scholarly journals Myelination of major white matter tracts continues beyond childhood—combining tractography and myelin water imaging

2019 ◽  
Author(s):  
Tobias W. Meissner ◽  
Erhan Genç ◽  
Burkhard Mädler ◽  
Sarah Weigelt
Keyword(s):  
White Matter ◽  
Middle Childhood ◽  
Diffusion Tensor ◽  
Late Childhood ◽  
White Matter Tracts ◽  
Water Fraction ◽  
White Matter Maturation ◽  
Myelin Water Fraction ◽  
Diffusion Tensor Imaging Dti

AbstractAxonal myelination is a key white matter maturation process as it increases conduction velocity, synchrony, and reliability. While diffusion tensor imaging (DTI) is sensitive to myelination, it is also sensitive to unrelated microstructural properties, thus hindering straightforward interpretations. Myelin water imaging (MWI) provides a more reliable and direct in vivo measure of myelination. Although early histological studies show protracted myelination from childhood to adulthood, reliable tract-specific in vivo evidence from MWI is still lacking. Here, we combine MWI and DTI tractography to investigate myelination in middle childhood, late childhood, and adulthood in 18 major white matter tracts. In the vast majority of major white matter tracts, myelin water fraction continued to increase beyond late childhood. Our study provides first in vivo evidence for protracted myelination beyond late childhood.

scholarly journals Involvement of cortico-efferent tracts in flail arm syndrome: a tract-of-interest-based DTI study

2021 ◽  
Author(s):  
Angela Rosenbohm ◽  
Kelly Del Tredici ◽  
Heiko Braak ◽  
Hans-Jürgen Huppertz ◽  
Albert C. Ludolph ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Statistical Comparison ◽  
Specific Analysis ◽  
Cerebral Pathology ◽  
Propagation Pattern ◽  
Als Patients ◽  
Lateral Sclerosis ◽  
Diffusion Tensor Imaging Dti

Abstract Background Flail arm syndrome is a restricted phenotype of motor neuron disease that is characterized by progressive, predominantly proximal weakness and atrophy of the upper limbs. Objective The study was designed to investigate specific white matter alterations in diffusion tensor imaging (DTI) data from flail arm syndrome patients using a hypothesis-guided tract-of-interest-based approach to identify in vivo microstructural changes according to a neuropathologically defined amyotrophic lateral sclerosis (ALS)-related pathology of the cortico-efferent tracts. Methods DTI-based white matter mapping was performed both by an unbiased voxel-wise statistical comparison and by a hypothesis-guided tract-wise analysis of fractional anisotropy (FA) maps according to the neuropathological ALS-propagation pattern for 43 flail arm syndrome patients vs 43 ‘classical’ ALS patients vs 40 matched controls. Results The analysis of white matter integrity demonstrated regional FA reductions for the flail arm syndrome group predominantly along the CST. In the tract-specific analysis according to the proposed sequential cerebral pathology pattern of ALS, the flail arm syndrome patients showed significant alterations of the specific tract systems that were identical to ‘classical’ ALS if compared to controls. Conclusions The DTI study including the tract-of-interest-based analysis showed a microstructural involvement pattern in the brains of flail arm syndrome patients, supporting the hypothesis that flail arm syndrome is a phenotypical variant of ALS.

Pathological basis of diffusely abnormal white matter: insights from magnetic resonance imaging and histology

2010 ◽  
Vol 17 (2) ◽  
pp. 144-150 ◽  
Author(s):  
Cornelia Laule ◽  
Irene M Vavasour ◽  
Esther Leung ◽  
David KB Li ◽  
Piotr Kozlowski ◽  
...  
Keyword(s):  
White Matter ◽  
Magnetization Transfer ◽  
Selective Reduction ◽  
Myelin Proteins ◽  
Water Fraction ◽  
Normal Appearing White Matter ◽  
Three Samples ◽  
Disability Status ◽  
Myelin Water Fraction

Background: The pathological basis of diffusely abnormal white matter (DAWM) in multiple sclerosis (MS) has not been elucidated in detail, but may be an important element in disability and clinical progression. Methods: Fifty-three subjects with MS were examined with T1, multi-echo T2 and magnetization transfer (MT). Twenty-three samples of formalin-fixed MS brain tissue were examined with multi-echo T2 and subsequently stained for myelin phospholipids using luxol fast blue, for axons using Bielschowsky, immunohistochemically for the myelin proteins myelin basic protein (MBP) and 2′,3′-cyclic nucleotide 3′ phosphohydrolase (CNP) and for astrocytes using glial fibrillary acidic protein (GFAP). Regions of interest in DAWM were compared with normal appearing white matter. Results: Fourteen of 53 subjects with MS in the in vivo study showed the presence of DAWM. Subjects with DAWM were found to have a significantly lower Expanded Disability Status Scale (EDSS) and shorter disease duration (DD) when compared with subjects without DAWM (EDSS: 1.5 versus 3.0, p = 0.031; DD: 5.4 versus 10.3 years, p = 0.045). DAWM in vivo had reduced myelin water and MT ratio, and increased T2 and water content. Histological analysis suggests DAWM, which shows a reduction of the myelin water fraction, is characterized by selective reduction of myelin phospholipids, but with a relative preservation of myelin proteins and axons. Conclusions: These findings suggest that the primary abnormality in DAWM is a reduction or perturbation of myelin phospholipids that correlates with a reduction of the myelin water fraction.

White-matter relaxation time and myelin water fraction differences in young adults with autism

2014 ◽  
Vol 45 (4) ◽  
pp. 795-805 ◽  
Author(s):  
S. C. L. Deoni ◽  
J. R. Zinkstok ◽  
E. Daly ◽  
C. Ecker ◽  
S. C. R. Williams ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Brain Connectivity ◽  
Critical Role ◽  
Relaxation Times ◽  
Imaging Study ◽  
Autism Diagnostic Observation Schedule ◽  
Cross Sectional ◽  
Water Fraction ◽  
Myelin Water Fraction

BackgroundIncreasing evidence suggests that autism is associated with abnormal white-matter (WM) anatomy and impaired brain ‘connectivity’. While myelin plays a critical role in synchronized brain communication, its aetiological role in autistic symptoms has only been indirectly addressed by WM volumetric, relaxometry and diffusion tensor imaging studies. A potentially more specific measure of myelin content, termed myelin water fraction (MWF), could provide improved sensitivity to myelin alteration in autism.MethodWe performed a cross-sectional imaging study that compared 14 individuals with autism and 14 age- and IQ-matched controls. T1 relaxation times (T1), T2 relaxation times (T2) and MWF values were compared between autistic subjects, diagnosed using the Autism Diagnostic Interview – Revised (ADI-R), with current symptoms assessed using the Autism Diagnostic Observation Schedule (ADOS) and typical healthy controls. Correlations between T1, T2 and MWF values with clinical measures [ADI-R, ADOS, and the Autism Quotient (AQ)] were also assessed.ResultsIndividuals with autism showed widespread WM T1 and MWF differences compared to typical controls. Within autistic individuals, worse current social interaction skill as measured by the ADOS was related to reduced MWF although not T1. No significant differences or correlations with symptoms were observed with respect to T2.ConclusionsAutistic individuals have significantly lower global MWF and higher T1, suggesting widespread alteration in tissue microstructure and biochemistry. Areas of difference, including thalamic projections, cerebellum and cingulum, have previously been implicated in the disorder; however, this is the first study to specifically indicate myelin alteration in these regions.

scholarly journals White matter maturation of normal human fetal brain. An in vivo diffusion tensor tractography study

2011 ◽  
Vol 1 (2) ◽  
pp. 95-108 ◽  
Author(s):  
Emilie Zanin ◽  
Jean‐Philippe Ranjeva ◽  
Sylviane Confort‐Gouny ◽  
Maxime Guye ◽  
Daniele Denis ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Fetal Brain ◽  
Diffusion Tensor Tractography ◽  
Human Fetal Brain ◽  
White Matter Maturation ◽  
Normal Human

scholarly journals Diffusion Kurtosis Imaging Fiber Tractography of Major White Matter Tracts in Neurosurgery

2021 ◽  
Vol 11 (3) ◽  
pp. 381
Author(s):  
Miriam H. A. Bopp ◽  
Julia Emde ◽  
Barbara Carl ◽  
Christopher Nimsky ◽  
Benjamin Saß
Keyword(s):  
White Matter ◽  
Corticospinal Tract ◽  
Diffusion Tensor ◽  
Clinical Applications ◽  
Diffusion Kurtosis Imaging ◽  
Fiber Tractography ◽  
White Matter Tracts ◽  
The Right ◽  
Diffusion Kurtosis ◽  
Diffusion Tensor Imaging Dti

Diffusion tensor imaging (DTI)-based fiber tractography is routinely used in clinical applications to visualize major white matter tracts, such as the corticospinal tract (CST), optic radiation (OR), and arcuate fascicle (AF). Nevertheless, DTI is limited due to its capability of resolving intra-voxel multi-fiber populations. Sophisticated models often require long acquisition times not applicable in clinical practice. Diffusion kurtosis imaging (DKI), as an extension of DTI, combines sophisticated modeling of the diffusion process with short acquisition times but has rarely been investigated in fiber tractography. In this study, DTI- and DKI-based fiber tractography of the CST, OR, and AF was investigated in healthy volunteers and glioma patients. For the CST, significantly larger tract volumes were seen in DKI-based fiber tractography. Similar results were obtained for the OR, except for the right OR in patients. In the case of the AF, results of both models were comparable with DTI-based fiber tractography showing even significantly larger tract volumes in patients. In the case of the CST and OR, DKI-based fiber tractography contributes to advanced visualization under clinical time constraints, whereas for the AF, other models should be considered.

scholarly journals Myelin development in visual scene-network tracts beyond late childhood: A multimethod neuroimaging study

2019 ◽  
Author(s):  
Tobias W Meissner ◽  
Erhan Genç ◽  
Burkhard Mädler ◽  
Sarah Weigelt
Keyword(s):  
White Matter ◽  
Middle Childhood ◽  
Retrosplenial Cortex ◽  
Visual Scene ◽  
Late Childhood ◽  
Structural Development ◽  
Gold Standard Method ◽  
Network Function ◽  
Functional Development

The visual scene-network - comprising the parahippocampal place area (PPA), retrosplenial cortex (RSC), and occipital place area (OPA) - shows a prolonged functional development. Structural development of white matter that underlies the scene-network has not been investigated despite its potential influence on scene-network function. The key factor for white matter maturation is myelination. However, research on myelination using the gold standard method of post-mortem histology is scarce. In vivo alternatives diffusion-weighed imaging (DWI) and myelin water imaging (MWI) so far report broad-scale findings that prohibit inferences concerning the scene-network. Here, we combine MWI, DWI tractography, and fMRI to investigate myelination in scene-network tracts in middle childhood, late childhood, and adulthood. We report increasing myelin from middle childhood to adulthood in right PPA-OPA, and trends towards increases in the left and right RSC-OPA tracts. Investigating tracts to regions highly connected with the scene-network, such as early visual cortex and the hippocampus did not yield any significant age group differences. Our findings indicate that structural development coincides with functional development in the scene-network, possibly enabling structure-function interactions.

Diffusion Tensor (DT)-MRI of the Brain. Review of Clinical Pediatric Applications

2005 ◽  
Vol 18 (3) ◽  
pp. 266-288 ◽  
Author(s):  
B. Bernardi ◽  
G. Price ◽  
E. Thomas ◽  
M. Makki
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Theoretical Background ◽  
Brain Diseases ◽  
Brain Maturation ◽  
White Matter Tracts ◽  
Diffusion Characteristics ◽  
Apparent Diffusion ◽  
Data Acquisition And Processing

Diffusion tensor imaging (DTI), is a new MR-based technique allowing, in-vivo, the assessment of the water diffusive transport in cerebral tissues, depending on the molecular and biochemical environment. Over the past decade, DTI has become an indispensable part of the MR evaluation of pediatric brain in the clinical practice. Quantitative analysis of fractional anisotropy (FA) and apparent diffusion coefficient (ADC), the two most common indices used to describe the diffusion characteristics, helps the comprehension of the childhood brain maturation and enables the early detection of several brain diseases. DTI also allows us to look at anisotropic diffusion within white matter tracts. To better demonstrate the location and orientation of the white matter tracts, new and/or more sophisticated methods such as Color-Encoded Map and Fiber Tracking have been proposed. We review the theoretical background of DT-MRI, the modality of its data acquisition and processing and some of its commonest applications, particularly in Pediatric Neuroradiology.

scholarly journals White Matter Changes in Bipolar Disorder, Alzheimer Disease, and Mild Cognitive Impairment: New Insights from DTI

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Aikaterini Xekardaki ◽  
Panteleimon Giannakopoulos ◽  
Sven Haller
Keyword(s):  
Bipolar Disorder ◽  
White Matter ◽  
Alzheimer Disease ◽  
Structural Changes ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Basic Principles ◽  
Diffusion In Brain ◽  
Diffusion Tensor Imaging Dti

Neuropathological and neuroimaging studies have reported significant changes in white matter in psychiatric and neurodegenerative diseases. Diffusion tensor imaging (DTI), a recently developed technique, enables the detection of microstructural changes in white matter. It is a noninvasivein vivotechnique that assesses water molecules' diffusion in brain tissues. The most commonly used parameters are axial and radial diffusivity reflecting diffusion along and perpendicular to the axons, as well as mean diffusivity and fractional anisotropy representing global diffusion. Although the combination of these parameters provides valuable information about the integrity of brain circuits, their physiological meaning still remains controversial. After reviewing the basic principles of DTI, we report on recent contributions that used this technique to explore subtle structural changes in white matter occurring in elderly patients with bipolar disorder and Alzheimer disease.

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