consecutive days, were delivered beginning on postnatal day 25. At 1 day and 7 days postinjury, rats were euthanized and brains were collected for DWI analyses.ResultsRats given repeated mTBI displayed changes in fractional anisotropy and radial diffusivity (i.e., DTI measures), as well as track density (i.e., TWI).InterpretationThese findings are consistent with initial DTI findings in mTBI patients, suggest that TWI may complement DTI, support the utility of DWI measures as biomarkers in mTBI, and further validate the ACHI rat model of mTBI.

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Section: Discussionmentioning

confidence: 96%

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Wortman

Meconi

Neale

et al. 2018

Ann Clin Transl Neurol

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show abstract

“…Nonetheless, several recent studies using advanced neuroimaging techniques, such as diffusion tensor imaging (DTI), have elucidated changes in the white matter of mTBI patients (Bazarian et al, 2007;Huang et al, 2009;Inglese et al, 2005;Messe et al, 2010;Wilde et al, 2008). These human studies have been supported by evidence in rodent models of TBI that the signal changes seen with DTI correspond with axonal pathology (Mac Donald et al, 2007). Therefore, the current data demonstrate the potential utility of the swine mTBI model of head rotational acceleration to further these investigations by providing direct comparisons of the distribution of axonal pathology with signal changes found with advanced neuroimaging techniques, an effort that is currently underway.…”

Section: Discussionmentioning

confidence: 99%

Mild Traumatic Brain Injury and Diffuse Axonal Injury in Swine

Browne

Chen²,

Meaney³

et al. 2011

Journal of Neurotrauma

213

172

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Until recently, mild traumatic brain injury (mTBI) or ''concussion'' was generally ignored as a major health issue. However, emerging evidence suggests that this injury is by no means mild, considering it induces persisting neurocognitive dysfunction in many individuals. Although little is known about the pathophysiological aspects of mTBI, there is growing opinion that diffuse axonal injury (DAI) may play a key role. To explore this possibility, we adapted a model of head rotational acceleration in swine to produce mTBI by scaling the mechanical loading conditions based on available biomechanical data on concussion thresholds in humans. Using these input parameters, head rotational acceleration was induced in either the axial plane (transverse to the brainstem; n = 3), causing a 10-to 35-min loss of consciousness, or coronal plane (circumferential to the brainstem; n = 2), which did not produce a sustained loss of consciousness. Seven days following injury, immunohistochemical analyses of the brains revealed that both planes of head rotation induced extensive axonal pathology throughout the white matter, characterized as swollen axonal bulbs or varicosities that were immunoreactive for accumulating neurofilament protein. However, the distribution of the axonal pathology was different between planes of head rotation. In particular, more swollen axonal profiles were observed in the brainstems of animals injured in the axial plane, suggesting an anatomic substrate for prolonged loss of consciousness in mTBI. Overall, these data support DAI as an important pathological feature of mTBI, and demonstrate that surprisingly overt axonal pathology may be present, even in cases without a sustained loss of consciousness.

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“…MacDonald et al [20] used a mouse brain injury model and showed that relative anisotropy and axial diffusivity were reduced by 6 h to 4 days after trauma, corresponding to axonal injury, while 1-4 weeks after trauma, relative anisotropy remained decreased, whereas radial diffusivity increased, corresponding to demyelination, edema, and persistent axonal injury. Previous studies of ADC values in central nerve lesions such as spinal cord injury and multiple sclerosis and peripheral nerve compression such as found in carpal tunnel syndrome are controversial [15].…”

Section: Discussionmentioning

confidence: 99%

“…Recently, it has been reported that DWI is useful for the evaluation and diagnosis of lesions such as multiple sclerosis [15,16] and peripheral nerve compression disorders such as carpal tunnel syndrome [17][18][19], using diffusion values such as ADC. An increase in the mean diffusivity (ADC) values was observed in injured nerves with demyelination [15,16,19,20]. Imaging of the spinal cord is challenging because of technical limitations such as the relatively small size of the cord, susceptibility artifacts because of tissue-bone interfaces, and the motion artifacts arising from respiratory activity [21].…”

Section: Introductionmentioning

confidence: 99%

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment

et al. 2010

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Diffusion-weighted imaging (DWI) can provide valuable structural information about tissues that may be useful for clinical applications in evaluating lumbar foraminal nerve root entrapment. Our purpose was to visualize the lumbar nerve root and to analyze its morphology, and to measure its apparent diffusion coefficient (ADC) in healthy volunteers and patients with lumbar foraminal stenosis using 1.5-T magnetic resonance imaging. Fourteen patients with lumbar foraminal stenosis and 14 healthy volunteers were studied. Regions of interest were placed at the fourth and fifth lumbar root at dorsal root ganglia and distal spinal nerves (at L4 and L5) and the first sacral root and distal spinal nerve (S1) on DWI to quantify mean ADC values. The anatomic parameters of the spinal nerve roots can also be determined by neurography. In patients, mean ADC values were significantly higher in entrapped roots and distal spinal nerve than in intact ones. Neurography also showed abnormalities such as nerve indentation, swelling and running transversely in their course through the foramen. In all patients, leg pain was ameliorated after selective decompression (n = 9) or nerve block (n = 5). We demonstrated the first use of DWI and neurography of human lumbar nerves to visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis. We believe that DWI is a potential tool for diagnosis of lumbar nerve entrapment.

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Diffusion Tensor Imaging Reliably Detects Experimental Traumatic Axonal Injury and Indicates Approximate Time of Injury

Cited by 395 publications

References 48 publications

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Mild Traumatic Brain Injury and Diffuse Axonal Injury in Swine

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment

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