Imaging of the pial arterial vasculature of the human brain in vivo using high-resolution 7T time-of-flight angiography

eLife, Journal Year: 2022, Volume and Issue: 11

Published: April 29, 2022

The pial arterial vasculature of the human brain is only blood supply to neocortex, but quantitative data on morphology and topology these mesoscopic arteries (diameter 50–300 µm) remains scarce. Because it commonly assumed that flow velocities in vessels are prohibitively slow, non-invasive time-of-flight magnetic resonance angiography (TOF-MRA)—which well suited high 3D imaging resolutions—has not been applied arteries. Here, we provide a theoretical framework outlines how TOF-MRA can visualize small vivo, by employing extremely voxels at size individual vessels. We then evidence for this theory 140 µm isotropic resolution using 7 Tesla (T) (MRI) scanner prospective motion correction, show one voxel width diameter be detected. conclude limited slow flow, instead achievable image resolution. This study represents first targeted, comprehensive account vivo brain. ultra-high-resolution will enable characterization vascular anatomy across investigate patterns relationships between functional architecture.

Language: Английский

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Blood-based biomarkers of cerebral small vessel disease

Ageing Research Reviews, Journal Year: 2024, Volume and Issue: 95, P. 102247 - 102247

Published: Feb. 27, 2024

Age-associated cerebral small vessel disease (CSVD) represents a clinically heterogenous condition, arising from diverse microvascular mechanisms. These lead to chronic cerebrovascular dysfunction and carry substantial risk of subsequent stroke vascular cognitive impairment in aging populations. Owing advances neuroimaging, vivo visualization vasculature abnormities detection CSVD, including lacunes, microinfarcts, microbleeds white matter lesions, is now possible, but remains resource-, skills- time-intensive approach. As result, there has been recent proliferation blood-based biomarker studies for CSVD aimed at developing accessible screening tools early stratification. However, good understanding the pathophysiological processes underpinning needed identify assess useful biomarkers. Here, we provide an overview associated with pathogenesis, endothelial injury dysfunction, neuroinflammation, oxidative stress, perivascular neuronal damage as well cardiovascular dysfunction. Then, review clinical key biomolecules involved aforementioned processes. Lastly, outline future trends directions discovery validation.

Language: Английский

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Functional ultrasound imaging of human brain activity through an acoustically transparent cranial window

Science Translational Medicine, Journal Year: 2024, Volume and Issue: 16(749)

Published: May 29, 2024

Visualization of human brain activity is crucial for understanding normal and aberrant function. Currently available neural recording methods are highly invasive, have low sensitivity, cannot be conducted outside an operating room. Functional ultrasound imaging (fUSI) emerging technique that offers sensitive, large-scale, high-resolution imaging; however, fUSI performed through the adult skull. Here, we used a polymeric skull replacement material to create acoustic window compatible with monitor in single individual. Using vitro cerebrovascular phantom mimic vasculature vivo rodent cranial defect model, first, evaluated signal intensity signal-to-noise ratio polymethyl methacrylate (PMMA) implants different thicknesses or titanium mesh implant. We found rat could recorded high sensitivity PMMA implant using dedicated pulse sequence. then designed custom ultrasound-transparent patient undergoing reconstructive surgery after traumatic injury. showed record awake In video game “connect dots” task, demonstrated mapping decoding task-modulated cortical this guitar-strumming mapped additional task-specific responses. Our proof-of-principle study shows can as (200 μm) functional modality measuring acoustically transparent window.

Language: Английский

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Brain Vascular Health in ALS Is Mediated through Motor Cortex Microvascular Integrity

Cells, Journal Year: 2023, Volume and Issue: 12(6), P. 957 - 957

Published: March 21, 2023

Brain vascular health appears to be critical for preventing the development of amyotrophic lateral sclerosis (ALS) and slowing its progression. ALS patients often demonstrate cardiovascular risk factors commonly suffer from cerebrovascular disease, with evidence pathological alterations in their small cerebral blood vessels. Impaired brain has detrimental effects on motor neurons: endothelial growth factor levels are lowered ALS, which can compromise cell formation integrity blood–brain barrier. Increased turnover neurovascular unit cells precedes senescence, which, together pericyte alterations, further fosters failure toxic metabolite removal. We here provide a comprehensive overview pathogenesis impaired how novel magnetic resonance imaging techniques aid detection. In particular, we discuss patterns supply cortex number branches anterior middle arteries acting as marker resistance resilience against downstream events ALS. outline certain interventions adapted patient needs capabilities have potential mechanistically target microvasculature towards favorable patterns. Through this strategy, aim guide approaches management better understanding pathophysiology.

Language: Английский

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Insights into hippocampal perfusion using high-resolution, multi-modal 7T MRI

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(11)

Published: March 6, 2024

We present a comprehensive study on the non-invasive measurement of hippocampal perfusion. Using high-resolution 7 tesla arterial spin labeling (ASL) data, we generated robust perfusion maps and observed significant variations in among subfields, with CA1 exhibiting lowest levels. Notably, these differences were already detectable 50 perfusion-weighted images per subject, acquired 5 min. To understand underlying factors, examined influence image quality metrics, various tissue microstructure morphometric properties, macrovasculature, cytoarchitecture. higher regions located closer to arteries, demonstrating vascular proximity Moreover, ex vivo cytoarchitectonic features based neuronal density appeared correlate stronger than measures like gray matter thickness. These findings emphasize interplay between microvasculature, metabolic demand shaping Our expands current understanding physiology its relevance neurological disorders. By providing evidence our have implications for diagnosis potential therapeutic interventions. In conclusion, provides valuable resource extensively characterizing

Language: Английский

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Mesoscopic in vivo human T2* dataset acquired using quantitative MRI at 7 Tesla

NeuroImage, Journal Year: 2022, Volume and Issue: 264, P. 119733 - 119733

Published: Nov. 12, 2022

Mesoscopic (0.1-0.5 mm) interrogation of the living human brain is critical for advancing neuroscience and bridging resolution gap with animal models. Despite variety MRI contrasts measured in recent years at mesoscopic scale, vivo quantitative imaging T2* has not been performed. Here we provide a dataset containing empirical measurements acquired 0.35 × mm3 voxel using 7 Tesla MRI. To demonstrate unique features high quality this dataset, generate flat map visualizations that reveal fine-scale cortical substructures such as layers vessels, report depth-dependent (as well R2*) values primary visual cortex auditory are highly consistent across subjects. This freely available https://doi.org/10.17605/OSF.IO/N5BJ7, may prove useful anatomical investigations brain, improving our understanding basis T2*-weighted (f)MRI signal.

Language: Английский

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Germany’s journey toward 14 Tesla human magnetic resonance

Magnetic Resonance Materials in Physics Biology and Medicine, Journal Year: 2023, Volume and Issue: 36(2), P. 191 - 210

Published: April 8, 2023

Abstract Multiple sites within Germany operate human MRI systems with magnetic fields either at 7 Tesla or 9.4 Tesla. In 2013, these formed a network to facilitate and harmonize the research being conducted different make this technology available larger community of researchers clinicians not only Germany, but also worldwide. The German Ultrahigh Field Imaging (GUFI) has defined strategic goal establish 14 whole-body system as national resource in next progression field strength. This paper summarizes history initiative, current status, motivation for pursuing MR imaging spectroscopy such high strength, technical funding challenges involved. It focuses on scientific science policy process from perspective is intended be comprehensive systematic review benefits higher strengths.

Language: Английский

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Segmentation of supragranular and infragranular layers in ultra-high-resolution 7T ex vivo MRI of the human cerebral cortex

Cerebral Cortex, Journal Year: 2024, Volume and Issue: 34(9)

Published: Aug. 19, 2024

Accurate labeling of specific layers in the human cerebral cortex is crucial for advancing our understanding neurodevelopmental and neurodegenerative disorders. Building on recent advancements ultra-high-resolution ex vivo MRI, we present a novel semi-supervised segmentation model capable identifying supragranular infragranular MRI with unprecedented precision. On dataset consisting 17 whole-hemisphere scans at 120 $\mu $m, propose Multi-resolution U-Nets framework that integrates global local structural information, achieving reliable maps entire hemisphere, Dice scores over 0.8 supra- layers. This enables surface modeling, atlas construction, anomaly detection disease states, cross-modality validation while also paving way finer layer segmentation. Our approach offers powerful tool comprehensive neuroanatomical investigations holds promise mechanistic progression diseases.

Language: Английский

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Mapping vascular network architecture in primate brain using ferumoxytol-weighted laminar MRI

Published: Jan. 24, 2025

Mapping the vascular organization of brain is great importance across various domains basic neuroimaging research, diagnostic radiology, and neurology. However, intricate task precisely mapping vasculature regions cortical layers presents formidable challenges, resulting in a limited understanding neurometabolic factors influencing brain’s microvasculature. Addressing this gap, our study investigates whole-brain volume using ferumoxytol-weighted laminar-resolution multi-echo gradient-echo imaging macaque monkeys. We validate results with published data for densities compare them cytoarchitecture, neuron synaptic densities. The ferumoxytol-induced change transverse relaxation rate (ΔR 2 *), an indirect proxy measure cerebral blood (CBV), was mapped onto twelve equivolumetric laminar surfaces. Our findings reveal that CBV varies 3-fold brain, highest observed inferior colliculus lowest corpus callosum. In cortex, notably high early primary sensory areas low association responsible higher cognitive functions. Classification into distinct groups unveils extensive replication translaminar network motifs, suggesting computational energy supply requirements varying cytoarchitecture types. Regionally, baseline R * exhibit positive correlations density negative receptor Adjusting image resolution based on critical sampling frequency penetrating vessels allows us to delineate approximately 30% arterial-venous vessels. Collectively, these mark significant methodological conceptual advancements, contributing refinement cerebrovascular MRI. Furthermore, establishes linkage between architecture primate brain.

Language: Английский

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Characterizing positive and negative quantitative susceptibility values in the cortex following mild traumatic brain injury: a depth- and curvature-based study

Cerebral Cortex, Journal Year: 2025, Volume and Issue: 35(3)

Published: March 1, 2025

Abstract Evidence has linked head trauma to increased risk factors for neuropathology, including mechanical deformation of the sulcal fundus and, later, perivascular accumulation hyperphosphorylated tau adjacent these spaces related chronic traumatic encephalopathy. However, little is known about microstructural abnormalities and cellular dyshomeostasis in acute mild brain injury humans, particularly cortex. To address this gap, we designed first architectonically motivated quantitative susceptibility mapping study assess regional patterns net positive (iron-related) negative (myelin-, calcium-, protein-related) magnetic across 34 cortical regions interest following injury. Bilateral, between-group analyses sensitive depth curvature were conducted between 25 males with (<14 d) sports-related age-matched male controls. Results suggest a trauma-induced increase focal superficial, perivascular-adjacent parahippocampal sulcus. Decreases values distinct voxel populations within same region indicate potential dual pathology neural substrates. These injury–related from age-related processes revealed by correlation analyses. Our findings depth- curvature-specific deposition biological substrates tissue convergent features misfolded proteins trauma-related neurodegeneration.

Language: Английский

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