Non-newtonian Blood Flow Analysis for the Portal Vein Based on a CT Image

Ho, Harvey; Bartlett, Adam; Hunter, Peter

doi:10.1007/978-3-642-33612-6_30

Cited by 5 publications

(4 citation statements)

References 8 publications

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“…In the computational model, blood was modeled as an incompressible non-Newtonian fluid and blood flow was governed by the continuity and Navier–Stokes equations. The non-Newtonian rheology of blood was herein considered because blood flows slowly in the portal venous system, especially after splenectomy, and under such conditions, the shear-rate-dependent change in blood viscosity would become evident ( Ho et al, 2012 ). In this study, the Carreau model was employed to represent the change in blood viscosity with shear rate ( Johnston et al, 2004 ).…”

Section: Methodsmentioning

confidence: 99%

“…The portal venous walls were assumed to be rigid, to which the no-slip boundary condition was imposed.In the computational model, blood was modeled as an incompressible non-Newtonian fluid and blood flow was governed by the continuity and Navier-Stokes equations. The non-Newtonian rheology of blood was herein considered because blood flows slowly in the portal venous system, especially after splenectomy, and under such conditions, the shear-rate-dependent change in blood viscosity would become evident(Ho et al, 2012). In…”

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confidence: 99%

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A computational model-based study on the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics

Wang,

Yong,

et al. 2024

Front. Bioeng. Biotechnol.

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For portal hypertensive patients with splenomegaly and hypersplenism, splenectomy is an effective surgery to relieve the complications. However, patients who have undergone splenectomy often suffer from portal venous system thrombosis, a sequela that requires prophylaxis and timely treatment to avoid deterioration and death. The aim of this study is to investigate the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics based on computational models. First, 15 portal hypertensive patients who had undergone splenectomy were enrolled, and their preoperative clinical data and postoperative follow-up results were collected. Next, computational models of the portal venous system were constructed based on the preoperative computed tomography angiography images and ultrasound-measured flow velocities. On this basis, splenectomy was mimicked and the postoperative area of low wall shear stress (ALWSS) was simulated for each patient-specific model. Finally, model-simulated ALWSS was statistically compared with the patient follow-up results to investigate the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics. Results showed that ALWSS could predict the occurrence of post-splenectomy thrombosis with the area under the receiver operating characteristic curve (AUC) equal to 0.75. Moreover, statistical analysis implied that the diameter of the splenic vein is positively correlated with ALWSS (r = 0.883, p < 0.0001), and the anatomical structures of the portal venous system also influence the ALWSS. These findings demonstrated that the computational model-based hemodynamic metric ALWSS, which is associated with the anatomorphological features of the portal venous system, is capable of predicting the occurrence of post-splenectomy thrombosis, promoting better prophylaxis and postoperative management for portal hypertensive patients receiving splenectomy.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

A computational model-based study on the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics

Wang,

Yong,

et al. 2024

Front. Bioeng. Biotechnol.

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“…Parallel finite element methods based on domain decomposition method for the Navier–Stokes equations have been proposed in which the computation is run on thousands of processors to shorten the computation time (Lin et al, 2021). Despite the computational cost, 3D simulations are used to reveal flow patterns such as wall shear stress (WSS) distribution, helical flow, and re‐circulation zones, which are otherwise infeasible to evaluate from flow models of lower dimensions (George et al, 2015; Ho et al, 2012; Lin et al, 2021). For instance, 3D blood flow features are valuable in simulating the accumulation of deposits in intrahepatic grafts such as the Trans‐jugular Intrahepatic Portosystemic Shunt (TIPS), and to evaluate the restenosis risk (Perarnau et al, 2014).…”

Section: Hepatic Circulation Models At the Organ Levelmentioning

confidence: 99%

In silico modeling for the hepatic circulation and transport: From the liver organ to lobules

Means

Safaei

et al. 2022

WIREs Mechanisms of Disease

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The function of the liver depends critically on its blood supply. Numerous in silico models have been developed to study various aspects of the hepatic circulation, including not only the macro-hemodynamics at the organ level, but also the microcirculation at the lobular level. In addition, computational models of blood flow and bile flow have been used to study the transport, metabolism, and clearance of drugs in pharmacokinetic studies.These in silico models aim to provide insights into the liver organ function under both healthy and diseased states, and to assist quantitative analysis for surgical planning and postsurgery treatment. The purpose of this review is to provide an update on state-of-the-art in silico models of the hepatic circulation and transport processes. We introduce the numerical methods and the physiological background of these models. We also discuss multiscale frameworks that have been proposed for the liver, and their linkage with the large context of systems biology, systems pharmacology, and the Physiome project.

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“…Venous blood was modeled as an incompressible non-Newtonian fluid with a density of 1,060 kg/mł, and blood flow was governed by the continuity and Navier-Stokes equations. Herein, the non-Newtonian rheology of blood was considered since blood flow in the PVS is slow, making the shear-rate dependent effect of blood viscosity more evident than in large arteries where blood flow velocities are much higher (Ho et al, 2012). In this study, the Carreau model was employed to represent the change in blood viscosity (µ) with shear rate (…”

Section: Mesh Generation and Setup Of Hemodynamic Modelmentioning

confidence: 99%

Influences of Anatomorphological Features of the Portal Venous System on Postsplenectomy Hemodynamic Characteristics in Patients With Portal Hypertension: A Computational Model-Based Study

2021

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Splenectomy, as an effective surgery for relieving complications caused by portal hypertension, is often accompanied by a significantly increased incidence of postoperative thrombosis in the portal venous system (PVS). While the underlying mechanisms remain insufficiently understood, the marked changes in hemodynamic conditions in the PVS following splenectomy have been suggested to be a potential contributing factor. The aim of this study was to investigate the influences of the anatomorphological features of the PVS on hemodynamic characteristics before and after splenectomy, with emphasis on identifying the specific anatomorphological features that make postoperative hemodynamic conditions more clot-promoting. For this purpose, idealized computational hemodynamics models of the PVS were constructed based on general anatomical structures and population-averaged geometrical parameters of the PVS. In the models, we incorporated various anatomorphological variations to represent inter-patient variability. The analyses of hemodynamic data were focused on the spatial distribution of wall shear stress (WSS) and the area ratio of wall regions exposed to low WSS (ALS). Obtained results showed that preoperative hemodynamic conditions were comparable among different models in terms of space-averaged WSS and ALS (all were small) irrespective of the considerable differences in spatial distribution of WSS, whereas, the inter-model differences in ALS were significantly augmented after splenectomy, with the value of ALS reaching up to over 30% in some models, while being smaller than 15% in some other models. Postoperative ALS was mainly determined by the anatomical structure of the PVS, followed by some morphogeometrical parameters, such as the diameter and curvature of the splenic vein, and the distance between the inferior mesenteric vein and splenoportal junction. Relatively, the angles between tributary veins and trunk veins only had mild influences on ALS. In addition, a marked increase in blood viscosity was predicted after splenectomy, especially in regions with low WSS, which may play an additive role to low WSS in initiating thrombosis. These findings suggest that the anatomical structure and some morphogeometrical features of the PVS are important determinants of hemodynamic conditions following splenectomy, which may provide useful clues to assessing the risk of postsplenectomy thrombosis based on medical imaging data.

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Non-newtonian Blood Flow Analysis for the Portal Vein Based on a CT Image

Cited by 5 publications

References 8 publications

A computational model-based study on the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics

A computational model-based study on the feasibility of predicting post-splenectomy thrombosis using hemodynamic metrics

In silico modeling for the hepatic circulation and transport: From the liver organ to lobules

Influences of Anatomorphological Features of the Portal Venous System on Postsplenectomy Hemodynamic Characteristics in Patients With Portal Hypertension: A Computational Model-Based Study

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