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Multiparametric MRI-based biomarkers in the non-fluent and semantic variants of primary progressive aphasia.

BACKGROUND: The non-fluent (nfPPA) and semantic (svPPA) variants of primary progressive aphasia exhibit distinct clinical features. We investigated whether diffusion tensor imaging (DTI) and atlas-based volumetry (ABV) could reveal divergent patterns of longitudinal changes in brain white matter microstructure and gray matter volumes. METHODS: MRI datasets from 29 nfPPA, 27 svPPA, and 39 controls were analyzed. White matter fractional anisotropy (FA) differences were assessed using unbiased Whole Brain-based Spatial Statistics (WBSS) and Tract-Wise Fractional Anisotropy Statistics (TFAS). Gra…

Brain Microstructure Interrogation by Diffusion Tensor and Kurtosis Imaging in Progressive Supranuclear Palsy Subtypes.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) is commonly used to assess the integrity of gray and white matter (WM) structures in … a Siemens system in 22 patients with PSP-RS, 23 with PSP-P, 19 with PD, and 19 controls. Fractional anisotropy, mean diffusivity, kurtosis fractional anisotropy (KFA), and mean kurtosis (Kmean) were calculated for nine deep gray matter regions and six different WM tracts. RESULTS: DKI identified differences (not found by DTI) between control and PSP groups …

Evaluating regional and global diffusion measures as biomarkers for vascular contributions to cognitive impairment and dementia.

BACKGROUND: Diffusion MRI (dMRI) has been proposed for quantifying early tissue changes in cerebral small vessel disease (SVD). We evaluated … dMRI scans, amyloid-PET, and structural imaging. We computed single-shell dMRI measures (fractional anisotropy, mean diffusivity, free water, peak-width skeletonized mean diffusivity (PSMD) and assessed: i) regional dependance of predictors of baseline WM damage using voxel-level analyses; ii) longitudinal associations between dMRI measures and cognition; an …

Anisotropic ice-templated collagen scaffolds for soft tissue engineering: a mechanical characterisation toolkit.

Collagen-based soft tissues are often anisotropic in structure, and in regenerative medicine, it is important that scaffolds are designed to closely mimic their architecture and mechanical behaviour. Existing testing standards are not directly applicable to anisotropic structures in physiologically relevant conditions. The challenge is therefore to systematically quantify mechanical anisotropy, nonlinear tensile behaviour, and both in vitro degradation and fatigue in a way appropriate for soft, porous, natural macromolecular structures. In this study, we fabricated collagen scaffolds with elon…

The role of low subcortical iron, white matter myelin, and oligodendrocytes in schizophrenia: a quantitative susceptibility mapping and diffusion tensor imaging study.

Iron-the most abundant magnetic brain substance-is essential for many biological processes, including dopamine and myelin synthesis. Quantitative susceptibility mapping (QSM) MRI has recently linked altered subcortical magnetic susceptibility (χ) to schizophrenia. Since χ is increased by iron and decreased by myelin, abnormal levels of either could underlie these QSM differences. In white matter tracts, magnetic susceptibility anisotropy (δχ) serves as a myelin-specific marker that is insensitive to iron content. To clarify the origin of case-control χ differences, we employed QSM in 85 indivi…

Estimating Multimodal Structural Brain Variability in Schizophrenia Spectrum Disorders: A Worldwide ENIGMA Study.

OBJECTIVE: The clinical diversity of schizophrenia is reflected by structural brain variability. It remains unclear how this variability man … rtical thickness, cortical surface area, cortical folding index, subcortical volume, and fractional anisotropy were examined in individuals with schizophrenia and healthy control subjects. RESULTS: Individuals with schizophrenia showed greater variability in cortical thickness, cortical surface area, subcortical volume, and fractional anisotropy within the …

Myelin water and tensor-ценное диффузионное изображение: (Как) они связаны?

ЦЕЛЬ: Обычное МРТ дает ограниченное представление о конкретных характеристиках тканей центральной нервной системы, в то время как количественные показатели МРТ могут дать более подробную информацию о различных аспектах микроструктуры. Многомерный подход, предусматривающий принятие многочисленных количественных показателей, может улучшить наше понимание здоровой ткани и патологии. Предыдущая работа показывает, что миелинская доля воды (MWF) связана с фракцией анизотропии (FA), однако эта взаимосвязь осложняется смешивающими факторами, которые могут быть устранены с помощью снимков, полученных с

Совпадение в аннотации оригинала
PURPOSE: Conventional MRI offers limited insight into specific characteristics of central nervous system tissue, whereas quantitative MRI me … lthy tissue and pathology. Previous work shows myelin water fraction (MWF) is related to fractional anisotropy (FA), but this relationship is complicated by confounding factors that may be resolved using tensor-valued diffusion imaging, which yields measurements of microscopic FA (μFA) and tissue heterogeneity (CMD). Our aims were to better understand how me …

Diffusion Tensor Imaging in Parenchymal Neuro-Behçet's Disease.

INTRODUCTION: Parenchymal Neuro-Behçet's disease (p-NBD) usually presents with a characteristic lesion in the mesodiencephalic region. However, there is a lack of information regarding the axonal integrity of normal-appearing white matter in p-NBD. Diffusion tensor imaging (DTI) is based on the properties of diffusivity and anisotropy that indicate the integrity of axons. The primary objective of the study was to compare p-NBD patients to healthy controls using diffusion tensor magnetic resonance imaging (DTI-MRI). METHODS: The study enrolled parenchymal p-NBD patients who maintained stable d…

Microstructure and Perfusion Alterations of Globus Pallidus in Neonates with Hyperbilirubinemia.

BACKGROUND: Previous studies have indicated the abnormality of the globus pallidus in neonates with hyperbilirubinemia. OBJECTIVE: This stu … llidus were calculated from DTI, including the Apparent Diffusion Coefficient (ADC), the Fractional Anisotropy (FA), and Volume Ratio (VR) values. Additionally, the relative Cerebral Blood Flow (rCBF) values were obtained from ASL. RESULTS: It was observed that the mean DTI signal of globus pallidus was significantly different among the three groups (p < 0. …

Diffusion spectrum imaging in patients with idiopathic normal pressure hydrocephalus: correlation with ventricular enlargement.

BACKGROUND: To investigate the association between white matter changes and ventricular expansion in idiopathic normal pressure hydrocephalus (iNPH) based on diffusion spectrum imaging (DSI). METHODS: We included 32 patients with iNPH who underwent DSI using a 3T MRI scanner. The lateral ventricles were manually segmented, and ventricular volumes were measured. Two methods were utilised in the study: manual region-of-interest (ROI) delineation and tract diffusion profile analysis. General fractional anisotropy (GFA) and fractional anisotropy (FA) were extracted in different white matter regio…

The effect of live music therapy on white matter microstructure in very preterm infants - A randomized controlled trial.

OBJECTIVE: Music therapy (MT) is proposed to enrich the acoustic environment of very preterm infants (VPT) on the neonatal intensive care un … Differences in WM microstructure were assessed using tract based spatial statistics with fractional anisotropy. RESULTS: Of 80 infants enrolled, 42 were eligible for diffusion tensor imaging analysis (MT: n = 22, standard care: n = 20). While primary tract based spatial statistics analysis revealed no significant differences between groups, post hoc analysi …

Diffusion kurtosis imaging reveals abnormal gray matter and white matter development in some brain regions of children with attention-deficit/hyperactivity disorder.

In this study, we explored the application of diffusion kurtosis imaging (DKI) technology in the brains of children with attention-deficit/h … th ADHD than in healthy children (p < .05). The axial kurtosis (Ka), mean kurtosis (MK), fractional anisotropy (FA), and radial kurtosis(Kr) values in the frontal lobe, temporal lobe, and caudate nucleus of children with ADHD were lower than those of healthy children, while the mean diffusivity(MD) and fractional anisotropy of kurtosis (FAK) values were high …

Utility of Diffusion Tensor Imaging in Preterm Infants with Germinal Matrix Hemorrhage and Intraventricular Hemorrhage: A Systematic Review.

OBJECTIVE: Intraventricular hemorrhage (IVH) and germinal matrix hemorrhage (GMH) are the most common brain injuries in preterm infants. Neo … There were 574 preterm infants with GMH-IVH on DTI. Twelve studies documented decreased fractional anisotropy, whereas 6 demonstrated structural segregation and asymmetrical white matter myelination in these infants. Seven studies documented concurrent CUS use with 2 studies comparing DTI findings with CUS findings. In both studies, DTI more accurately dete …

Comparison of distortion correction preprocessing pipelines for DTI in the upper limb.

PURPOSE: DTI characterizes tissue microstructure and provides proxy measures of nerve health. Echo-planar imaging is a popular method of acq … Compared to TOPUP & eddy, DSI Studio and TORTOISE generated 2% and 6% lower estimates of fractional anisotropy, and 6% and 13% higher estimates of radial diffusivity, respectively. Estimates of anisotropy from TOPUP & eddy versus TOPUP were not different but TOPUP reduced radial diffusivity by 3%. The agreement of DTI metrics between pipelines was poor. CON …

Characterization of white matter alterations using diffusion kurtosis imaging in patients with amyotrophic lateral sclerosis.

BACKGROUND: To evaluate the degeneration of the corticospinal tract (CST) and corpus callosum (CC) in patients with motor neuron disease and … son to controls, patients had significantly higher mean and radial diffusivity and lower fractional anisotropy (FA), kurtosis anisotropy, mean kurtosis (MK), and radial kurtosis (RK) in the CST and CC (p < .017). Along-the-tract analysis revealed changes concentrated in the posterior limb of the internal capsule, corona radiata, and primary motor cortex (fal …

Resultant inward imbalanced seeding force (RIISF)-induced concave gold nanostar (CAuNS) for non-enzymatic electrocatalytic detection of serotonin and Kynurenine in human serum.

CTAC-based gold nanoseed-induced concave curvature evolution of surface boundary planes from concave gold nanocube (CAuNC) to concave gold nanostar (CAuNS) has been achieved by a novel synthetic methodology simply by controlling the extent of seed used and hence the generated 'Resultant Inward Imbalanced Seeding Force (RIISF)'. The resultant CAuNS shows an excellent enhancement in catalytic activity compared to CAuNC and other intermediates as a function of curvature-induced anisotropy. Detailed characterization evaluates the presence of an enhanced number of multiple defect sites, high energy…

Disrupted White Matter Integrity and Cognitive Functions in Amyloid-β Positive Alzheimer's Disease with Concomitant Lobar Cerebral Microbleeds.

BACKGROUND: Lobar cerebral microbleeds (CMBs), which can impair white matter (WM), are often concomitant with definite Alzheimer's disease ( … 1) >M-CMBs (n = 25) group. Compared to no CMBs, M-CMBs group had significantly decreased fractional anisotropy in left anterior thalamic radiation (ATR), forceps major, forceps minor and inferior longitudinal fasciculus, bilateral inferior fronto-occipital fasciculus (IFOF), and superior longitudinal fasciculus. M-CMBs group also had lower fractional anisotr …

Characterization of white matter microstructural abnormalities associated with cognitive dysfunction in cerebral small vessel disease with cerebral microbleeds.

BACKGROUND: Diffusion tensor imaging (DTI) is recommended as a sensitive method to explore white matter (WM) microstructural alterations. Cerebral small vessel disease (CSVD) may be accompanied by extensive WM microstructural deterioration, while cerebral microbleeds (CMBs) are an important factor affecting CSVD. METHODS: Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) images from 49 CSVD patients with CMBs (CSVD-c), 114 CSVD patients without CMBs (CSVD-n), and 83 controls were analyzed using DTI-derived tract-based spatial statistics to d…

Layer-specific microstructural patterns of anterior hippocampus in Alzheimer's disease with ex vivo diffusion MRI at 14.1 T.

High-resolution ex vivo diffusion MRI (dMRI) can provide exquisite mesoscopic details and microstructural information of the human brain. Mi … tures in different layers and subfields of anterior hippocampus. In the HC samples, we found higher anisotropy, lower diffusivity, and more streamlines in the layers within cornu ammonis (CA) than those within dentate gyrus (DG). Comparisons between disease groups showed that (1) anisotropy measurements in the CA layers of AD, especially stratum lacunosum (S …

White Matter Connectivity in Incident Mild Cognitive Impairment: A Diffusion Spectrum Imaging Study of World Trade Center Responders at Midlife.

BACKGROUND: Individuals who participated in response efforts at the World Trade Center (WTC) following 9/11/2001 are experiencing elevated i … e. Connectometry examined whole-brain tract-level differences in white matter integrity. Fractional anisotropy (FA), mean diffusivity (MD), and quantified anisotropy were extracted for region of interest (ROI) analyses using the Desikan-Killiany atlas. RESULTS: Connectometry identified both increased and decreased connectivity within regions of the brains o …