Exploring Radial Asymmetry in MR Diffusion Tensor Imaging and Its Impact on the Interpretation of Glymphatic Mechanisms

Journal of Magnetic Resonance Imaging, Journal Year: 2023, Volume and Issue: 60(4), P. 1432 - 1441

Published: Dec. 29, 2023

Background Diffusion imaging holds great potential for the non‐invasive assessment of glymphatic system in humans. One technique, diffusion tensor along perivascular space (DTI‐ALPS), has introduced ALPS‐index, a novel metric evaluating diffusivity within space. However, it still needs to be established whether observed reduction ALPS‐index reflects axonal changes, common occurrence neurodegenerative diseases. Purpose To determine alterations can influence change ALPS‐index. Study Type Retrospective. Population 100 participants (78 cognitively normal and 22 with mild cognitive impairments) aged 50–90 years old. Field Strength/Sequence 3T; diffusion‐weighted single‐shot spin‐echo echo‐planar sequence, T1‐weighted images (MP‐RAGE). Assessment The ratio two radial diffusivities (i.e., λ2/λ3) across major white matter tracts distinct venous/perivenous anatomy that fulfill (ALPS‐tracts) do not (control tracts) anatomical assumptions were analyzed. Statistical Tests investigate correlation between λ2/λ3 age/cognitive function (RAVLT) while accounting effect age, linear regression was implemented remove age from each variable. Pearson analysis conducted on residuals obtained regression. significance set at p < 0.05. Results λ2 ~50% higher than λ3 demonstrated consistent pattern both ALPS control tracts. Additionally, advancing ( r = −0.39, −0.29, association forceps tract, respectively) decreased memory 0.24, 0.27, respectively). Data Conclusions results unveil widespread asymmetry changes aging neurodegeration. These findings highlight may solely reflect but also incorporate contributions. Level Evidence 3 Technical Efficacy Stage 2

Language: Английский

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A critical guide to the automated quantification of perivascular spaces in magnetic resonance imaging

Frontiers in Neuroscience, Journal Year: 2022, Volume and Issue: 16

Published: Dec. 14, 2022

The glymphatic system is responsible for waste clearance in the brain. It comprised of perivascular spaces (PVS) that surround penetrating blood vessels. These are filled with cerebrospinal fluid and interstitial fluid, can be seen magnetic resonance imaging. Various algorithms have been developed to automatically label these MRI. This has enabled volumetric morphological analyses PVS healthy disease cohorts. However, there remain inconsistencies between measures reported by different methods automated segmentation. present review emphasizes importance voxel-wise evaluation model performance, mainly Sørensen Dice similarity coefficient. Conventional count correlations validation inadequate if goal assess or PVS. downside it requires manual segmentations require large amounts time produce. One possible solution derive semi-automatically. Additionally, recommendations made facilitate rigorous development segmentation models. In application tools, publication image quality metrics, such as contrast-to-noise ratio, alongside descriptive statistics volumes counts will comparability studies. Lastly, a head-to-head comparison two algorithms, applied cohorts astronauts reveals how results differ substantially techniques.

Language: Английский

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Diffusion Tensor Imaging Along Perivascular Spaces (DTI-ALPS) to Assess Effects of Age, Sex, and Head Size on Interstitial Fluid Dynamics in Healthy Subjects

Journal of Alzheimer s Disease Reports, Journal Year: 2024, Volume and Issue: 8(1), P. 355 - 361

Published: Feb. 20, 2024

Diffusion tensor imaging along perivascular spaces (DTI-ALPS) is a novel MRI method for assessing brain interstitial fluid dynamics, potentially indexing glymphatic function. Failed clearance implicated in Alzheimer’s disease (AD) pathophysiology. We assessed the contribution of age and female sex (strong AD risk factors) to DTI-ALPS index healthy subjects. also first time effect head size. In accord with prior studies, we show reduced aging, men compared women. However, size may be major contributing factor this counterintuitive difference.

Language: Английский

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Glymphatic System Dysfunction Underlying Schizophrenia Is Associated With Cognitive Impairment

Schizophrenia Bulletin, Journal Year: 2024, Volume and Issue: 50(5), P. 1223 - 1231

Published: April 6, 2024

Abstract Background and Hypothesis Despite the well-documented structural functional brain changes in schizophrenia, potential role of glymphatic dysfunction remains largely unexplored. This study investigates system’s function utilizing diffusion tensor imaging (DTI) to analyze water along perivascular space (ALPS), examines its correlation with clinical symptoms. Study Design A cohort consisting 43 people schizophrenia 108 healthy controls was examined. We quantified metrics x-, y-, z-axis both projection association fibers derive DTI-ALPS index, a proxy for activity. The differences ALPS index between groups were analyzed using 2-way ANCOVA controlling age sex, while partial correlations assessed variables. Results People showed significantly reduced across whole within hemispheres (F = 9.001, P .011; F 10.024, 5.927, .044; false discovery rate corrected), indicating schizophrenia. group by cognitive performance interaction effects on not observed. Moreover, lower associated poorer specific neuropsychological tests Conclusion Our highlights correlated more pronounced impairments. suggests that may contribute pathophysiology offering new insights into underlying mechanisms.

Language: Английский

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Novel developments in non-contrast enhanced MRI of the perivascular clearance system: What are the possibilities for Alzheimer’s disease research?

Neuroscience & Biobehavioral Reviews, Journal Year: 2022, Volume and Issue: 144, P. 104999 - 104999

Published: Dec. 15, 2022

The cerebral waste clearance system (i.e, glymphatic or intramural periarterial drainage) works through a network of perivascular spaces (PVS). Dysfunction this likely contributes to aggregation Amyloid-β and subsequent toxic plaques in Alzheimer's disease (AD). A promising, non-invasive technique study is MRI, though applications dementia are still scarce. This review focusses on recent non-contrast enhanced (non-CE) MRI techniques which determine visualise physiological aspects the at multiple levels, i.e., cerebrospinal fluid flow, PVS-flow interstitial movement. Furthermore, various studies focussing relevant AD discussed, such as ageing, sleep alterations, cognitive decline. Additionally, complementary function non-CE CE methods elaborated upon. We conclude that have great potential parts affected by stages impairment dysfunction occurs, could allow future clinical trials target these specific mechanisms.

Language: Английский

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Dilated Virchow-Robin spaces are a marker for arterial disease in multiple sclerosis

EBioMedicine, Journal Year: 2023, Volume and Issue: 92, P. 104631 - 104631

Published: May 28, 2023

Virchow-Robin spaces (VRS) have been associated with neurodegeneration and neuroinflammation. However, it remains uncertain to what degree non-dilated or dilated VRS reflect specific features of neuroinflammatory pathology. Thus, we aimed at investigating the clinical relevance as imaging biomarker in multiple sclerosis (MS) correlate their histopathologic signature.In a cohort study comprising 142 MS patients 30 control subjects, assessed association magnetic resonance (MRI) outcomes. Findings were corroborated validation 63 patients. Brain blocks from 6 3 non-MS controls histopathologically processed tissue substrate.In our actively treated cohort, count centrum semiovale was increased T1 T2 lesion volumes. There no systematic spatial colocalization lesions. At level, mostly corresponded arteries not pathological hallmarks. Interestingly, ex vivo progressive patients, signs small vessel disease.Contrary prior beliefs, these observations suggest that do associate an accumulation immune cells. But instead, findings indicate vascular pathology driver and/or consequence for this feature.NIH, Swedish Society Medical Research, Swiss National Science Foundation University Zurich.

Language: Английский

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Effects of sleep on brain perivascular space in a cognitively healthy population

Sleep Medicine, Journal Year: 2023, Volume and Issue: 111, P. 170 - 179

Published: Sept. 25, 2023

The magnetic resonance imaging (MRI) visible perivascular space (PVS) reportedly clears amyloid-β and metabolic waste during sleep. Previous studies reported an association between sleep the PVS in small vessel disease, traumatic brain injury, Alzheimer's disease. However, this relationship a healthy cohort is still unclear. Here, we used Human Connectome Project Aging dataset to analyze cognitively adults across aging continuum. We measured parameters using self-reported Pittsburgh Sleep Quality Index questionnaire. found that older who had better quality efficiency presented with larger volume fraction basal ganglia (BG). measures were not associated centrum semiovale (CSO). In addition, body mass index (BMI) influenced BG-PVS middle-aged participants. entire cohort, effect of on was mediated by BMI. BMI did influence cohort. Furthermore, there are significant differences racial/ethnic cohorts. summary, alteration different adults.

Language: Английский

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Overview of the Current Knowledge and Conventional MRI Characteristics of Peri- and Para-Vascular Spaces

Brain Sciences, Journal Year: 2024, Volume and Issue: 14(2), P. 138 - 138

Published: Jan. 28, 2024

Brain spaces around (perivascular spaces) and alongside (paravascular or Virchow–Robin vessels have gained significant attention in recent years due to the advancements of vivo imaging tools their crucial role maintaining brain health, contributing anatomic foundation glymphatic system. In fact, it is widely accepted that peri- para-vascular function as waste clearance pathways for materials such ß-amyloid by allowing exchange between cerebrospinal fluid interstitial fluid. Visible on magnetic resonance are often a normal finding, but they also been associated with wide range neurological systemic conditions, suggesting potential early indicators intracranial pressure neurofluid imbalance. Nonetheless, several aspects these still controversial. This article offers an overview current knowledge characteristics spaces, which can help daily clinical practice image description interpretation. paper organized into different sections, including microscopic anatomy associations pathological physiological events, differential diagnosis.

Language: Английский

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Glymphatic System and Psychiatric Disorders: A Rapid Comprehensive Scoping Review

Current Neuropharmacology, Journal Year: 2024, Volume and Issue: 22(12), P. 2016 - 2033

Published: May 23, 2024

Background: Since discovering the glymphatic system, there has been a looming interest in exploring its relationship with psychiatric disorders. Recently, increasing evidence suggests an involvement of system pathophysiology However, clear data are still lacking. In this context, rapid comprehensive PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension Scoping Reviews) scoping review aims to identify analyze current about relation between Methods: We conducted literature then proceeded discuss findings narratively. Tables were constructed articles sorted according authors, year, title, location study, sample size, disorder, aim principal findings, implications. Results: Twenty papers identified as eligible, among which 2 on Schizophrenia, 1 Autism Spectrum Disorders, Depression, Depression Trauma-related Anxiety, Anxiety Sleep 8 Alcohol use disorder Cocaine Use Disorder. Conclusion: This correlation several disorders: Disorder, Trauma-Related Disorders. Impairment could play role It is important implement research topic adopt standardized markers radio diagnostic tools.

Language: Английский

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3D Quantitative-Amplified Magnetic Resonance Imaging (3D q-aMRI)

Bioengineering, Journal Year: 2024, Volume and Issue: 11(8), P. 851 - 851

Published: Aug. 20, 2024

Amplified MRI (aMRI) is a promising new technique that can visualize pulsatile brain tissue motion by amplifying sub-voxel in cine data, but it lacks the ability to quantify field physical units. Here, we introduce novel post-processing algorithm called 3D quantitative amplified (3D q-aMRI). This enables visualization and quantification of motion. q-aMRI was validated optimized on digital phantom applied

Language: Английский

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