Leatherbacks Swimming In Silico: Modeling and Verifying Their Momentum and Heat Balance Using Computational Fluid Dynamics

In silico study of the relationships between flow conditions, arterial surface shear stress, and pressure was investigated in a patient with pulmonary arterial hypertension (PAH), using multi-detector Computed Tomography Angiography (CTA) images and Computational Fluid Dynamics (CFD). The CTA images were converted into 3D models and transferred to CFD software for simulations, allowing for patient-specific comparisons between in silico results with clinical right heart catheterization pressure data. The simulations were performed using two different methods of outlet boundary conditions: zero traction and lumped parameter model (LPM) methods. Outlet pressures were set to a constant value in zero traction method, which can produce flow characteristics solely based on the segmented distal arteries, while the lumped parameter model used a three-element Windkessel lumped model to represent the distal vasculature by accounting for resistance, compliance, and impedance of the vasculature. Considering existing limitations with both approaches, it was found that the lumped parameter Windkessel outlet boundary condition provides a better correlation with the clinical RHC pressure results than the zero traction constant pressure outlet boundary condition.

Download Full-text

Computational Fluid Dynamics Analysis of Early Embryonic Aortic Arch-Ligation

Volume 1A: Abdominal Aortic Aneurysms; Active and Reactive Soft Matter; Atherosclerosis; BioFluid Mechanics; Education; Biotransport Phenomena; Bone, Joint and Spine Mechanics; Brain Injury; Cardiac Mechanics; Cardiovascular Devices, Fluids and Imaging; Cartilage and Disc Mechanics; Cell and Tissue Engineering; Cerebral Aneurysms; Computational Biofluid Dynamics; Device Design, Human Dynamics, and Rehabilitation; Drug Delivery and Disease Treatment; Engineered Cellular Environments ◽

10.1115/sbc2013-14470 ◽

2013 ◽

Author(s):

Prahlad G. Menon ◽

William Kowalski ◽

Kerem Pekkan

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

In Silico ◽

Great Artery ◽

Short Term ◽

Vascular Morphogenesis ◽

Computational Fluid Dynamics Analysis ◽

The Us ◽

Computational Fluid Dynamics Cfd ◽

Biomechanical Forces

Congenital heart disease occurs in 8 out of every 1000 live births in the US and more than half of this population is associated with great artery lesions. Selective remodeling of the paired, bilaterally symmetric embryonic aortic arches (AA) is a crucial stage in vascular morphogenesis and has known association with biomechanical forces [1]. Fetal cardiac interventions are currently explored clinically as an alternative repair technique for congenital anomalies, in-utero [2]. Several computational fluid dynamics (CFD) studies have been performed focusing on subject specific embryonic cardiovascular anatomies [3–5]. These developments could benefit fetal interventions that are planned in-silico before execution. To demonstrate this possibility, we computed the hemodynamic variation and wall shear stress (WSS) patterns resulting from systematic in-silico AA ligation intervention performed on normal chick AA models viz. Hamburger Hamilton (HH) stage 18 and 24 (3 and 4 days, respectively). A unique methodology employing CFD-computed WSS for modeling short-term biological growth response on AA morphogenesis is also presented.

Download Full-text

Human In Silico Trials for Parametric Computational Fluid Dynamics Investigation of Cerebrospinal Fluid Drug Delivery: Impact of Injection Location, Injection Protocol, and Physiology

10.21203/rs.3.rs-1050794/v1 ◽

2021 ◽

Author(s):

Mohammadreza Khani ◽

Goutham Kumar Reddy Burla ◽

Lucas R. Sass ◽

Ostin N. Arters ◽

Tao Xing ◽

...

Keyword(s):

Fluid Dynamics ◽

Drug Delivery ◽

Computational Fluid Dynamics ◽

Stroke Volume ◽

In Silico ◽

Therapeutic Dose ◽

Maximum Concentration ◽

Brain Regions ◽

The Brain ◽

Injection Location

Abstract BackgroundIntrathecal drug delivery has a significant role in pain management and CNS disease therapeutics. A fluid-physics based tool to assist clinicians in choosing specific drug doses to the spine or brain may help improve treatment schedules. MethodsThis study applied computational fluid dynamics (CFD) and in vitro model verification to assess intrathecal drug delivery in an anatomically realistic model of the human CSF system. Key parameters analyzed included the role of a) injection location including lumbar puncture (LP), cisterna magna (CM) and intracerebroventricular (ICV), b) LP injection rate, injection volume, and flush volume, c) physiologic factors including cardiac-induced and deep respiration-induced CSF stroke volume increase. Simulations were conducted for 3-hours post-injection and used to quantify spatial-temporal tracer concentration, regional area under the curve (AUC), time to maximum concentration (T max ), and maximum concentration (C max ), for each case. ResultsCM and ICV increased AUC to brain regions by ~2 logs compared to all other simulations. A 3X increase in bolus volume and addition of a 5 mL flush both increased intracranial AUC to the brain up to 2X compared to a baseline 5 mL LP injection. In contrast, a 5X increase in bolus rate (25 mL/min) did not improve tracer exposure to the brain. An increase in cardiac and respiratory CSF movement improved tracer spread to the brain, basal cistern, and cerebellum up to ~2 logs compared to the baseline LP injection. ConclusionThe computational modeling approach provides ability to conduct in silico trials representative of CSF injection protocols. Taken together, the findings indicate a strong potential for delivery protocols to be optimized to reach a target region(s) of the spine and/or brain with a needed therapeutic dose. Parametric modification of bolus rate/volume and flush volume was found to have impact on tracer distribution; albeit to a smaller degree than injection location, with CM and ICV injections resulting in greater therapeutic dose to brain regions compared to LP. CSF stroke volume and frequency both played an important role and may potentially have a greater impact than the modest changes in LP injection protocols analyzed such as bolus rate, volume, and flush.

Download Full-text

In vitro and in silico (IVIS) flow characterization in an idealized human airway geometry using laser Doppler anemometry and computational fluid dynamics techniques

Measurement ◽

10.1016/j.measurement.2016.04.063 ◽

2016 ◽

Vol 90 ◽

pp. 144-150 ◽

Cited By ~ 11

Author(s):

Attila Kerekes ◽

Attila Nagy ◽

Miklós Veres ◽

István Rigó ◽

Árpád Farkas ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

In Silico ◽

Laser Doppler Anemometry ◽

Laser Doppler ◽

Human Airway ◽

Flow Characterization

Download Full-text

In silico investigation of sneezing in a full real human upper airway using computational fluid dynamics method

Computer Methods and Programs in Biomedicine ◽

10.1016/j.cmpb.2019.05.031 ◽

2019 ◽

Vol 177 ◽

pp. 203-209 ◽

Cited By ~ 7

Author(s):

Hamidreza Mortazavy beni ◽

Kamran Hassani ◽

Siamak Khorramymehr

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

In Silico ◽

Upper Airway ◽

Dynamics Method

Download Full-text

Development of a Computational Fluid Dynamics Model for Myocardial Bridging

Journal of Biomechanical Engineering ◽

10.1115/1.4040127 ◽

2018 ◽

Vol 140 (9) ◽

Cited By ~ 2

Author(s):

Ashkan Javadzadegan ◽

Abouzar Moshfegh ◽

David Fulker ◽

Tracie Barber ◽

Yi Qian ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Shear Stress ◽

In Silico ◽

Moving Boundary ◽

Proximal Segment ◽

Cfd Modeling ◽

Patient Specific ◽

Myocardial Bridging ◽

In Silico Model

Computational fluid dynamics (CFD) modeling of myocardial bridging (MB) remains challenging due to its dynamic and phasic nature. This study aims to develop a patient-specific CFD model of MB. There were two parts to this study. The first part consisted of developing an in silico model of the left anterior descending (LAD) coronary artery of a patient with MB. In this regard, a moving-boundary CFD algorithm was developed to simulate the patient-specific muscle compression caused by MB. A second simulation was also performed with the bridge artificially removed to determine the hemodynamics in the same vessel in the absence of MB. The second part of the study consisted of hemodynamic analysis of three patients with mild and moderate and severe MB in their LAD by means of the developed in silico model in the first part. The average shear stress in the proximal and bridge segments for model with MB were significantly different from those for model without MB (proximal segment: 0.32 ± 0.14 Pa (with MB) versus 0.97 ± 0.39 Pa (without MB), P < 0.0001 — bridge segment: 2.60 ± 0.94 Pa (with MB) versus 1.50 ± 0.64 Pa (without MB), P < 0.0001). When all three patients were evaluated, increasing the degree of vessel compression shear stress in the proximal segment decreased, whereas the shear stress in the bridge segment increased. The presence of MB resulted in hemodynamic abnormalities in the proximal segment, whereas segments within the bridge exhibited hemodynamic patterns which tend to discourage atheroma development.

Download Full-text