Validation of 1D Model of the Systemic Arterial Tree Including the Cerebral Circulation

2008 ◽  
Author(s):  
Philippe Reymond ◽  
Fabrice Merenda ◽  
Fabienne Perren ◽  
Daniel Rüfenacht ◽  
Nikos Stergiopulos
Keyword(s):  
Cerebral Circulation ◽  
Cerebral Arteries ◽  
Distributed Model ◽  
Heart Model ◽  
Arterial Tree ◽  
Distributed Models ◽  
The Past ◽  
1D Model ◽  
Systemic Arterial Tree

The aim of this study is to develop a distributed model of the entire systemic arterial tree, coupled to a heart model and including a detailed description of the cerebral arteries. Distributed models of the arterial tree have been studied extensively in the past (Avolio [1], Stergiopulos et al [2], Westerhof et al [3]), however, no model has been developed so far that offers a physiologically relevant coupling to the heart and includes the entire cerebral arterial tree.

One Dimensional Model of the Systemic Arterial Tree Including Cerebral Circulation

2007 ◽  
Author(s):  
Philippe Reymond ◽  
Fabrice Merenda ◽  
Fabienne Perren ◽  
Daniel Rüfenacht ◽  
Nikos Stergiopulos
Keyword(s):  
Cerebral Circulation ◽  
Cerebral Arteries ◽  
Distributed Model ◽  
Dimensional Model ◽  
Heart Model ◽  
Arterial Tree ◽  
One Dimensional ◽  
Distributed Models ◽  
The Past ◽  
Systemic Arterial Tree

The aim of this study is to develop a distributed model of the entire systemic arterial tree, coupled to a heart model and including a detailed description of the cerebral arteries. Distributed models of the arterial tree have been studied extensively in the past (Avolio [1]; Cassot et al [2]; Meister [3]; Schaaf and Abbrecht [4]; Stergiopulos et al [5]; Westerhof et al [6]; Zagzoule and Marc-Vergnes [7]), however, no model has been developed so far that offers a physiologically relevant coupling to the heart and includes the entire cerebral artery network.

VALIDATION OF 1D MODEL OF THE SYSTEMIC ARTERIAL TREE INCLUDING THE CEREBRAL CIRCULATION

2008 ◽  
Vol 41 ◽  
pp. S296
Author(s):  
Philippe Reymond ◽  
Fabrice Merenda ◽  
Fabienne Perren ◽  
Daniel Rüfenacht ◽  
Nikos Stergiopulos
Keyword(s):  
Cerebral Circulation ◽  
Arterial Tree ◽  
1D Model ◽  
Systemic Arterial Tree

03.03 VALIDATION OF A 1D MODEL OF THE SYSTEMIC ARTERIAL TREE INCLUDING THE CEREBRAL CIRCULATION

2008 ◽  
Vol 2 (3) ◽  
pp. 87
Author(s):  
P.G. Reymond ◽  
F. Perren ◽  
D.A. Rüfenacht ◽  
N. Stergiopulos
Keyword(s):  
Cerebral Circulation ◽  
Arterial Tree ◽  
1D Model ◽  
Systemic Arterial Tree

Validation of a Person Specific 1D Model of the Systemic Arterial Tree

2009 ◽  
Author(s):  
Philippe Reymond ◽  
Yvette Bohraus ◽  
Fabienne Perren ◽  
Nikos Stergiopulos
Keyword(s):  
Elastic Tube ◽  
Distributed Model ◽  
Physiological Data ◽  
Arterial Tree ◽  
Non Invasive ◽  
1D Model ◽  
Quantitative Validation ◽  
Systemic Arterial Tree

The aim of this study is to validate a person-specific distributed model of the main systemic arterial tree. This model is built and validated with non-invasive measurements on the same person, leading therefore to a coherent set of physiological data. One-dimensional (1D) models have been used for more than 30 years to predict or analyze pressure and flow in the arterial tree (Avolio [1], Stergiopulos et al [2], Westerhof et al [3]), demonstrating their aptitude of modeling wave propagation, however, they have never being validated using in vivo measurements. A quantitative validation was performed in vitro in an elastic tube network dimensioned to resemble the human arterial tree by Matthys et al. [4]. The results were supportive of the 1D model’s capacity to yield good predictions, however, neither the form of the waves nor the elastic properties of the in vitro tube network were matching faithfully their physiological counterparts, so the interest to quantitatively validate the 1D model in vivo remained.

scholarly journals Validation of a one-dimensional model of the systemic arterial tree

2009 ◽  
Vol 297 (1) ◽  
pp. H208-H222 ◽  
Author(s):  
Philippe Reymond ◽  
Fabrice Merenda ◽  
Fabienne Perren ◽  
Daniel Rüfenacht ◽  
Nikos Stergiopulos
Keyword(s):  
Constitutive Law ◽  
Distributed Model ◽  
Arterial Tree ◽  
One Dimensional ◽  
Continuity Equations ◽  
Nonlinear Viscoelastic ◽  
Model Predictions ◽  
The One ◽  
D Model ◽  
Systemic Arterial Tree

A distributed model of the human arterial tree including all main systemic arteries coupled to a heart model is developed. The one-dimensional (1-D) form of the momentum and continuity equations is solved numerically to obtain pressures and flows throughout the systemic arterial tree. Intimal shear is modeled using the Witzig-Womersley theory. A nonlinear viscoelastic constitutive law for the arterial wall is considered. The left ventricle is modeled using the varying elastance model. Distal vessels are terminated with three-element windkessels. Coronaries are modeled assuming a systolic flow impediment proportional to ventricular varying elastance. Arterial dimensions were taken from previous 1-D models and were extended to include a detailed description of cerebral vasculature. Elastic properties were taken from the literature. To validate model predictions, noninvasive measurements of pressure and flow were performed in young volunteers. Flow in large arteries was measured with MRI, cerebral flow with ultrasound Doppler, and pressure with tonometry. The resulting 1-D model is the most complete, because it encompasses all major segments of the arterial tree, accounts for ventricular-vascular interaction, and includes an improved description of shear stress and wall viscoelasticity. Model predictions at different arterial locations compared well with measured flow and pressure waves at the same anatomical points, reflecting the agreement in the general characteristics of the “generic 1-D model” and the “average subject” of our volunteer population. The study constitutes a first validation of the complete 1-D model using human pressure and flow data and supports the applicability of the 1-D model in the human circulation.

Validation of a patient-specific one-dimensional model of the systemic arterial tree

2011 ◽  
Vol 301 (3) ◽  
pp. H1173-H1182 ◽  
Author(s):  
Philippe Reymond ◽  
Yvette Bohraus ◽  
Fabienne Perren ◽  
Francois Lazeyras ◽  
Nikos Stergiopulos
Keyword(s):  
Arterial Wall ◽  
Specific Model ◽  
Constitutive Law ◽  
Distributed Model ◽  
Patient Specific ◽  
Dimensional Model ◽  
Arterial Tree ◽  
One Dimensional ◽  
Flow Waveforms ◽  
Systemic Arterial Tree

The aim of this study is to develop and validate a patient-specific distributed model of the systemic arterial tree. This model is built using geometric and hemodynamic data measured on a specific person and validated with noninvasive measurements of flow and pressure on the same person, providing thus a patient-specific model and validation. The systemic arterial tree geometry was obtained from MR angiographic measurements. A nonlinear viscoelastic constitutive law for the arterial wall is considered. Arterial wall distensibility is based on literature data and adapted to match the wave propagation velocity of the main arteries of the specific subject, which were estimated by pressure waves traveling time. The intimal shear stress is modeled using the Witzig-Womersley theory. Blood pressure is measured using applanation tonometry and flow rate using transcranial ultrasound and phase-contrast-MRI. The model predicts pressure and flow waveforms in good qualitative and quantitative agreement with the in vivo measurements, in terms of wave shape and specific wave features. Comparison with a generic one-dimensional model shows that the patient-specific model better predicts pressure and flow at specific arterial sites. These results obtained let us conclude that a patient-specific one-dimensional model of the arterial tree is able to predict well pressure and flow waveforms in the main systemic circulation, whereas this is not always the case for a generic one-dimensional model.

Abnormal arterial flows by a distributed model of the fetal circulation

2006 ◽  
Vol 291 (5) ◽  
pp. R1222-R1233 ◽  
Author(s):  
Jeroen P. H. M. van den Wijngaard ◽  
Berend E. Westerhof ◽  
Dirk J. Faber ◽  
Margaret M. Ramsay ◽  
Nico Westerhof ◽  
...  
Keyword(s):  
Blood Viscosity ◽  
Arterial Wall ◽  
Cerebral Arteries ◽  
Arterial Flow ◽  
Distributed Model ◽  
Rheological Parameters ◽  
Arterial Tree ◽  
Arterial Circulation ◽  
Wide Range ◽  
Resistance Decrease

Modeling the propagation of blood pressure and flow along the fetoplacental arterial tree may improve interpretation of abnormal flow velocity waveforms in fetuses. The current models, however, either do not include a wide range of gestational ages or do not account for variation in anatomical, vascular, or rheological parameters. We developed a mathematical model of the pulsating fetoumbilical arterial circulation using Womersley's oscillatory flow theory and viscoelastic arterial wall properties. Arterial flow waves are calculated at different arterial locations from which the pulsatility index (PI) can be determined. We varied blood viscosity, placental and brain resistances, placental compliance, heart rate, stiffness of the arterial wall, and length of the umbilical arteries. The PI increases in the umbilical artery and decreases in the cerebral arteries, as a result of increasing placental resistance or decreasing brain resistance. Both changes in resistance decrease the flow through the placenta. An increased arterial stiffness increases the PIs in the entire fetoplacental circulation. Blood viscosity and peripheral bed compliance have limited influence on the flow profiles. Bradycardia and tachycardia increase and decrease the PI in all arteries, respectively. Umbilical arterial length has limited influence on the PI but affects the mean arterial pressure at the placental cord insertion. The model may improve the interpretation of arterial flow pulsations and thus may advance both the understanding of pathophysiological processes and clinical management.

Distributed Modeling Of Building Systems Through Cyber-Physical Integration

2019 ◽  
pp. 12-17
Keyword(s):  
Data Structure ◽  
Operating Conditions ◽  
Physical Models ◽  
Distributed Model ◽  
Physical Processes ◽  
Distributed Modeling ◽  
Distributed Models ◽  
Operating Modes ◽  
Building Systems ◽  
Important Practical Application

This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.

NUMERICAL SIMULATION AND VALIDITY OF A NOVEL METHOD FOR THE PREDICTION OF ARTERY STENOSIS VIA INPUT IMPEDANCE AND SUPPORT VECTOR MACHINE

2014 ◽  
Vol 26 (01) ◽  
pp. 1450002 ◽  
Author(s):  
Hanguang Xiao
Keyword(s):  
Support Vector Machine ◽  
Input Impedance ◽  
Recursive Algorithm ◽  
Artery Stenosis ◽  
Support Vector ◽  
Arterial Tree ◽  
Novel Method ◽  
The Mean ◽  
Fold Cross Validation ◽  
Systemic Arterial Tree

The early detection and intervention of artery stenosis is very important to reduce the mortality of cardiovascular disease. A novel method for predicting artery stenosis was proposed by using the input impedance of the systemic arterial tree and support vector machine (SVM). Based on the built transmission line model of a 55-segment systemic arterial tree, the input impedance of the arterial tree was calculated by using a recursive algorithm. A sample database of the input impedance was established by specifying the different positions and degrees of artery stenosis. A SVM prediction model was trained by using the sample database. 10-fold cross-validation was used to evaluate the performance of the SVM. The effects of stenosis position and degree on the accuracy of the prediction were discussed. The results showed that the mean specificity, sensitivity and overall accuracy of the SVM are 80.2%, 98.2% and 89.2%, respectively, for the 50% threshold of stenosis degree. Increasing the threshold of the stenosis degree from 10% to 90% increases the overall accuracy from 82.2% to 97.4%. Increasing the distance of the stenosis artery from the heart gradually decreases the overall accuracy from 97.1% to 58%. The deterioration of the stenosis degree to 90% increases the prediction accuracy of the SVM to more than 90% for the stenosis of peripheral artery. The simulation demonstrated theoretically the feasibility of the proposed method for predicting artery stenosis via the input impedance of the systemic arterial tree and SVM.

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