Stokes flows in a two-dimensional bifurcation

Royal Society Open Science, Год журнала: 2025, Номер 12(1)

Опубликована: Янв. 1, 2025

The flow network model is an established approach to approximate pressure–flow relationships in a bifurcating network, and has been widely used many contexts. Existing models typically assume unidirectional exploit Poiseuille’s law, thus neglect the impact of bifurcation geometry finite-sized objects on flow. We determine by computing Stokes flows two-dimensional (2D) using Lightning-AAA Rational algorithm, novel mesh-free algorithm for solving 2D problems utilizing applied complex analysis based rational approximation Goursat functions. compute conductances bifurcations with different channel widths, angles, curved boundary geometries fixed circular objects. quantify difference between computed their Poiseuille law approximations demonstrate importance incorporating detailed into existing models. parametrize as functions dimensionless parameters object machine learning approach, which simple use provides more accurate than law. Finally, details are presented.

Язык: Английский

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A review of brain injury at multiple time scales and its clinicopathological correlation through in silico modeling

Brain Multiphysics, Год журнала: 2024, Номер 6, С. 100090 - 100090

Опубликована: Янв. 21, 2024

Understanding the correlation between pathological changes and type of brain injury is pivotal in mitigating damage planning reliable improved treatment strategies. Swift identification underlying mechanisms behind essential for early diagnosis, surgical planning, post-operative therapies. Brain may stem from various sources, including trauma (resulting traumatic injury), (leading to neurodegenerative mechanisms. These injuries can manifest spatially, affecting individual neurons entire organ temporally, ranging immediate long-term degeneration. However, direct evidence linking short tissue human population limited, posing challenges establishing a clear clinicopathological connection. Recently, silico modeling has emerged as cost-effective approach that assist clinicians gaining deeper insights uncover new pathways. Physics machine learning-based offers valuable contributions prevention, prognosis, patient monitoring, especially given complexities acquiring patient-specific clinical data related injuries. Considering spatiotemporal complexity damage, developing comprehensive, multiscale, multiphysics model imperative better understanding. This study aims categorize explore strategies across three distinct time scales, review at length recommend development comprehensive biomechanical integrates multimodal multiphysics. Such an integrated will provide personalized diagnosis tailored patients. Statement Significance The connection observations pathology crucial managing result via diverse factors organs, initial neurodegeneration. limited hinders connections. In modeling, utilizing physics principles, aid uncovering A multimodal, vital understanding complex damage. categorizes strategies, reviews recommends models treatment.

Язык: Английский

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On the Sensitivity Analysis of Porous Finite Element Models for Cerebral Perfusion Estimation

Annals of Biomedical Engineering, Год журнала: 2021, Номер 49(12), С. 3647 - 3665

Опубликована: Июнь 21, 2021

Computational physiological models are promising tools to enhance the design of clinical trials and assist in decision making. Organ-scale haemodynamic gaining popularity evaluate perfusion a virtual environment both healthy diseased patients. Recently, principles verification, validation, uncertainty quantification such have been laid down ensure safe applications engineering software medical device industry. The present study sets out establish guidelines for usage three-dimensional steady state porous cerebral model human brain following detailed verification validation (V&V 40) standard American Society Mechanical Engineers. relies on finite element method has developed specifically estimate how is altered ischaemic stroke patients before, during, after treatments. Simulations compared with exact analytical solutions thorough sensitivity analysis presented covering every numerical parameter. results suggest that can approximate blood pressure distributions reliably even coarse grid first order elements. On other hand, higher elements essential mitigate errors volumetric flow rate estimation through cortical surface regions. Matching corresponding major arteries identified as milestone. It found inlet velocity boundary conditions hard obtain constant feasible alternatives. A one-dimensional which serve computationally inexpensive replacement ease parameter optimisation, analyses quantification. findings be generalised organ-scale models. increase applicability computational regarding treatment development cerebrovascular conditions.

Язык: Английский

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In silico trials for treatment of acute ischemic stroke: Design and implementation

Computers in Biology and Medicine, Год журнала: 2021, Номер 137, С. 104802 - 104802

Опубликована: Авг. 26, 2021

An in silico trial simulates a disease and its corresponding therapies on cohort of virtual patients to support the development evaluation medical devices, drugs, treatment. In trials have potential refine, reduce cost, partially replace current vivo studies, namely clinical animal testing. We present design implementation an for treatment acute ischemic stroke. propose event-based modelling approach simulation injury, where changes state system (the events) are assumed be instantaneous. Using this we able combine diverse set models, spanning multiple time scales, model stroke, treatment, resulting brain tissue injury. The is designed modular aid reproducibility. It provides comprehensive framework application any trial. A statistical population used generate cohorts patients. Patient functional outcomes also predicted with model, using injury results patient's parameters. demonstrate functionality by running proof concept trials. simulate same twice: once successful (successful recanalisation) unsuccessful (unsuccessful treatment). Ways overcome some challenges difficulties setting up such discussed, as validation computational limitations.

Язык: Английский

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Modelling the impact of clot fragmentation on the microcirculation after thrombectomy

PLoS Computational Biology, Год журнала: 2021, Номер 17(3), С. e1008515 - e1008515

Опубликована: Март 12, 2021

Many ischaemic stroke patients who have a mechanical removal of their clot (thrombectomy) do not get reperfusion tissue despite the thrombus being removed. One hypothesis for this ‘no-reperfusion’ phenomenon is micro-emboli fragmenting off large during thrombectomy and occluding smaller blood vessels downstream location. This impossible to observe in-vivo so we here develop an in-silico model based on in-vitro experiments effect brain tissue. Through obtain, under variety consistencies techniques, distributions post-thrombectomy. Blood flow through microcirculation modelled statistically accurate voxels microvasculature including penetrating arterioles capillary beds. A novel algorithm, informed by experimental data, used simulate impact successively entering bed. Scaled-up parameters–permeability coupling coefficients–are calculated various conditions. We find that beds are more susceptible occlusions than with 4x greater drop in permeability per volume vessel occluded. Individual microvascular geometries determine robustness micro-emboli. Hard fragmentation leads larger drops given number Thrombectomy technique has hence microvasculature. As such, modelling predicts specific factors, interventional technique, geometry strongly influence brain. Micro-emboli likely contributory no-reperfusion following successful major clot.

Язык: Английский

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Quantification of hypoxic regions distant from occlusions in cerebral penetrating arteriole trees

PLoS Computational Biology, Год журнала: 2022, Номер 18(8), С. e1010166 - e1010166

Опубликована: Авг. 5, 2022

The microvasculature plays a key role in oxygen transport the mammalian brain. Despite close coupling between cerebral vascular geometry and local demand, recent experiments have reported that microvascular occlusions can lead to unexpected distant tissue hypoxia infarction. To better understand spatial correlation hypoxic regions occlusion sites, we used both vivo silico simulations investigate effects of penetrating arteriole trees on hypoxia. In rat model microembolisation, 25 μm microspheres were injected through carotid artery occlude arterioles. representative models human cortical columns, arterioles occluded by simulating same size was simulated using Green’s function method. locations segmented, two novel distance analyses implemented study their correlation. found be present simulations, mainly due hypoperfusion region downstream site. Furthermore, reasonable agreement for sites is shown which indicates good applicability understanding response blood flow microemboli.

Язык: Английский

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Review of in silico models of cerebral blood flow in health and pathology

Progress in Biomedical Engineering, Год журнала: 2023, Номер 5(2), С. 022003 - 022003

Опубликована: Апрель 1, 2023

Abstract In this review, we provide a summary of the state-of-the-art in silico modelling cerebral blood flow (CBF) and its application clinical trials. CBF plays key role transport nutrients, including oxygen glucose, to brain cells, vasculature is highly complex, multi-scale, dynamic system that acts ensure supply demand these nutrients are continuously balanced. It also other substances, such as recombinant tissue-plasminogen activator, tissue. Any dysfunction can rapidly lead cell death permanent damage regions, leading loss bodily functions death. The complexity difficulty obtaining accurate anatomical information combine make mathematical models understanding supply, diagnosis cerebrovascular disease, quantification effects thrombi, selection optimum intervention, neurosurgical planning. Similar have now been widely applied variety body organs (most notably heart), but still far behind. increased availability experimental data last 15 years however has enabled develop more progress focus review. We thus present brief review foundations underpin both microvasculature macrovasculature. demonstrate how be context diseases show work recently expanded trials for first time. Most date performed ischaemic stroke or aneurysms, in-silico many applications neurodegenerative where vital play testing hypotheses providing test beds interventions.

Язык: Английский

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MRI-based parameter inference for cerebral perfusion modelling in health and ischaemic stroke

Computers in Biology and Medicine, Год журнала: 2023, Номер 166, С. 107543 - 107543

Опубликована: Сен. 30, 2023

Cerebral perfusion modelling is a promising tool to predict the impact of acute ischaemic stroke treatments on spatial distribution cerebral blood flow (CBF) in human brain. To estimate treatment efficacy based CBF, simulations need become suitable for group-level investigations and thus account physiological variability between individuals. However, computational date has been restricted few patient-specific cases. This study set out establish automated parameter inference neuroimaging data enable CBF groups. Magnetic resonance imaging (MRI) from 75 healthy senior adults were utilised. Brain geometries computed reference subjects' T1-weighted MRI. Haemodynamic model parameters determined maps measured by arterial spin labelling (ASL) Thereafter, conducted cases followed 150 representing an occlusion cessation left right middle arteries. The anatomical fitness brain was evaluated comparing simulated grey (GM) white matter (WM) volumes measurements subjects. Strong positive correlations found both tissue types (GM: Pearson's r 0.74, P<0.001; WM: 0.84, P<0.001). tuning verified total volumetric rate subjects (Pearson's 0.89, In cases, infarct volume using perfusion-based 197±25 ml. Computational predictions agreement with haemodynamic values literature concerning T1-weighted, T2-weighted, phase-contrast MRI scenarios did not capture small infarcts (left tail distribution), which could be explained neglected compensatory mechanisms, e.g. collaterals. proposed method provides foundation silico clinical trials assist medical device drug development.

Язык: Английский

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Advancing treatment of retinal disease through in silico trials

Progress in Biomedical Engineering, Год журнала: 2023, Номер 5(2), С. 022002 - 022002

Опубликована: Март 29, 2023

Abstract Treating retinal diseases to prevent sight loss is an increasingly important challenge. Thanks the configuration of eye, retina can be examined relatively easily in situ . Owing recent technological development scanning devices, much progress has been made understanding structure and characterising biomarkers. However, treatment options remain limited are often low efficiency efficacy. In years, concept silico clinical trials (ISCTs) adopted by many pharmaceutical companies optimise accelerate therapeutics. ISCTs rely on use mathematical models based physical biochemical mechanisms underpinning a biological system. With appropriate simplifications assumptions, one generate computer simulations various regimens, new therapeutic molecules, delivery strategies so forth, rapidly at fraction cost required for equivalent experiments. Such have potential not only hasten therapies but also existing this paper, we review state-of-the-art mathematicians, biomedical scientists clinicians, highlighting challenges developing ISCTs. Throughout highlight key findings from about physiology health disease. We describe main building blocks identify diseases.

Язык: Английский

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Linking Vascular Structure and Function: Image-Based Virtual Populations of the Retina

Investigative Ophthalmology & Visual Science, Год журнала: 2024, Номер 65(4), С. 40 - 40

Опубликована: Апрель 29, 2024

This study explored the relationship among microvascular parameters as delineated by optical coherence tomography angiography (OCTA) and retinal perfusion. Here, we introduce a versatile framework to examine interplay between vascular structure function generating virtual vasculatures from central vessels macular capillaries. Also, have developed hemodynamics model that evaluates associations morphology

Язык: Английский

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