White Matter Abnormalities on Diffusion Tensor Imaging Following Recovery from Sport-Related Concussion and Risk of Subsequent Re-injury

Abstract Purpose A recent systematic review determined that the physiological effects of concussion may persist beyond clinical recovery. Preclinical models suggest that these physiological effects are accompanied by a window of cerebral vulnerability that is associated with risk for subsequent, more severe injury. This study examined the association between persistent diffusion tensor imaging signal following clinical recovery of sport-related concussion and risk of re-injury. Methods Average mean diffusivity (MD) was obtained in a region-of-interest (ROI) in which concussed athletes showed significantly elevated MD acutely after injury (<48 hours), at an asymptomatic timepoint, 7-days post-return to play, and 6 months post-injury relative to controls. The relationship between MD in the identified ROI and risk of sustaining a subsequent concussion over a 1-year period was examined with a binary logistic regression (re-injured, yes/no). Results Eleven of 83 concussed athletes suffered a second concussion within a 1-year period. The relationship between MD at 7-days post return to play and risk of sustaining a secondary injury within 1-year showed a non-significant trend (X2(1)=4.17, p=.057, B=0.03, SE=0.017; Nagelkerke R2=0.16). Mean differences in MD between the repeat injury and non-reinjured group at 7-days post return to play produced a large effect, d=.75. MD in the a priori ROI at the other recovery time points did not predict elevated risk of re-injury. Conclusion These preliminary findings suggest that a large effect size was present in the relationship between persistent diffusion signal abnormalities and risk for subsequent re-injury. This provides support for a window of cerebral vulnerability following concussion, though further examination is needed.

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Diffusion Tensor Imaging of the Evolving Response to Mild Traumatic Brain Injury in Rats

Journal of Experimental Neuroscience ◽

10.1177/1179069519858627 ◽

2019 ◽

Vol 13 ◽

pp. 117906951985862 ◽

Cited By ~ 5

Author(s):

Wouter S Hoogenboom ◽

Todd G Rubin ◽

Kenny Ye ◽

Min-Hui Cui ◽

Kelsey C Branch ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Diffusion Tensor Imaging ◽

Brain Injury ◽

White Matter ◽

Mild Traumatic Brain Injury ◽

Diffusion Tensor ◽

Axonal Injury ◽

Mean Diffusivity ◽

Multiple Time ◽

Post Injury

Mild traumatic brain injury (mTBI), also known as concussion, is a serious public health challenge. Although most patients recover, a substantial minority suffers chronic disability. The mechanisms underlying mTBI-related detrimental effects remain poorly understood. Although animal models contribute valuable preclinical information and improve our understanding of the underlying mechanisms following mTBI, only few studies have used diffusion tensor imaging (DTI) to study the evolution of axonal injury following mTBI in rodents. It is known that DTI shows changes after human concussion and the role of delineating imaging findings in animals is therefore to facilitate understanding of related mechanisms. In this work, we used a rodent model of mTBI to investigate longitudinal indices of axonal injury. We present the results of 45 animals that received magnetic resonance imaging (MRI) at multiple time points over a 2-week period following concussive or sham injury yielding 109 serial observations. Overall, the evolution of DTI metrics following concussive or sham injury differed by group. Diffusion tensor imaging changes within the white matter were most noticeable 1 week following injury and returned to baseline values after 2 weeks. More specifically, we observed increased fractional anisotropy in combination with decreased radial diffusivity and mean diffusivity, in the absence of changes in axial diffusivity, within the white matter of the genu corpus callosum at 1 week post-injury. Our study shows that DTI can detect microstructural white matter changes in the absence of gross abnormalities as indicated by visual screening of anatomical MRI and hematoxylin and eosin (H&E)-stained sections in a clinically relevant animal model of mTBI. Whereas additional histopathologic characterization is required to better understand the neurobiological correlates of DTI measures, our findings highlight the evolving nature of the brain’s response to injury following concussion.

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Fractional anisotropy and mean diffusivity: comparison between 3.0-T and 1.5-T diffusion tensor imaging with parallel imaging using histogram and region of interest analysis

NMR in Biomedicine ◽

10.1002/nbm.1139 ◽

2007 ◽

Vol 20 (8) ◽

pp. 743-748 ◽

Cited By ~ 31

Author(s):

Yasutaka Fushimi ◽

Yukio Miki ◽

Tsutomu Okada ◽

Akira Yamamoto ◽

Nobuyuki Mori ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

Fractional Anisotropy ◽

Parallel Imaging ◽

Diffusion Tensor ◽

Mean Diffusivity ◽

Region Of Interest ◽

3.0 T

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Reduction of bias in the evaluation of fractional anisotropy and mean diffusivity in magnetic resonance diffusion tensor imaging using region-of-interest methodology

Scientific Reports ◽

10.1038/s41598-019-49311-w ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Youngseob Seo ◽

Nancy K. Rollins ◽

Zhiyue J. Wang

Keyword(s):

Diffusion Tensor Imaging ◽

Fractional Anisotropy ◽

Diffusion Tensor ◽

Signal To Noise Ratio ◽

Mean Diffusivity ◽

Region Of Interest ◽

Superior Temporal Gyrus ◽

Brain Structures ◽

Equivalence Test ◽

Mr Diffusion

Abstract Accurate quantification of fractional anisotropy (FA) and mean diffusivity (MD) in MR diffusion tensor imaging (DTI) requires adequate signal-to-noise ratio (SNR) especially in low FA areas of the brain, which necessitates clinically impractical long image acquisition times. We explored a SNR enhancement strategy using region-of-interest (ROI)-based diffusion tensor for quantification. DTI scans from a healthy male were acquired 15 times and combined into sets with different number of signal averages (NSA = 1–4, 15) at one 1.5-T Philips and three 3-T (Philips, Siemens and GE) scanners. Equivalence test was performed to determine NSA thresholds for bias-free FA and MD quantifications by comparison with reference values derived from images with NSA = 15. We examined brain areas with low FA values including caudate nucleus, globus pallidus, putamen, superior temporal gyrus, and substructures within thalamus (lateral dorsal, ventral anterior and posterior nuclei), where bias-free FA is difficult to obtain using a conventional approach. Our results showed that bias-free FA can be obtained with NSA = 2 or 3 in some cases using ROI-based analysis. ROI-based analysis allows reliable FA and MD quantifications in various brain structures previously difficult to study with clinically feasible data acquisition schemes.

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A preliminary examination of the relationship between biomechanical measures and structural changes in the brain

Trauma ◽

10.1177/1460408620916578 ◽

2020 ◽

pp. 146040862091657

Author(s):

Andrew Post ◽

Eyesha Hashim ◽

T Blaine Hoshizaki ◽

Michael D Gilchrist ◽

Michael D Cusimano

Keyword(s):

Diffusion Tensor Imaging ◽

Significant Relationship ◽

Structural Damage ◽

Diffusion Tensor ◽

Mean Diffusivity ◽

Head Impact ◽

Radial Diffusivity ◽

The Impact ◽

The Relationship ◽

The Brain

Introduction Currently, biomechanics has not been able to effectively predict when a mild traumatic brain injury may occur as a result of head impact. To improve prediction of brain trauma and the development of protective innovations, it is important to create an understanding of the relationship between the biomechanics of the head impact event and the structural damage incurred by the brain as a result of that event. The purpose of this research was to examine the relationship between diffusion tensor imaging measures and biomechanical characteristics of a head impact. Methods Diffusion tensor imaging was conducted on concussed subjects to identify regions of white matter structural differences. The injury event was reconstructed using physical and finite element methods to identify the biomechanical parameters of the impact as well as strain to the regions of the brain. Results A significant relationship was found between shear strain, rotational acceleration, and impact velocity on increases in radial diffusivity and mean diffusivity in the fornix. Linear acceleration was also found to have a weaker but significant relationship with a decrease in radial diffusivity in the cingulum hippocampus. Conclusion These results demonstrate that impacts resulting in high shear strains may affect radial diffusivity and mean diffusivity measures, and that impact mechanics likely have an important role in what regions may present differences in diffusion tensor imaging measures.

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White Matter Tract Neuroimaging and Serum Biomarker Analysis in Sports-related Concussion

Proceedings of IMPRS ◽

10.18060/25677 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Michael J. McGill ◽

Qiuting Wen ◽

Ho-Ching Yang ◽

Salman Shahid ◽

Yu-Chien Wu

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

Diffusion Tensor ◽

Serum Biomarkers ◽

Post Injury ◽

Biomarker Analysis ◽

The Relationship ◽

Insight Into ◽

Diffusion Tensor Imaging Dti ◽

Time Point

Background: Traumatic brain injury (TBI) is a leading cause of death and disability throughout the world, estimated to carry an annual global incidence of over 27 million cases. Mild TBI (mTBI), commonly known as concussion, is the mildest form of TBI and accounts for roughly 90% of all head injuries. Sports-related concussion (SRC) contributes significantly to this statistic with millions of athletes sustaining high-impact injuries in contact sports such as football, soccer, and lacrosse. By examining the white-matter microstructure, diffusion tensor imaging (DTI) has shown excellent capabilities for detecting pathophysiologic changes after SRC and monitoring symptom progression. Biomarkers including neurofilament light (NfL) and tau have been implicated in SRC and may provide insight into the duration of post-concussive symptoms. At this time, very few studies have been published evaluating the relationship between these serum biomarkers and alterations to DTI metrics. Methods: In the present study, we examined the association between serum biomarkers NfL and tau to further understand the relationship between these biomarkers and neuroimaging findings seen with diffusion tensor imaging (DTI) after exposure to a sports-related concussive event. Results: Serum tau levels decreased significantly at the 24-48h post-injury time point compared to 6h post-injury. Serum tau levels then elevated significantly at the asymptomatic time point in comparison to the 24-48h post-injury time point. The serum tau level was significantly associated with higher mean diffusivity (MD) in the white-matter tracts. Serum NfL had minimal associations with white matter diffusion metrics. Conclusion and Potential Impact: This research serves to better inform future investigations into the relationship between DTI metrics and serum biomarkers in the context of mTBI and SRC. This information may contribute to the development of a simple bedside serum analysis with potential to offer tremendous insight into the comprehensive brain health of patients who are being evaluated for SRC, thereby streamlining the therapeutic process and providing more accessible healthcare to patients in locations where advanced imaging techniques are not readily accessible.

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Diffusion tensor imaging and ventricle volume quantification in patients with chronic shunt-treated hydrocephalus: a matched case-control study

Journal of Neurosurgery ◽

10.3171/2017.6.jns162784 ◽

2018 ◽

Vol 129 (6) ◽

pp. 1611-1622 ◽

Cited By ~ 8

Author(s):

Kristy Tan ◽

Avital Meiri ◽

Wenzhu B. Mowrey ◽

Rick Abbott ◽

James T. Goodrich ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

Diffusion Tensor ◽

Mean Diffusivity ◽

White Matter Integrity ◽

Csf Shunt ◽

Periventricular White Matter ◽

Ventricular Size ◽

Long Term Effects ◽

The Relationship

OBJECTIVEThe object of this study was to use diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS) to characterize the long-term effects of hydrocephalus and shunting on white matter integrity and to investigate the relationship of ventricular size and alterations in white matter integrity with headache and quality-of-life outcome measures.METHODSPatients with shunt-treated hydrocephalus and age- and sex-matched healthy controls were recruited into the study and underwent anatomical and DTI imaging on a 3-T MRI scanner. All patients were clinically stable, had undergone CSF shunt placement before 2 years of age, and had a documented history of complaints of headaches. Outcome was scored based on the Headache Disability Inventory and the Hydrocephalus Outcome Questionnaire. Fractional anisotropy (FA) and other DTI-based measures (axial, radial, and mean diffusivity; AD, RD, and MD, respectively) were extracted in the corpus callosum and internal capsule with manual region-of-interest delineation and in other regions with TBSS. Paired t-tests, corrected with a 5% false discovery rate, were used to identify regions with significant differences between patients and controls. Within the patient group, linear regression models were used to investigate the relationship between FA or ventricular volume and outcome, as well as the effect of shunt-related covariates.RESULTSTwenty-one hydrocephalus patients and 21 matched controls completed the study, and their data were used in the final analysis. The authors found significantly lower FA for patients than for controls in 20 of the 48 regions, mostly posterior white matter structures, in periventricular as well as more distal tracts. Of these 20 regions, 17 demonstrated increased RD, while only 5 showed increased MD and 3 showed decreased AD. No areas of increased FA were observed. Higher FA in specific periventricular white matter tracts, tending toward FA in controls, was associated with increased ventricular size, as well as improved clinical outcome.CONCLUSIONSThe study shows that TBSS-based DTI is a sensitive technique for elucidating changes in white matter structures due to hydrocephalus and chronic CSF shunting and provides preliminary evidence that DTI may be a valuable tool for tailoring shunt procedures to monitor ventricular size following shunting and achieve optimal outcome, as well as for guiding the development of alternate therapies for hydrocephalus.

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Diffusion Tensor Imaging Detects Acute Pathology-Specific Changes in the P301L Tauopathy Mouse Model Following Traumatic Brain Injury

Frontiers in Neuroscience ◽

10.3389/fnins.2021.611451 ◽

2021 ◽

Vol 15 ◽

Author(s):

Neha Soni ◽

Rodrigo Medeiros ◽

Khawlah Alateeq ◽

Xuan Vinh To ◽

Fatima A. Nasrallah

Keyword(s):

Traumatic Brain Injury ◽

Diffusion Tensor Imaging ◽

Brain Injury ◽

Diffusion Tensor ◽

Mean Diffusivity ◽

Phosphorylated Tau ◽

Post Injury ◽

Ipsilateral Hemisphere ◽

Model Following ◽

The Brain

Traumatic brain injury (TBI) has been linked with tauopathy. However, imaging methods that can non-invasively detect tau-protein abnormalities following TBI need further investigation. This study aimed to investigate the potential of diffusion tensor imaging (DTI) to detect tauopathy following TBI in P301L mutant-tau-transgenic-pR5-mice. A total of 24 9-month-old pR5 mice were randomly assigned to sham and TBI groups. Controlled cortical injuries/craniotomies were performed for TBI/sham groups followed by DTI data acquisition on days 1 and 7 post-injury. DTI data were analyzed by using voxelwise analysis and track-based spatial statistics for gray matter and white matter. Further, immunohistochemistry was performed for total-tau and phosphorylated-tau, astrocytes, and microglia. To detect the association of DTI with these pathological markers, a correlation analysis was performed between DTI and histology findings. At day 1 post-TBI, DTI revealed a widespread reduction in fractional anisotropy (FA) and axial diffusivity (AxD) in the TBI group compared to shams. On day 7, further reduction in FA, AxD, and mean diffusivity and increased radial diffusivity were observed. FA was significantly increased in the amygdala and cortex. Correlation results showed that in the ipsilateral hemisphere FA reduction was associated with increased phosphorylated-tau and glial-immunoreactivity, whereas in the contralateral regions, the FA increase was associated with increased immunostaining for astrocytes. This study is the first to exploit DTI to investigate the effect of TBI in tau-transgenic mice. We show that alterations in the DTI signal were associated with glial activity following TBI and would most likely reflect changes that co-occur with/without phosphorylated-tau. In addition, FA may be a promising measure to identify discrete pathological processes such as increased astroglia activation, tau-hyperphosphorylation or both in the brain following TBI.

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Diffusion tensor imaging reveals microstructural differences between subtypes of trigeminal neuralgia

Journal of Neurosurgery ◽

10.3171/2019.4.jns19299 ◽

2020 ◽

Vol 133 (2) ◽

pp. 573-579 ◽

Cited By ~ 1

Author(s):

Matthew S. Willsey ◽

Kelly L. Collins ◽

Erin C. Conrad ◽

Heather A. Chubb ◽

Parag G. Patil

Keyword(s):

Diffusion Coefficient ◽

Diffusion Tensor Imaging ◽

Trigeminal Neuralgia ◽

Apparent Diffusion Coefficient ◽

Diffusion Tensor ◽

Statistical Significance ◽

Region Of Interest ◽

Pain Syndrome ◽

Radial Diffusivity ◽

Apparent Diffusion

OBJECTIVETrigeminal neuralgia (TN) is an uncommon idiopathic facial pain syndrome. To assist in diagnosis, treatment, and research, TN is often classified as type 1 (TN1) when pain is primarily paroxysmal and episodic or type 2 (TN2) when pain is primarily constant in character. Recently, diffusion tensor imaging (DTI) has revealed microstructural changes in the symptomatic trigeminal root and root entry zone of patients with unilateral TN. In this study, the authors explored the differences in DTI parameters between subcategories of TN, specifically TN1 and TN2, in the pontine segment of the trigeminal tract.METHODSThe authors enrolled 8 patients with unilateral TN1, 7 patients with unilateral TN2, and 23 asymptomatic controls. Patients underwent DTI with parameter measurements in a region of interest within the pontine segment of the trigeminal tract. DTI parameters were compared between groups.RESULTSIn the pontine segment, the radial diffusivity (p = 0.0049) and apparent diffusion coefficient (p = 0.023) values in TN1 patients were increased compared to the values in TN2 patients and controls. The DTI measures in TN2 were not statistically significant from those in controls. When comparing the symptomatic to asymptomatic sides in TN1 patients, radial diffusivity was increased (p = 0.025) and fractional anisotropy was decreased (p = 0.044) in the symptomatic sides. The apparent diffusion coefficient was increased, with a trend toward statistical significance (p = 0.066).CONCLUSIONSNoninvasive DTI analysis of patients with TN may lead to improved diagnosis of TN subtypes (e.g., TN1 and TN2) and improve patient selection for surgical intervention. DTI measurements may also provide insights into prognosis after intervention, as TN1 patients are known to have better surgical outcomes than TN2 patients.

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Meyer’s Loop Anatomy Demonstrated Using Diffusion Tensor MR Imaging and Fiber Tractography at 3T

Acta Medica Marisiensis ◽

10.2478/amma-2014-0045 ◽

2014 ◽

Vol 60 (5) ◽

pp. 215-222 ◽

Cited By ~ 1

Author(s):

Cristina Goga ◽

Zeynep Firat ◽

Klara Brinzaniuc ◽

Is Florian

Keyword(s):

Diffusion Tensor Imaging ◽

Diffusion Tensor ◽

Region Of Interest ◽

Fiber Tractography ◽

Brain Images ◽

3 Dimensional ◽

Software Release ◽

Magnetic Resonance Imaging Mri ◽

Meyer’S Loop

Abstract Objective: The ultimate anatomy of the Meyer’s loop continues to elude us. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) may be able to demonstrate, in vivo, the anatomy of the complex network of white matter fibers surrounding the Meyer’s loop and the optic radiations. This study aims at exploring the anatomy of the Meyer’s loop by using DTI and fiber tractography. Methods: Ten healthy subjects underwent magnetic resonance imaging (MRI) with DTI at 3 T. Using a region-of-interest (ROI) based diffusion tensor imaging and fiber tracking software (Release 2.6, Achieva, Philips), sequential ROI were placed to reconstruct visual fibers and neighboring projection fibers involved in the formation of Meyer’s loop. The 3-dimensional (3D) reconstructed fibers were visualized by superimposition on 3-planar MRI brain images to enhance their precise anatomical localization and relationship with other anatomical structures. Results: Several projection fiber including the optic radiation, occipitopontine/parietopontine fibers and posterior thalamic peduncle participated in the formation of Meyer’s loop. Two patterns of angulation of the Meyer’s loop were found. Conclusions: DTI with DTT provides a complimentary, in vivo, method to study the details of the anatomy of the Meyer’s loop.

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