Healthy brain aging involves changes in both brain structure and function, including alterations in cellular composition and microstructure across brain regions. Unlike diffusion-weighted MRI (dMRI), diffusion-weighted MR spectroscopy (dMRS) can assess cell-type specific microstructural changes, providing indirect information on both cell composition and microstructure through the quantification and interpretation of metabolites' diffusion properties. This work investigates age-related changes in the higher-order diffusion properties of total N-Acetyl-aspartate (neuronal biomarker), total choline (glial biomarker), and total creatine (both neuronal and glial biomarker) beyond the classical apparent diffusion coefficient in cerebral and cerebellar gray matter of healthy human brain. Twenty-five subjects were recruited and scanned using a diffusion-weighted semi-LASER sequence in two brain regions-of-interest (ROI) at 3T: posterior-cingulate (PCC) and cerebellar cortices. Metabolites' diffusion was characterized by quantifying metrics from both Gaussian and non-Gaussian signal representations and biophysical models. All studied metabolites exhibited lower apparent diffusivities and higher apparent kurtosis values in the cerebellum compared to the PCC, likely stemming from the higher microstructural complexity of cellular composition in the cerebellum. Multivariate regression analysis (accounting for ROI tissue composition as a covariate) showed slight decrease (or no change) of all metabolites' diffusivities and slight increase of all metabolites' kurtosis with age, none of which statistically significant (p > 0.05). The proposed age-trajectories provide benchmarks for identifying anomalies in the diffusion properties of major brain metabolites which could be related to pathological mechanisms altering both the brain microstructure and cellular composition.
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Comput Med Imaging Graph
December 2024
Nantes Université, Centrale Nantes, CNRS, LS2N, UMR 6004, F-44000 Nantes, France.
Diffuse Large B-cell Lymphoma (DLBCL) is a lymphatic cancer of steadily growing incidence. Its diagnostic and follow-up rely on the analysis of clinical biomarkers and 18F-Fluorodeoxyglucose (FDG)-PET/CT images. In this context, we target the problem of assisting in the early identification of high-risk DLBCL patients from both images and tabular clinical data.
View Article and Find Full Text PDFNano Lett
January 2025
University Paris-Saclay, CNRS, Laboratoire de Physique des Solides, Orsay 91405, France.
Thermal transport in nanostructures plays a critical role in modern technologies. As devices shrink, techniques that can measure thermal properties at nanometer and nanosecond scales are increasingly needed to capture transient, out-of-equilibrium phenomena. We present a novel pump-probe photon-electron method within a scanning transmission electron microscope (STEM) to map temperature dynamics with unprecedented spatial and temporal resolutions.
View Article and Find Full Text PDFAging Cell
January 2025
Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK.
Healthy brain aging involves changes in both brain structure and function, including alterations in cellular composition and microstructure across brain regions. Unlike diffusion-weighted MRI (dMRI), diffusion-weighted MR spectroscopy (dMRS) can assess cell-type specific microstructural changes, providing indirect information on both cell composition and microstructure through the quantification and interpretation of metabolites' diffusion properties. This work investigates age-related changes in the higher-order diffusion properties of total N-Acetyl-aspartate (neuronal biomarker), total choline (glial biomarker), and total creatine (both neuronal and glial biomarker) beyond the classical apparent diffusion coefficient in cerebral and cerebellar gray matter of healthy human brain.
View Article and Find Full Text PDFJ Am Heart Assoc
January 2025
Department of Neurosurgery, Center of Pituitary Tumor, Ruijin Hospital Shanghai Jiao Tong University School of Medicine Shanghai China.
Background: Carotid endarterectomy (CEA) is widely used to treat carotid artery stenosis (CAS). However, the effects of CEA on unilateral CAS-induced cognitive impairment and the underlying mechanism remain poorly understood.
Methods And Results: Thirteen patients diagnosed with unilateral severe CAS underwent pre- and post-CEA assessments, including fluoro-2-deoxy-d-glucose positron emission tomography/magnetic resonance imaging, cognitive assessments, and routine blood tests before and after CEA.
Mater Horiz
January 2025
Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Germany.
Two-dimensional transition metal dichalcogenides (2D TMDCs) can be combined with organic semiconductors to form hybrid van der Waals heterostructures. Specially, non-fullerene acceptors (NFAs) stand out due to their excellent absorption and exciton diffusion properties. Here, we couple monolayer tungsten diselenide (ML-WSe) with two well performing NFAs, ITIC, and IT-4F (fluorinated ITIC) to achieve hybrid architectures.
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