dMRI: Diffusion Magnetic Resonance Imaging as a Window onto Structural Brain Networks and White Matter Microstructure

2021 ◽  
pp. 105-134
Author(s):  
Alard Roebroeck
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Magnetic Resonance Imaging ◽  
Brain Networks ◽  
Resonance Imaging ◽  
White Matter Microstructure ◽  
Structural Brain

scholarly journals Detecting microstructural deviations in individuals with deep diffusion MRI tractometry

2021 ◽  
Vol 1 (9) ◽  
pp. 598-606
Author(s):  
Maxime Chamberland ◽  
Sila Genc ◽  
Chantal M. W. Tax ◽  
Dmitri Shastin ◽  
Kristin Koller ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Magnetic Resonance Imaging ◽  
Unmet Need ◽  
Current Approach ◽  
Resonance Imaging ◽  
Traditional Group ◽  
Individual Level ◽  
The Individual

AbstractMost diffusion magnetic resonance imaging studies of disease rely on statistical comparisons between large groups of patients and healthy participants to infer altered tissue states in the brain; however, clinical heterogeneity can greatly challenge their discriminative power. There is currently an unmet need to move away from the current approach of group-wise comparisons to methods with the sensitivity to detect altered tissue states at the individual level. This would ultimately enable the early detection and interpretation of microstructural abnormalities in individual patients, an important step towards personalized medicine in translational imaging. To this end, Detect was developed to advance diffusion magnetic resonance imaging tractometry towards single-patient analysis. By operating on the manifold of white-matter pathways and learning normative microstructural features, our framework captures idiosyncrasies in patterns along white-matter pathways. Our approach paves the way from traditional group-based comparisons to true personalized radiology, taking microstructural imaging from the bench to the bedside.

scholarly journals Diffusion magnetic resonance imaging assessment of regional white matter maturation in preterm neonates

2020 ◽  
Author(s):  
J. A. Kimpton ◽  
D. Batalle ◽  
M. L. Barnett ◽  
E. J. Hughes ◽  
A. T. M. Chew ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Magnetic Resonance Imaging ◽  
Diffusion Tensor ◽  
Brain Mri ◽  
Preterm Neonates ◽  
Resonance Imaging ◽  
Neurodevelopmental Outcomes ◽  
Optic Radiations

Abstract Purpose Diffusion magnetic resonance imaging (dMRI) studies report altered white matter (WM) development in preterm infants. Neurite orientation dispersion and density imaging (NODDI) metrics provide more realistic estimations of neurite architecture in vivo compared with standard diffusion tensor imaging (DTI) metrics. This study investigated microstructural maturation of WM in preterm neonates scanned between 25 and 45 weeks postmenstrual age (PMA) with normal neurodevelopmental outcomes at 2 years using DTI and NODDI metrics. Methods Thirty-one neonates (n = 17 male) with median (range) gestational age (GA) 32+1 weeks (24+2–36+4) underwent 3 T brain MRI at median (range) post menstrual age (PMA) 35+2 weeks (25+3–43+1). WM tracts (cingulum, fornix, corticospinal tract (CST), inferior longitudinal fasciculus (ILF), optic radiations) were delineated using constrained spherical deconvolution and probabilistic tractography in MRtrix3. DTI and NODDI metrics were extracted for the whole tract and cross-sections along each tract to assess regional development. Results PMA at scan positively correlated with fractional anisotropy (FA) in the CST, fornix and optic radiations and neurite density index (NDI) in the cingulum, CST and fornix and negatively correlated with mean diffusivity (MD) in all tracts. A multilinear regression model demonstrated PMA at scan influenced all diffusion measures, GA and GAxPMA at scan influenced FA, MD and NDI and gender affected NDI. Cross-sectional analyses revealed asynchronous WM maturation within and between WM tracts.). Conclusion We describe normal WM maturation in preterm neonates with normal neurodevelopmental outcomes. NODDI can enhance our understanding of WM maturation compared with standard DTI metrics alone.

Abstract P349: Neuroprotective Effects of L-Carnitine on Vascular Dementia in Hemodialysis Patients

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Yuji Ueno ◽  
Takao Urabe ◽  
Nobutaka Hattori
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cognitive Impairment ◽  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Magnetic Resonance Imaging ◽  
Hemodialysis Patients ◽  
Resonance Imaging ◽  
Short Term ◽  
Microstructural Damage

Background and purpose: L-carnitine alleviated oxidative stress and white matter lesions in an experimental study. Cognitive decline is not uncommon in hemodialysis patients, the pathogenesis of which has not been elucidated. Methods: Using novel diffusion magnetic resonance imaging techniques, white matter microstructural changes and cognitive decline in hemodialysis patients, and the effects of l-carnitine on such disorders were investigated. Fourteen hemodialysis patients underwent diffusion tensor imaging, diffusion kurtosis imaging, neurite orientation dispersion and density imaging, and laboratory and neuropsychological tests, which were compared between two groups based on the duration of l-carnitine treatment: (1) no or short-term l-carnitine treatment; and (2) long-term l-carnitine treatment. Ten age and sex-matched controls were enrolled. Results: On neuropsychological testing, the majority of hemodialysis patients were categorized as having mild cognitive impairment. Seven patients were classified into the no or short-term l-carnitine treatment and long-term l-carnitine treatment groups. Compared to controls, microstructural disorders of white matter were widely detected in no or short-term l-carnitine treatment on diffusion magnetic resonance imaging. An autopsy study from the no or short-term l-carnitine treatment group showed rarefaction of myelinated fibers in white matter. In long-term l-carnitine treatment, microstructural damage on diffusion magnetic resonance imaging was alleviated along with lower levels of high-sensitivity C-reactive protein ( P <0.001) and substantial increases of carnitine levels ( P <0.001). The long-term l-carnitine treatment group showed better achievement in Trail Making Test-A ( P =0.017), which was correlated with amelioration of disorders in bilateral anterior thalamic radiations, the left cingulum in the cingulate gyrus, the right superior longitudinal fasciculus, and the forceps major ( P <0.05). Conclusion: Novel diffusion magnetic resonance imaging tractography detected abnormalities of white matter tracts in hemodialysis patients. Long-term treatment with l-carnitine alleviated white matter microstructural damage and cognitive impairment.

Limbic and Callosal White Matter Changes in Euthymic Bipolar I Disorder: An Advanced Diffusion Magnetic Resonance Imaging Tractography Study

2013 ◽  
Vol 73 (2) ◽  
pp. 194-201 ◽  
Author(s):  
Louise Emsell ◽  
Alexander Leemans ◽  
Camilla Langan ◽  
Wim Van Hecke ◽  
Gareth J. Barker ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Magnetic Resonance Imaging ◽  
Resonance Imaging ◽  
White Matter Changes ◽  
Bipolar I Disorder
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