Secondary Degeneration of White Matter After Focal Sensorimotor Cortical Ischemic Stroke in Rats

When investigating connectivity and microstructure of white matter pathways of the brain using diffusion tractography bundle segmentation, it is important to understand potential confounds and sources of variation in the process. While cross-scanner and cross-protocol effects on diffusion microstructure measures are well described (in particular fractional anisotropy and mean diffusivity), it is unknown how potential sources of variation effect bundle segmentation results, which features of the bundle are most affected, where variability occurs, nor how these sources of variation depend upon the method used to reconstruct and segment bundles. In this study, we investigate four potential sources of variation, or confounds, for bundle segmentation: variation (1) across scan repeats, (2) across scanners, (3) across acquisition protocol, and (4) across diffusion sensitization. We employ four different bundle segmentation workflows on two benchmark multi-subject cross-scanner and cross-protocol databases, and investigate reproducibility and biases in volume overlap, shape geometry features of fiber pathways, and microstructure features within the pathways. We find that the effects of acquisition protocol, in particular acquisition resolution, result in the lowest reproducibility of tractography and largest variation of features, followed by scanner-effects, and finally b-value effects which had similar reproducibility as scan-rescan variation. However, confounds varied both across pathways and across segmentation workflows, with some bundle segmentation workflows more (or less) robust to sources of variation. Despite variability, bundle dissection is consistently able to recover the same location of pathways in the deep white matter, with variation at the gray matter/ white matter interface. Next, we show that differences due to the choice of bundle segmentation workflows are larger than any other studied confound, with low-to-moderate overlap of the same intended pathway when segmented using different methods. Finally, quantifying microstructure features within a pathway, we show that tractography adds variability over-and-above that which exists due to noise, scanner effects, and acquisition effects. Overall, these confounds need to be considered when harmonizing diffusion datasets, interpreting or combining data across sites, and when attempting to understand the successes and limitations of different methodologies in the design and development of new tractography or bundle segmentation methods.

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Different white matter lesion characteristics correlate with distinct grey matter abnormalities on magnetic resonance imaging in secondary progressive multiple sclerosis

Multiple Sclerosis Journal ◽

10.1177/1352458509103176 ◽

2009 ◽

Vol 15 (6) ◽

pp. 687-694 ◽

Cited By ~ 8

Author(s):

J Furby ◽

T Hayton ◽

D Altmann ◽

R Brenner ◽

J Chataway ◽

...

Keyword(s):

Multiple Sclerosis ◽

White Matter ◽

Grey Matter ◽

Progressive Multiple Sclerosis ◽

Secondary Progressive Multiple Sclerosis ◽

Lesion Volume ◽

Secondary Degeneration ◽

Secondary Progressive ◽

Demyelinating Lesions ◽

The Relationship

Background Although MRI measures of grey matter abnormality correlate with clinical disability in multiple sclerosis, it is uncertain whether grey matter abnormality measured on MRI is entirely due to a primary grey matter process or whether it is partly related to disease in the white matter. Methods To explore potential mechanisms of grey matter damage we assessed the relationship of white matter T2 lesion volume, T1 lesion volume, and mean lesion magnetisation transfer ratio (MTR), with MRI measures of tissue atrophy and MTR in the grey matter in 117 subjects with secondary progressive multiple sclerosis. Results Grey matter fraction and mean grey matter MTR were strongly associated with lesion volumes and lesion MTR mean ( r = ±0.63–0.72). In contrast, only weak to moderate correlations existed between white matter and lesion measures. In a stepwise regression model, T1 lesion volume was the only independent lesion correlate of grey matter fraction and accounted for 52% of the variance. Lesion MTR mean and T2 lesion volume were independent correlates of mean grey matter MTR, accounting for 57% of the variance. Conclusions Axonal transection within lesions with secondary degeneration into the grey matter may explain the relationship between T1 lesions and grey matter fraction. A parallel accumulation of demyelinating lesions in white and grey matter may contribute to the association of T2 lesion volume and lesion MTR with grey matter MTR.

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Microsurgical anatomy of the central core of the brain

Journal of Neurosurgery ◽

10.3171/2017.5.jns162897 ◽

2018 ◽

Vol 129 (3) ◽

pp. 752-769 ◽

Cited By ~ 13

Author(s):

Eduardo Carvalhal Ribas ◽

Kaan Yağmurlu ◽

Evandro de Oliveira ◽

Guilherme Carvalhal Ribas ◽

Albert Rhoton

Keyword(s):

White Matter ◽

Caudate Nucleus ◽

Internal Capsule ◽

Central Core ◽

Surgical Approaches ◽

Microsurgical Anatomy ◽

Functional Importance ◽

Posterior Portion ◽

External Capsule ◽

The Brain

OBJECTIVEThe purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels.METHODSThe authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci.RESULTSThe insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the “anterior perforated substance region.” The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core.CONCLUSIONSAs a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.

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Pandora: 4-D white matter bundle population-based atlases derived from diffusion MRI fiber tractography

10.1101/2020.06.12.148999 ◽

2020 ◽

Author(s):

Colin B Hansen ◽

Qi Yang ◽

Ilwoo Lyu ◽

Francois Rheault ◽

Cailey Kerley ◽

...

Keyword(s):

White Matter ◽

Diffusion Mri ◽

State Of The Art ◽

Population Based ◽

Small Sample ◽

Fiber Tractography ◽

Statistical Inferences ◽

Small Sample Sizes ◽

The Brain ◽

Brain Atlases

AbstractBrain atlases have proven to be valuable neuroscience tools for localizing regions of interest and performing statistical inferences on populations. Although many human brain atlases exist, most do not contain information about white matter structures, often neglecting them completely or labelling all white matter as a single homogenous substrate. While few white matter atlases do exist based on diffusion MRI fiber tractography, they are often limited to descriptions of white matter as spatially separate “regions” rather than as white matter “bundles” or fascicles, which are well-known to overlap throughout the brain. Additional limitations include small sample sizes, few white matter pathways, and the use of outdated diffusion models and techniques. Here, we present a new population-based collection of white matter atlases represented in both volumetric and surface coordinates in a standard space. These atlases are based on 2443 subjects, and include 216 white matter bundles derived from 6 different state-of-the-art tractography techniques. This atlas is freely available and will be a useful resource for parcellation and segmentation.

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MRI and MRV features of a patient with Heat Stroke: a case report

10.21203/rs.2.1866/v1 ◽

2019 ◽

Author(s):

Lizhi Cao ◽

Juan Wang ◽

Yaxuan Gao ◽

Yumei Liang ◽

Jinhua Yan ◽

...

Keyword(s):

White Matter ◽

Magnetic Resonance ◽

Venous Thrombosis ◽

Cerebral Venous Thrombosis ◽

Heat Stroke ◽

Internal Capsule ◽

Subcortical White Matter ◽

Posterior Limb ◽

External Capsule ◽

The Brain

Abstract Background Heat stroke (HS) is a critical illness that can cause multiple organ dysfunction including damage to the central nervous system (CNS), which can be life-threatening in severe cases. The brain image lesions of HS patient with CNS damage has been rarely reported before and usually variable in different cases, causing confusing to doctors when encounter these patients in the clinic. Cerebral venous thrombosis (CVT) is a rare cause of stroke that mostly affects young people and children. The pathogenesis of brain damage caused by HS is complex, CVT may be involved in the pathogenesis of HS with CNS damage. In this manuscript, we report a case of HS with CVT with symmetrical lesions in the bilateral putamen,posterior limb of internal capsule,external capsule, insula lobe, and subcortical white matter inside the brain. Case presentation We introduced a 48-year-old man who suffered from HS in the hot summer. At the time of admission, he showed high body temperature, coma and shock. Later, he had laboratory evidence of rhabdomyolysis syndrome, acute kidney and liver damage, electrolyte imbalance, acid-base balance disorders, and high D-dimer levels. After several days of anti-shock treatment, his level of consciousness has improved but his vision has declined. The cerebral magnetic resonance imaging (MRI) showed symmetrical lesions of the bilateral posterior limb of internal capsule,putamen,external capsule and insula, and subcortical white matter, and cerebral magnetic resonance venography (MRV) showed the formation of deep cerebral venous thrombosis (DCVT). Therefore, the anti-coagulation treatment was given to patient. After timely clinical intervention, the symptom of the patient was gradually improved. Conclusions The case shows that HS can cause CVT. Therefore, we believe that when we need to identify the cerebral MRI findings of HS, early MRV can greatly help the diagnosis of the disease, and can effectively improve the prognosis.

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MRI and MRV features of a patient with Heat Stroke: a case report

10.21203/rs.2.1866/v2 ◽

2019 ◽

Author(s):

Lizhi Cao ◽

Juan Wang ◽

Yaxuan Gao ◽

Yumei Liang ◽

Jinhua Yan ◽

...

Keyword(s):

White Matter ◽

Magnetic Resonance ◽

Venous Thrombosis ◽

Cerebral Venous Thrombosis ◽

Heat Stroke ◽

Internal Capsule ◽

Subcortical White Matter ◽

Posterior Limb ◽

External Capsule ◽

The Brain

Abstract Background Heat stroke (HS) is a critical illness that can cause multiple organ dysfunction including damage to the central nervous system (CNS), which can be life-threatening in severe cases. The brain image lesions of HS patient with CNS damage has been rarely reported before and usually variable in different cases, causing confusing to doctors when encounter these patients in the clinic. Cerebral venous thrombosis (CVT) is a rare cause of stroke that mostly affects young people and children. The pathogenesis of brain damage caused by HS is complex, CVT may be involved in the pathogenesis of HS with CNS damage. In this manuscript, we report a case of HS with CVT with symmetrical lesions in the bilateral putamen,posterior limb of internal capsule,external capsule, insula lobe, and subcortical white matter inside the brain. Case presentation We introduced a 48-year-old man who suffered from HS in the hot summer. At the time of admission, he showed high body temperature, coma and shock. Later, he had laboratory evidence of rhabdomyolysis syndrome, acute kidney and liver damage, electrolyte imbalance, acid-base balance disorders, and high D-dimer levels. After several days of anti-shock treatment, his level of consciousness has improved but his vision has declined. The cerebral magnetic resonance imaging (MRI) showed symmetrical lesions of the bilateral posterior limb of internal capsule,putamen,external capsule and insula, and subcortical white matter, and cerebral magnetic resonance venography (MRV) showed the formation of deep cerebral venous thrombosis (DCVT). Therefore, the anti-coagulation treatment was given to patient. After timely clinical intervention, the symptom of the patient was gradually improved. Conclusions The case shows that HS can cause CVT. Therefore, we believe that when we need to identify the cerebral MRI findings of HS, early MRV can greatly help the diagnosis of the disease, and can effectively improve the prognosis.

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Structural and functional changes in the central nervous system in the course of anorexia nervosa

Current Problems of Psychiatry ◽

10.1515/cpp-2017-0025 ◽

2017 ◽

Vol 18 (4) ◽

pp. 321-330

Author(s):

Michał Hys ◽

Nikodem Skoczeń ◽

Ewelina Soroka ◽

Marcin Olajossy

Keyword(s):

Central Nervous System ◽

Eating Disorders ◽

Nervous System ◽

Anorexia Nervosa ◽

White Matter ◽

Food Intake ◽

Brain Regions ◽

Fiber Tractography ◽

Functional Changes ◽

The Brain

AbstractNew achievements within structural and functional imaging of central nervous system offer a basis for better understanding of the mechanisms underlying many mental disorders. In everyday clinical practice, we encounter many difficulties in the therapy of eating disorders. They are caused by a complex psychopathological picture, varied grounds of the problems experienced by patients, often poor motivation for active participation in the treatment process, difficulties in communication between patients and therapeutic staff, and various biological conditions of eating disorders. In this paper, the latest reports on new concepts and methods of diagnosis and treatment of anorexia nervosa have been analyzed. The selection of the analyzed publications was based on the criteria taking into account the time of publication, the size of research cohorts, as well as the experience of research teams in the field of nutritional disorders, confirmed by the number of works and their citations. The work aims to spread current information on anorexia nervosa neurobiology that would allow for determining the brain regions involved in the regulation of food intake, and consequently that may be a potential place where neurobiochemical processes responsible for eating disorders occur. In addition, using modern methods of structural imaging, the authors want to show some of the morphometric variations, particularly within white matter, occurring in patients suffering from anorexia nervosa, as well as those evaluated with magnetoencephalography of processes associated with the neuronal processing of information related to food intake. For example as regards anorexia nervosa, it was possible to localize the areas associated with eating disorders and broaden our knowledge about the changes in these areas that cause and accompany the illness. The described in this paper research studies using diffusion MRI fiber tractography showed the presence of changes in the white matter pathways of the brain, especially in the corpus callosum, which indicate a reduced content of myelin. These changes probably reflect malnutrition, and directly represent the effect of lipid deficiency. This leads to a weakening of the structure, and even cell death. In addition, there are more and more reports that show the normal volume of brain cells in patients with long-term remission of anorexia. It was also shown that in patients in remission stage there are functional changes within the amygdala in response to a task not related symptomatologically with anorexia nervosa. The appearing in the scientific literature data stating that in patients with anorexia nervosa there is a reduced density of GFAP + cells of the hippocampus and increased expression of vimentin and nestin, is also worth noting.

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Limits to anatomical accuracy of diffusion tractography using modern approaches

10.1101/392571 ◽

2018 ◽

Cited By ~ 2

Author(s):

Kurt G Schilling ◽

Vishwesh Nath ◽

Colin Hansen ◽

Prasanna Parvathaneni ◽

Justin Blaber ◽

...

Keyword(s):

White Matter ◽

Validation Studies ◽

Diffusion Mri ◽

Ex Vivo ◽

Structural Connectivity ◽

Fiber Tractography ◽

Research Groups ◽

Wide Range ◽

Modern Methods ◽

The Brain

AbstractDiffusion MRI fiber tractography is widely used to probe the structural connectivity of thebrain, with a range of applications in both clinical and basic neuroscience. Despite widespread use, tractography has well-known pitfalls that limits the anatomical accuracy of this technique. Numerous modern methods have been developed to address these shortcomings through advances in acquisition, modeling, and computation. To test whether these advances improve tractography accuracy, we organized the ISBI 2018 3D Validation of Tractography with Experimental MRI (3D-VoTEM) challenge. We made available three unique independent tractography validation datasets – a physical phantom and two ex vivo brain specimens - resulting in 176 distinct submissions from 9 research groups. By comparing results over a wide range of fiber complexities and algorithmic strategies, this challenge provides a more comprehensive assessment of tractography’s inherent limitations than has been reported previously. The central results were consistent across all sub-challenges in that, despite advances in tractography methods, the anatomical accuracy of tractography has not dramatically improved in recent years. Taken together, our results independently confirm findings from decades of tractography validation studies, demonstrate inherent limitations in reconstructing white matter pathways using diffusion MRI data alone, and highlight the need for alternative or combinatorial strategies to accurately map the fiber pathways of the brain.

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Human Brain Functional MRI and DTI Visualization With Virtual Reality

ASME 2011 World Conference on Innovative Virtual Reality ◽

10.1115/winvr2011-5565 ◽

2011 ◽

Cited By ~ 2

Author(s):

Bin Chen ◽

John Moreland ◽

Jingyu Zhang

Keyword(s):

Virtual Reality ◽

White Matter ◽

Human Brain ◽

Functional Mri ◽

Diffusion Tensor ◽

Fiber Tractography ◽

Functional Activities ◽

Brain White Matter ◽

The Brain ◽

Activation Map

Magnetic resonance diffusion tensor imaging (DTI) and functional MRI (fMRI) are two active research areas in neuroimaging. DTI is sensitive to the anisotropic diffusion of water exerted by its macromolecular environment and has been shown useful in characterizing structures of ordered tissues such as the brain white matter, myocardium, and cartilage. The diffusion tensor provides two new types of information of water diffusion: the magnitude and the spatial orientation of water diffusivity inside the tissue. This information has been used for white matter fiber tracking to review physical neuronal pathways inside the brain. Functional MRI measures brain activations using the hemodynamic response. The statistically derived activation map corresponds to human brain functional activities caused by neuronal activities. The combination of these two methods provides a new way to understand human brain from the anatomical neuronal fiber connectivity to functional activities between different brain regions. In this study, virtual reality (VR) based MR DTI and fMRI visualization with high resolution anatomical image segmentation and registration, ROI definition and neuronal white matter fiber tractography visualization and fMRI activation map integration is proposed. Rationale and methods for producing and distributing stereoscopic videos are also discussed.

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Abstract MP078: Endothelial Function and Arterial Stiffness Associated with the Extent of Brain White Matter Disease

Circulation ◽

10.1161/circ.125.suppl_10.amp078 ◽

2012 ◽

Vol 125 (suppl_10) ◽

Author(s):

Dhananjay Vaidya ◽

Paul Nyquist ◽

Brian G Kral ◽

Lisa R Yanek ◽

Taryn F Moy ◽

...

Keyword(s):

White Matter ◽

Endothelial Function ◽

Brachial Artery ◽

Mixed Model ◽

Magnetic Resonance Images ◽

White Matter Disease ◽

Lesion Volume ◽

Brain White Matter ◽

Vascular Origin ◽

The Brain

Background: Subclinical white matter disease of the brain is presumed to be of vascular origin. However associations with important facets of arterial structure and function have not been well studied. Methods: We examined 381 participants in GeneSTAR (57% female, 63% white, 37% black, age 51.6±10.5), a study of subclinical vascular disease in apparently asymptomatic individuals from families with early coronary artery disease (CAD). Volumetric measurement of white matter hyperintensities (lesion volume as a percent of brain volume, WMHV) was acquired from T3 magnetic resonance images. Ultrasound imaging of the brachial artery at rest and during hyperemia induced by 5 minutes of forearm ischemia was used to determine (1) the distensibility coefficient (DC) of the brachial artery at rest and (2) endothelial function as the percentage hyperemic flow mediated dilation (FMD). Mixed model analyses correcting for intrafamilial correlations, adjusting for age, sex, race, total and HDL-cholesterol, diabetes, hypertension, and current smoking, was used to test the association of WMHV with DC and FMD. Results: The unadjusted Spearman correlation of WMHV with FMD was -0.19 (p<0.001) and with DC was -0.11 (p=0.030). In adjusted analysis, every 10% higher FMD was associated with 0.1% lower WMHV (p=0.028) and every 10% higher DC was associated with 3.3% lower WMHV (p=0.025). When both arterial measures were included in the same regression model, the association of FMD remained significant (p=0.037), while DC remained at the borderline (p=0.052). Conclusion: Two different facets of arterial function, (a) distensibility at rest, which is a material property of vessel walls, and (b) endothelial function resulting in functional reactivity to stimuli, are independently associated with subclinical white matter disease in the brain. This study reinforces the contention that white matter disease of the brain is of vascular origin.

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