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Douglas H Smith - One of the best experts on this subject based on the ideXlab platform.

  • traumatic brain Injury and rationale for a neuropsychological diagnosis of Diffuse Axonal Injury
    Genes Environment and Alzheimer's Disease, 2016
    Co-Authors: Amanda R Rabinowitz, Douglas H Smith
    Abstract:

    Abstract Diffuse Axonal Injury (DAI) has been a diagnosis of exclusion in traumatic brain Injury (TBI) patients lacking positive findings on standard clinical neuroimaging. The absence of a reliable clinical diagnosis of DAI has hindered the development of effective TBI therapies. Research suggests that DAI may underlie many TBI symptoms, including cognitive dysfunction, and is probably the pathological substrate of cognitive dysfunction following mild TBI. Furthermore, evidence suggests that DAI initiates neurodegenerative processes that may contribute to the development of dementia. Cognitive findings could serve as the basis of a clinical DAI diagnosis. We review the literature on cognitive, behavioral, and neuropathological effects of TBI, and propose a paradigm shift in the neuropsychological approach to this disorder.

  • Therapy development for Diffuse Axonal Injury.
    Journal of neurotrauma, 2013
    Co-Authors: Douglas H Smith, Ramona Hicks, John T. Povlishock
    Abstract:

    Diffuse Axonal Injury (DAI) remains a prominent feature of human traumatic brain Injury (TBI) and a major player in its subsequent morbidity. The importance of this widespread Axonal damage has been confirmed by multiple approaches including routine postmortem neuropathology as well as advanced imaging, which is now capable of detecting the signatures of traumatically induced Axonal Injury across a spectrum of traumatically brain-injured persons. Despite the increased interest in DAI and its overall implications for brain-injured patients, many questions remain about this component of TBI and its potential therapeutic targeting. To address these deficiencies and to identify future directions needed to fill critical gaps in our understanding of this component of TBI, the National Institute of Neurological Disorders and Stroke hosted a workshop in May 2011. This workshop sought to determine what is known regarding the pathogenesis of DAI in animal models of Injury as well as in the human clinical setting. The workshop also addressed new tools to aid in the identification of this Axonal Injury while also identifying more rational therapeutic targets linked to DAI for continued preclinical investigation and, ultimately, clinical translation. This report encapsulates the oral and written components of this workshop addressing key features regarding the pathobiology of DAI, the biomechanics implicated in its initiating pathology, and those experimental animal modeling considerations that bear relevance to the biomechanical features of human TBI. Parallel considerations of alternate forms of DAI detection including, but not limited to, advanced neuroimaging, electrophysiological, biomarker, and neurobehavioral evaluations are included, together with recommendations for how these technologies can be better used and integrated for a more comprehensive appreciation of the pathobiology of DAI and its overall structural and functional implications. Lastly, the document closes with a thorough review of the targets linked to the pathogenesis of DAI, while also presenting a detailed report of those target-based therapies that have been used, to date, with a consideration of their overall implications for future preclinical discovery and subsequent translation to the clinic. Although all participants realize that various research gaps remained in our understanding and treatment of this complex component of TBI, this workshop refines these issues providing, for the first time, a comprehensive appreciation of what has been done and what critical needs remain unfulfilled.

  • mild traumatic brain Injury and Diffuse Axonal Injury in swine
    Journal of Neurotrauma, 2011
    Co-Authors: Kevin D Browne, David F. Meaney, Xiaohan Chen, Douglas H Smith
    Abstract:

    Abstract 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 ...

  • Diffuse Axonal Injury in head trauma
    Journal of Head Trauma Rehabilitation, 2003
    Co-Authors: Douglas H Smith, David F. Meaney, William H Shull
    Abstract:

    Abstract BACKGROUND: Diffuse Axonal Injury (DAI) is one of the most common and important pathologic features of traumatic brain Injury (TBI). The susceptibility of axons to mechanical Injury appears to be due to both their viscoelastic properties and their high organization in white matter tracts. Although axons are supple under normal conditions, they become brittle when exposed to rapid deformations associated with brain trauma. Accordingly, rapid stretch of axons can damage the Axonal cytoskeleton resulting in a loss of elasticity and impairment of axoplasmic transport. Subsequent swelling of the axon occurs in discrete bulb formations or in elongated varicosities that accumulate transported proteins. Calcium entry into damaged axons is thought to initiate further damage by the activation of proteases. Ultimately, swollen axons may become disconnected and contribute to additional neuropathologic changes in brain tissue. DAI may largely account for the clinical manifestations of brain trauma. However, DAI is extremely difficult to detect noninvasively and is poorly defined as clinical syndrome. CONCLUSIONS: Future advancements in the diagnosis and treatment of DAI will be dependent on our collective understanding of Injury biomechanics, temporal Axonal pathophysiology, and its role in patient outcome.

  • magnetization transfer imaging of Diffuse Axonal Injury following experimental brain Injury in the pig characterization by magnetization transfer ratio with histopathologic correlation
    Journal of Computer Assisted Tomography, 1996
    Co-Authors: Hirohiko Kimura, David F. Meaney, Douglas T Ross, Thomas A Gennarelli, Robert I Grossman, Joseph C Mcgowan, Robert E Lenkinski, Tracy K Mcintosh, Douglas H Smith
    Abstract:

    Purpose : Out goal was to evaluate the use of the magnetization transfer ratio (MTR) in the detection of Diffuse Axonal Injury (DAI) resulting from traumatic brain Injury in a swine model. Method : DAI was created by applying a nonimpact, coronal plane, rotational acceleration to the heads of miniature swine (n = 4). GE imaging was performed with and without off-resonance MT saturation. Histologic correlation of Axonal Injury with MRI was performed 7 days postInjury. Thirty-one subcortical white matter regions and 10 deep white matter regions were selected for the direct comparison of histologic data and MTR measurements. Results : Nineteen of 41 examined locations exhibited histologic evidence of Axonal Injury. The mean MTR in regions with Axonal damage was significantly less than in regions without Axonal damage. These changes were observed both in regions demonstrating high signal intensity on T2-weighted images (T2WI) (p < 0.0001, n = 6) and in regions with no signal intensity change on T2WI (p < 0.05, n = 13). Conclusion : These results suggest that the measurement of MTR may have the potential for evaluating Axonal damage in DAI following traumatic brain Injury even when conventional T2WI does not demonstrate the lesion.

Asta Haberg - One of the best experts on this subject based on the ideXlab platform.

  • Diffuse Axonal Injury in severe traumatic brain Injury visualized using high resolution diffusion tensor imaging
    Journal of Neurotrauma, 2007
    Co-Authors: Jian Xu, Ingeandre Rasmussen, Jim Lagopoulos, Asta Haberg
    Abstract:

    Traumatic brain Injury (TBI) is the most common cause of death and disability in young people. The functional outcome in patients with TBI cannot be explained by focal pathology alone, and Diffuse Axonal Injury (DAI) is considered a major contributor to the neurocognitive deficits experienced by this group. The aim of the present study was to investigate whether diffusion tensor imaging (DTI) offers additional information as to the extent of damage not visualized with standard magnetic resonance imaging (MRI) in patients with severe TBI. Nine chronic male TBI patients and 11 matched healthy controls were recruited. Results of the voxel-based analysis of fractional anisotropy (FA) maps and apparent diffusion coefficient (ADC) maps revealed significant differences in anisotropy in major white matter tracts, including the corpus callosum (CC), internal and external capsule, superior and inferior longitudinal fascicles, and the fornix in the TBI group. The FA and ADC measurements offered superior sensitivity ...

  • Diffuse Axonal Injury in severe traumatic brain Injury visualized using high resolution diffusion tensor imaging
    Journal of Neurotrauma, 2007
    Co-Authors: Ingeandre Rasmussen, Jim Lagopoulos, Asta Haberg
    Abstract:

    Traumatic brain Injury (TBI) is the most common cause of death and disability in young people. The functional outcome in patients with TBI cannot be explained by focal pathology alone, and Diffuse Axonal Injury (DAI) is considered a major contributor to the neurocognitive deficits experienced by this group. The aim of the present study was to investigate whether diffusion tensor imaging (DTI) offers additional information as to the extent of damage not visualized with standard magnetic resonance imaging (MRI) in patients with severe TBI. Nine chronic male TBI patients and 11 matched healthy controls were recruited. Results of the voxel-based analysis of fractional anisotropy (FA) maps and apparent diffusion coefficient (ADC) maps revealed significant differences in anisotropy in major white matter tracts, including the corpus callosum (CC), internal and external capsule, superior and inferior longitudinal fascicles, and the fornix in the TBI group. The FA and ADC measurements offered superior sensitivity compared to conventional MRI diagnosis of DAI. Region-of-interest (ROI) analyses confirmed these results in the investigated regions. The findings of this study support the hypothesis that severe TBI is accompanied by DAI. The DTI changes were more prominent on the right side that contained the focal pathology in most of the patients and accurately reflected differences in both hemispheres. In conclusion, DTI holds great promise as a diagnostic tool to identify and quantify the degree of white matter Injury in TBI patients.

Sung Ho Jang - One of the best experts on this subject based on the ideXlab platform.

  • cingulum Injury in patients with Diffuse Axonal Injury a diffusion tensor imaging study
    Neuroscience Letters, 2013
    Co-Authors: Sung Ho Jang, Seong Ho Kim, Oh Ryong Kim, Woo Mok Byun, Minsu Kim, Jeong Pyo Seo, Min Cheol Chang
    Abstract:

    Abstract Accurate assessment of the cingulum is difficult, because it is a long neural tract that extends from the orbitofrontal cortex to the medial temporal lobe. We divided the cingulum into five parts and investigated changes caused by Injury in these regions in patients with Diffuse Axonal Injury (DAI) using diffusion tensor tractography (DTT). Twenty-one patients with DAI and 21 control subjects were recruited. The cingulum was divided into; the anterior, superior (the anterior and posterior portions), posterior, and inferior regions. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), and tract number were measured in each region. FA values and tract numbers in the patient group were lower in the anterior superior cingulum than in controls (p

  • Cerebellar peduncle Injury in patients with ataxia following Diffuse Axonal Injury.
    Brain Research Bulletin, 2009
    Co-Authors: Ji Heon Hong, Oh Lyong Kim, Seong Ho Kim, Mi Young Lee, Sung Ho Jang
    Abstract:

    No diffusion tensor imaging (DTI) study has yet investigated ataxia in Diffuse Axonal Injury (DAI). In the current study, we used DTI to investigate cerebellar peduncle lesions of patients who showed severe ataxia following DAI. Six patients with severe ataxia following DAI and six age-and sex-matched control subjects were recruited. DTIs were acquired using a sensitivity-encoding head coil on a 1.5T system. Using DTI-Studio software, three cerebellar peduncles (superior cerebellar peduncle, SCP; middle cerebellar peduncle, MCP; inferior cerebellar peduncle, ICP) were evaluated. In each cerebellar peduncle, fractional anisotropy was estimated using the regions of interest method. We defined a lesion as a fractional anisotropy value two standard deviations below that of normal controls. All six patients had an average of 6.3 lesions (range 3-12). Twenty of 36 total cerebellar peduncles revealed more than one lesion (SCP: 8, ICP: 7, MCP: 5). In each of the 20 cerebellar peduncles, all the lesions displaying the lowest FA values relative to that of normal controls (11 peduncles; 55%) were located in the junction between brain stem and cerebellum and post-junctional area (nine peduncles; 45%). The junction and peri-junctional areas between the brain stem and cerebellum appear to be the most vulnerable area by DAI, with the order of incidence SCP, ICP, and MCP. Evaluation of the cerebellar peduncles using DTI can be helpful in patients with ataxia following DAI.

  • recovery of corticospinal tract with Diffuse Axonal Injury a diffusion tensor image study
    NeuroRehabilitation, 2007
    Co-Authors: Bong Soo Han, Oh Lyong Kim, Seong Ho Kim, Soo Ho Cho, Yunhee Kim, Sung Ho Jang
    Abstract:

    Objectives: The purpose of this study is to identity the recovery process of the corticospinal tract with Diffuse Axonal Injury (DAI) using diffusion tensor imaging (DTI). Design: A 47-year-old female patient and six age-matched control subjects were evaluated. The patient presented with quadri- paresis (more severe in the right extremities than the left ones) due to DAI at the onset of traumatic brain Injury. Over the 24-month period following the onset of the Injury, motor function of the four extremities slowly recovered to range which was close to normal. Two longitudinal DTIs were acquired from the patient (at 10 weeks and 24 months from onset) and from the control subjects. Fractional anisotropy (FA) and an apparent diffusion coefficient were measured using the region of interest (ROI) method. Results: On the 10-week DTI, FAs of ROIs of the brainstem in both hemispheres of the patient were significantly lower than those of the control subjects. Compared to normal controls, the patient showed significantly increased FA in both sides of the brainstem at 24 months after the onset, which occurred in parallel with the improvement in motor function. Conclusions: Recovery in this patient could be attributed to the recovery of the corticospinal tract with Diffuse Axonal Injury.

  • focal lesions of the corticospinal tract demonstrated by diffusion tensor imaging in patients with Diffuse Axonal Injury
    NeuroRehabilitation, 2006
    Co-Authors: Young Hwan Ahn, Oh Lyong Kim, Seong Ho Kim, Bong Soo Han, Sang Ho Ahn, Yoon Woo Cho, Yong Hyun Kwon, Sung Ho Jang
    Abstract:

    OBJECTIVES Diffusion tensor imaging (DTI) with fiber tractography (FT) could be useful for exploration of the state of the corticospinal tract (CST) at the subcortical white matter level. The purpose of this study was to demonstrate focal lesions of the CST in patients with Diffuse Axonal Injury (DAI), using DTI with FT. DESIGN Two patients with DAI and six normal control subjects were recruited to this study. DTI was performed using 1.5-T with a synergy-L Sensitivity Encoding (SENSE) head coil. Fractional anisotropy (FA) and apparent diffusion coefficients (ADC) were measured using a region of interest (ROI) method. FTs were obtained with FA 45 degrees as termination criteria. RESULTS On the DTI with FT, the focal lesions, which could not observed using routine brain MRI, were detected in the left brainstem of patient 1 and in the right pons and the left and right medulla of patient 2. The patients showed significantly decreased FA values in the focal lesions compared to normal controls. CONCLUSIONS DTI with FT demonstrated focal lesions at the brainstem that had not been revealed by conventional brain MRI; these focal lesions explained the weaknesses of the patients. We conclude that DTI with FT may be a useful modality for use in investigating the status of CST in patients with DAI.

  • motor recovery mechanism of Diffuse Axonal Injury a combined study of transcranial magnetic stimulation and functional mri
    Restorative Neurology and Neuroscience, 2005
    Co-Authors: Sung Ho Jang, Seong Ho Kim, Yunhee Kim, Sanghyun Cho, Sung H You, Oryong Kim, Dong Suk Yang, Su Min Son
    Abstract:

    Purpose: The purpose of this study was to investigate the motor recovery mechanism following Diffuse Axonal Injury (DAI) using transcranial magnetic stimulation (TMS) and functional MRI (fMRI). Methods: Twenty-six hands of 13 control subjects and 14 affected hands of 8 patients (two hemiparetics and six quadriparetics) were evaluated. All the patients were initially diagnosedwith DAIand were evaluated after they had reached their maximal motor recovery. fMRI was performed at 1.5 T using a hand grasp-release movement paradigm and TMS was applied with a round coil over the vertex. Results: fMRI revealed that both normal subjects and patients with DAI showed increased contralateral primary sensori-motor cortex activation during affected hand movement.The motor evoked potentials (MEPs) of the patient group was slightly delayed in latency and significantly increased in duration and turns. The relative MEP amplitude, phase, and excitatory threshold were not significantly different between the groups. Conclusions: These findings may indicate the heterogeneity of the axons in the recovery process of the corticospinal tract. It seems that the motor recovery in patients who had suffered DAI was attributable to the recovery of the corticospinal tract.

Anna E King - One of the best experts on this subject based on the ideXlab platform.

  • Diffuse Axonal Injury in brain trauma insights from alterations in neurofilaments
    Frontiers in Cellular Neuroscience, 2014
    Co-Authors: Declan G Siedler, Meng Inn Chuah, Matthew T K Kirkcaldie, J C Vickers, Anna E King
    Abstract:

    Traumatic brain Injury from penetrating or closed forces to the cranium can result in a range of forms of neural damage, which culminate in mortality or impart mild to significant neurological disability. In this regard, Diffuse Axonal Injury is a major neuronal pathophenotype of traumatic brain Injury and is associated with a complex set of cytoskeletal changes. The neurofilament triplet proteins are key structural cytoskeletal elements, which may also be important contributors to the tensile strength of axons. This has significant implications with respect to how axons may respond to traumatic brain Injury. It is not known, however, whether neurofilament compaction and the cytoskeletal changes that evolve following Axonal Injury represent a component of a protective mechanism following damage, or whether they serve to augment degeneration and progression to secondary axotomy. Here we review the structure and role of neurofilament proteins in normal neuronal function. We also discuss the processes that characterize Diffuse Axonal Injury and the resultant alterations in neurofilaments, highlighting potential clues to a possible protective or degenerative influence of specific neurofilament alterations within injured neurons. The potential utility of neurofilament assays as biomarkers for Axonal Injury is also discussed. Insights into the complex alterations in neurofilaments will contribute to future efforts in developing therapeutic strategies to prevent, ameliorate or reverse neuronal degeneration in the CNS following traumatic Injury.

  • Diffuse Axonal Injury in brain trauma insights from alterations in neurofilaments
    Frontiers in Cellular Neuroscience, 2014
    Co-Authors: Declan G Siedler, Meng Inn Chuah, Matthew T K Kirkcaldie, J C Vickers, Anna E King
    Abstract:

    Traumatic brain Injury (TBI) from penetrating or closed forces to the cranium can result in a range of forms of neural damage, which culminate in mortality or impart mild to significant neurological disability. In this regard, Diffuse Axonal Injury (DAI) is a major neuronal pathophenotype of TBI and is associated with a complex set of cytoskeletal changes. The neurofilament triplet proteins are key structural cytoskeletal elements, which may also be important contributors to the tensile strength of axons. This has significant implications with respect to how axons may respond to TBI. It is not known, however, whether neurofilament compaction and the cytoskeletal changes that evolve following Axonal Injury represent a component of a protective mechanism following damage, or whether they serve to augment degeneration and progression to secondary axotomy. Here we review the structure and role of neurofilament proteins in normal neuronal function. We also discuss the processes that characterize DAI and the resultant alterations in neurofilaments, highlighting potential clues to a possible protective or degenerative influence of specific neurofilament alterations within injured neurons. The potential utility of neurofilament assays as biomarkers for Axonal Injury is also discussed. Insights into the complex alterations in neurofilaments will contribute to future efforts in developing therapeutic strategies to prevent, ameliorate or reverse neuronal degeneration in the central nervous system (CNS) following traumatic Injury.

Robert I Grossman - One of the best experts on this subject based on the ideXlab platform.

  • Diffuse Axonal Injury in mild traumatic brain Injury a 3d multivoxel proton mr spectroscopy study
    Journal of Neurology, 2013
    Co-Authors: Ivan I Kirov, Robert I Grossman, James S Babb, Oded Gonen
    Abstract:

    Since mild traumatic brain Injury (mTBI) often leads to neurological symptoms even without clinical MRI findings, our goal was to test whether Diffuse Axonal Injury is quantifiable with multivoxel proton MR spectroscopic imaging (1H-MRSI). T1- and T2-weighted MRI images and three-dimensional 1H-MRSI (480 voxels over 360 cm3, about 30 % of the brain) were acquired at 3 T from 26 mTBI patients (mean Glasgow Coma Scale score 14.7, 18–56 years old, 3–55 days after Injury) and 13 healthy matched contemporaries as controls. The N-acetylaspartate (NAA), choline (Cho), creatine (Cr) and myo-inositol (mI) concentrations and gray-matter/white-matter (GM/WM) and cerebrospinal fluid fractions were obtained in each voxel. Global GM and WM absolute metabolic concentrations were estimated using linear regression, and patients were compared with controls using two-way analysis of variance. In patients, mean NAA, Cr, Cho and mI concentrations in GM (8.4 ± 0.7, 6.9 ± 0.6, 1.3 ± 0.2, 5.5 ± 0.6 mM) and Cr, Cho and mI in WM (4.8 ± 0.5, 1.4 ± 0.2, 4.6 ± 0.7 mM) were not different from the values in controls. The NAA concentrations in WM, however, were significantly lower in patients than in controls (7.2 ± 0.8 vs. 7.7 ± 0.6 mM, p = 0.0125). The Cho and Cr levels in WM of patients were positively correlated with time since mTBI. This 1H-MRSI approach allowed us to ascertain that early mTBI sequelae are (1) Diffuse (not merely local), (2) neuronal (not glial), and (3) in the global WM (not GM). These findings support the hypothesis that, similar to more severe head trauma, mTBI also results in Diffuse Axonal Injury, but that dysfunction rather than cell death dominates shortly after Injury.

  • Diffuse Axonal Injury in mild traumatic brain Injury a diffusion tensor imaging study
    Journal of Neurosurgery, 2005
    Co-Authors: Matilde Inglese, Oded Gonen, Sachin Makani, Glyn Johnson, Benjamin Cohen, Jonathan A Silver, Robert I Grossman
    Abstract:

    OBJECT: Diffuse Axonal Injury (DAI) is a major complication of traumatic brain Injury (TBI) that leads to functional and psychological deficits. Although DAI is frequently underdiagnosed by conventional imaging modalities, it can be demonstrated using diffusion tensor imaging. The aim of this study was to assess the presence and extent of DAI in patients with mild TBI. METHODS: Forty-six patients with mild TBI and 29 healthy volunteers underwent a magnetic resonance (MR) imaging protocol including: dual-spin echo, fluid-attenuated inversion recovery, T2-weighted gradient echo, and diffusion tensor imaging sequences. In 20 of the patients, MR imaging was performed at a mean of 4.05 days after Injury. In the remaining 26, MR imaging was performed at a mean of 5.7 years after Injury. In each case, mean diffusivity and fractional anisotropy were measured using both whole-brain histograms and regions of interest analysis. No differences in any of the histogram-derived measures were found between patients and control volunteers. Compared with controls, a significant reduction of fractional anisotropy was observed in patients' corpus callosum, internal capsule, and centrum semiovale, and there were significant increases of mean diffusivity in the corpus callosum and internal capsule. Neither histogram-derived nor regional diffusion tensor imaging metrics differed between the two groups. CONCLUSIONS: Although mean diffusivity and fractional anisotropy abnormalities in these patients with TBI were too subtle to be detected with the whole-brain histogram analysis, they are present in brain areas that are frequent sites of DAI. Because diffusion tensor imaging changes are present at both early and late time points following Injury, they may represent an early indicator and a prognostic measure of subsequent brain damage.

  • magnetization transfer imaging of Diffuse Axonal Injury following experimental brain Injury in the pig characterization by magnetization transfer ratio with histopathologic correlation
    Journal of Computer Assisted Tomography, 1996
    Co-Authors: Hirohiko Kimura, David F. Meaney, Douglas T Ross, Thomas A Gennarelli, Robert I Grossman, Joseph C Mcgowan, Robert E Lenkinski, Tracy K Mcintosh, Douglas H Smith
    Abstract:

    Purpose : Out goal was to evaluate the use of the magnetization transfer ratio (MTR) in the detection of Diffuse Axonal Injury (DAI) resulting from traumatic brain Injury in a swine model. Method : DAI was created by applying a nonimpact, coronal plane, rotational acceleration to the heads of miniature swine (n = 4). GE imaging was performed with and without off-resonance MT saturation. Histologic correlation of Axonal Injury with MRI was performed 7 days postInjury. Thirty-one subcortical white matter regions and 10 deep white matter regions were selected for the direct comparison of histologic data and MTR measurements. Results : Nineteen of 41 examined locations exhibited histologic evidence of Axonal Injury. The mean MTR in regions with Axonal damage was significantly less than in regions without Axonal damage. These changes were observed both in regions demonstrating high signal intensity on T2-weighted images (T2WI) (p < 0.0001, n = 6) and in regions with no signal intensity change on T2WI (p < 0.05, n = 13). Conclusion : These results suggest that the measurement of MTR may have the potential for evaluating Axonal damage in DAI following traumatic brain Injury even when conventional T2WI does not demonstrate the lesion.

  • prevalence of mr evidence of Diffuse Axonal Injury in patients with mild head Injury and normal head ct findings
    American Journal of Neuroradiology, 1994
    Co-Authors: R L Mittl, Thomas A Gennarelli, Robert I Grossman, J F Hiehle, Robert W Hurst, D R Kauder, G W Alburger
    Abstract:

    PURPOSE To assess the prevalence of MR evidence for Diffuse Axonal Injury at 1.5 T in patients with normal head CT findings after mild head Injury. METHODS Twenty consecutive patients with mild head Injury (Glasgow Coma Scale, 13 to 15; no subsequent deterioration, loss of consciousness RESULTS The readers agreed that abnormalities compatible with Diffuse Axonal Injury were present in the white matter of 6 (30%) of 20 patients (95% confidence interval, 12% to 54%). Both readers agreed that foci of high signal intensity were present on the T2-weighted spin-echo sequence in 3 (15%) of the 20 cases (95% confidence interval, 3% to 38%) and that foci of hypointensity compatible with hemorrhagic shear Injury were present on the T2*-weighted sequence in 4 (20%) of the 20 patients (95% confidence interval, 6% to 44%). Both types of abnormality were noted by the readers in one patient. CONCLUSIONS MR shows evidence of Diffuse Axonal Injury in some patients with normal head CT findings after mild head Injury. These lesions may represent the pathologic substrate underlying the postconcussion syndrome that occurs in many patients with moderate to severe head Injury.