scholarly journals Efficient finite element hyperelasticity solver for blood vessel simulations

2020 ◽  
Vol 14 ◽  
pp. 174830262093101
Author(s):  
Xinhong Wang ◽  
Zhengzheng Yan ◽  
Yi Jiang ◽  
Rongliang Chen
Keyword(s):  
Finite Element ◽  
Blood Vessel ◽  
Blood Vessels ◽  
High Performance ◽  
Soft Tissues ◽  
Circulatory System ◽  
Numerical Algorithms ◽  
External Pressure ◽  
Patient Specific ◽  
Schwarz Method

The blood vessels play a key role in the human circulatory system. As a tremendous amount of efforts have been devoted to develop mathematical models for investigating the elastic behaviors of human blood vessels, high performance numerical algorithms aiming at solving these models have attracted attention. In this work, we present an efficient finite element solver for an elastodynamic model which is commonly used for simulating soft tissues under external pressure loadings. In particular, the elastic material is assumed to satisfy the Saint–Venant–Kirchhoff law, the governing equation is spatially discretized by a finite element method, and a fully implicit backward difference method is used for the temporal discretization. The resulting nonlinear system is then solved by a Newton–Krylov–Schwarz method. It is the first time to apply the Newton–Krylov–Schwarz method to the Saint–Venant–Kirchhoff model for a patient-specific blood vessel. Numerical tests verify the efficiency of the proposed method and demonstrate its capability for bioengineering applications.

scholarly journals Maladaptive neuropathological syndrome of blood vessel aging

2019 ◽  
pp. 33-40
Author(s):  
A. A. Artemenkov
Keyword(s):  
Cerebral Cortex ◽  
Blood Vessel ◽  
Blood Vessels ◽  
Cortical Neurons ◽  
Circulatory System ◽  
Vascular Wall ◽  
Modern Human ◽  
Wall Thickening ◽  
Additional Risk Factor ◽  
The Relationship

This article discusses the relationship between maladaptation and blood vessel aging. The work shows that upright posture created an additional load on the circulatory system, and the lifestyle of a modern human is an additional risk factor of cardiovascular diseases. It has been suggested that a disorder of the nervous regulation of vascular tone is the main etiopathogenetic mechanism of morphofunctional changes in blood vessels and their aging. We discussed the statute that vascular reactions in humans is based on the formation of a maladaptive circuit in the cerebral cortex, consisting of a matrix of motor, sensory and associative cortical neurons involved in the maladaptive process. This hypothesis is based on the fact that any irritations entering the cerebral cortex from the periphery (thermal, pain, and others) cause cortical-vascular reflex reactions that change their tonic activity. Based on this principle, a model of vascular aging is further constructed, which is based on the maladaptive damage to all layers of the vascular wall (intima, media and adventitia). The opinion is expressed about the need for early diagnosis and prevention of vascular disorders to maintain human health. In conclusion, it is concluded that if the age of a person is really determined by the age of his blood vessels, then in order to achieve active longevity it is necessary to normalize the relationship in the adaptation-maladaptation-environment. Detailed study of hypertrophy and calcification of blood vessels is needed, since aging always reveals vascular wall thickening and stiffness increase.

scholarly journals Quantitative Assessment of 3D Printed Blood Vessels Produced with J750™ Digital Anatomy™ for Suture Simulation

2022 ◽  
Author(s):  
Stefania Marconi ◽  
Valeria Mauri ◽  
Erika Negrello ◽  
Luigi Pugliese ◽  
Andrea Pietrabissa ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Soft Tissues ◽  
Surgical Simulation ◽  
Patient Specific ◽  
Morphological Aspects ◽  
Pathological Conditions ◽  
Surgical Simulations ◽  
Training Of Surgeons ◽  
3D Printed ◽  
Digital Anatomy

Blood vessels anastomosis is one of the most challenging and delicate tasks to learn in many surgical specialties, especially for vascular and abdominal surgeons. Such a critical skill implies a learning curve that goes beyond technical execution. The surgeon needs to gain proficiency in adapting gestures and the amount of force expressed according to the type of tissue he/she is dealing with. In this context, surgical simulation is gaining a pivotal role in the training of surgeons, but currently available simulators can provide only standard or simplified anatomies, without the chance of presenting specific pathological conditions and rare cases. 3D printing technology, allowing the manufacturing of extremely complex geometries, find a perfect application in the production of realistic replica of patient-specific anatomies. According to available technologies and materials, morphological aspects can be easily handled, while the reproduction of tissues mechanical properties still poses major problems, especially when dealing with soft tissues. The present work focuses on blood vessels, with the aim of identifying – by means of both qualitative and quantitative tests – materials combinations able to best mimic the behavior of the biological tissue during anastomoses, by means of J750™ Digital Anatomy™ technology and commercial photopolymers from Stratasys. Puncture tests and stitch traction tests are used to quantify the performance of the various formulations. Surgical simulations involving anastomoses are performed on selected clinical cases by surgeons to validate the results. A total of 37 experimental materials were tested and 2 formulations were identified as the most promising solutions to be used for anastomoses simulation. Clinical applicative tests, specifically selected to challenge the new materials, raised additional issues on the performance of the materials to be considered for future developments.

Study of Sushrutokta Vedhya Sira of Urdhavshakha In Siravedhan Vidhi

2019 ◽  
Vol 7 (02) ◽  
Author(s):  
Sachin S. Bhagwat
Keyword(s):  
Blood Vessel ◽  
Blood Vessels ◽  
Circulatory System ◽  
Upper Extremities ◽  
Anatomical Structures ◽  
Contemporary Science

The term “Sira” is collectively used for blood vessel ( Arteries, Veins, Capillaries and Lymphatics ) which denote the circulatory system. Some siras are not suitable for venouspuncture. These siras are called Avedhya Sira. A surgeon should not perform venesection on these sira as it may be harmful for patient; on the contrary, some sira are suitable for Siravedhan, called Vedhya Sira. The anatomical locations are available in classic texts but exact structures and the anatomical description regarding vedhya sira are not described yet. Proposed article aims to correlate urdhvashakhagat vedhya siras mentioned by our Aacharya with modern anatomical structures and review in contemporary science. For this purpose, ancient ayurvedic classics were reviewed and references are compiled for the said subject was criticaly studied to comprehend the vedhya sira in upper extremities. Primary knowledge of vedhya Sira is very important for physicians as well as surgeons. The vedhya sira mentioned in Ayurved compendia can be correlated with blood vessels, vein in modern anatomy.

The Effects of Blood Flow on Blood Vessel Buckling Embedded in Surrounding Soft Tissues

2016 ◽  
Vol 08 (05) ◽  
pp. 1650065 ◽  
Author(s):  
M. Hosseini ◽  
M. A. Paparisabet
Keyword(s):  
Blood Flow ◽  
Blood Vessel ◽  
Blood Cell ◽  
Flow Velocity ◽  
Blood Vessels ◽  
Red Blood Cell ◽  
Blood Flow Velocity ◽  
Soft Tissues ◽  
Flexible Beam ◽  
Critical Buckling Pressure

When blood flows in vessel curved portion, the presence of curvature generates a centrifugal force that acts in the same manner as a compressive load. Therefore, blood flow velocity has an important effect on the stability of vessels. In this study, the blood vessel is simulated as a flexible beam conveying fluid base on Euler–Bernoulli beam theory, and various boundary conditions are represented for the modeled vessels. Then, analytical and numerical methods are deployed to extract desired parameters. The effects of blood flow, hematocrit and stiffness of surrounding tissues on the buckling critical pressure are investigated. The results show that the mentioned parameters have considerable effects on blood vessels stability. Several numerical findings illustrate a reduction in critical buckling pressure with increasing hematocrit and blood flow velocity. In addition, the size of red blood cell has a significant effect on critical buckling pressure in low hematocrits. As increasing red blood cell diameter decreases critical buckling pressure. Furthermore, because of blood viscosity, the non-uniformity effects of the blood flow on blood vessels stability are investigated by considering a modification factor. These results improve our understanding of blood vessels instability.

Geometric Standardization and Luminal Lubrication of Silicone Vascular Model for Neuroendovascular Simulation

2009 ◽  
Author(s):  
Juyu Chueh ◽  
Matthew J. Gounis
Keyword(s):  
Standard Model ◽  
Blood Vessel ◽  
Blood Vessels ◽  
Medical Devices ◽  
Entire Population ◽  
Patient Specific ◽  
Branch Angle ◽  
Vascular Geometry ◽  
Universal Definition ◽  
Curvature Information

Artificial cerebrovascular replicas present realistic vascular geometry and have versatile applications in the development and testing of medical devices. Different methods for construction of patient specific silicone vascular models have been proposed previously; however, due to the variations in the cerebrovascular anatomy, results obtained from these models may not be generalized to the entire population. To prepare a geometrically standard model, vessel characterization is necessary. Common attributes measured to quantitatively describe blood vessels include diameter, length, branch angle, and tortuosity, and among them, tortuosity evaluation is widely discussed. To date, tortuosity lacks a universal definition, but is generally used to summarize curvature information along the centerline of a blood vessel.

scholarly journals Patient-specific finite element model of the hip muscles and bones

2009 ◽  
pp. 117-129
Author(s):  
Erwan Jolivet ◽  
Jean-Denis Laredo ◽  
Dominique Bonneau ◽  
Wafa Skalli
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Model ◽  
Constitutive Equations ◽  
Soft Tissues ◽  
Element Model ◽  
Patient Specific ◽  
Major Health ◽  
Distorted Mesh ◽  
Hip Muscles

Hip fractures are largely considered as a major health-care problem. Several patientspecific finite element models of the isolated femur are proposed to evaluate fracture risk. However, because of their role in femur stress distribution, soft tissue covering the hip should also be considered. Such modeling is particularly complex and major difficulties are related to volumic muscle mesh generation, to specific muscles constitutive equations and numerous contacts within the structure. A method was based on deformation of a parameterized muscle mesh was proposed to get rapidly a patient-specific non distorted mesh. Based in this mesh, finite element model included bones and soft tissues, with surface contact elements between components. Hyperelastic constitutive equations, with hypothesis of incompressibility and isotropy were used to model soft tissue mechanical behavior. Preliminary simulation with quasistatic lateral compression was performed to verify the coherence of the model’s response.

PATIENT-SPECIFIC FINITE ELEMENT MODEL OF THE HIP INCLUDING SOFT TISSUES

2008 ◽  
Vol 41 ◽  
pp. S370 ◽  
Author(s):  
Erwan Jolivet ◽  
Jean-Denis Laredo ◽  
Wafa Skalli
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Soft Tissues ◽  
Element Model ◽  
Patient Specific

COMPARISON OF ANTIHYPERTENSIVE EFFECT OF MOXONIDINE VERSUS CLONIDINE IN RENAL FAILURE PATIENTS.

2018 ◽  
Vol 6 (9) ◽  
Author(s):  
DR.MATHEW GEORGE ◽  
DR.LINCY JOSEPH ◽  
MRS.DEEPTHI MATHEW ◽  
ALISHA MARIA SHAJI ◽  
BIJI JOSEPH ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Failure ◽  
Blood Flow ◽  
Blood Vessel ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Antihypertensive Effect ◽  
The Body ◽  
Ability To Work ◽  
Blood Flows

Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body. Factors that can increase this force include higher blood volume due to extra fluid in the blood and blood vessels that are narrow, stiff, or clogged(1). High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.

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