MPI Parallelization for Two-Way Coupled Euler-Lagrange Simulation of Microbubble Enhanced HIFU

2021 ◽  
Author(s):  
Jingsen Ma ◽  
Aswin Gnanaskandan ◽  
Chao-Tsung Hsiao ◽  
Georges L. Chahine
Keyword(s):  
Thermal Effects ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Tissue Ablation ◽  
Computational Domain ◽  
Tumor Treatment ◽  
Time Step ◽  
Thermal Fields ◽  
Before And After ◽  
Gas Volume

Abstract Microbubble enhanced High Intensity Focused Ultrasound (HIFU) is of great interest to tissue ablation for tumor treatment such as in liver and brain cancers, where microbubbles are injected to the targeted region to promote focal heating while reducing pre-focal damage. To accurately characterize the acoustic and thermal fields during this process, a compressible Euler-Lagrange model is used, and a domain decomposition based MPI parallelization scheme is developed for its speedup. The Eulerian computational domain is subdivided into several subdomains, and the Lagrangian bubbles are subdivided based on their locations corresponding to each subdomain. During each time step, MPI processors, each handling one subdomain, are sequentially used to execute 1) the fluid, and 2) bubble computations, 3) followed by the coupling which maps the void fraction from Lagrangian bubbles into Eulerian grids. Steps 1) and 2) are relatively straightforward by routinely following regular MPI procedures. However, step 3) becomes challenging as a bubble near borders needs to spread its effects to cells in different subdomains. This is addressed by a special utilization of ghost cells surrounding each fluid subdomain, which allows bubbles to spread their void effects across subdomain edges without the need of directly exchanging bubble information between subdomains and significantly increasing overhead. This is verified by gas volume conservation before and after spreading the bubble effects. Bubbles' thermal effects are handled in a similar way. This parallelization scheme is validated and illustrated on a typical microbubble enhanced HIFU problem, followed by parallelization scaling tests and efficiency analysis.

MPI Parallelization for Two-Way Coupled Euler-Lagrange Simulation of Microbubble Enhanced HIFU

2020 ◽  
Author(s):  
Jingsen Ma ◽  
Aswin Gnanaskandan ◽  
Chao-Tsung Hsiao ◽  
Georges L. Chahine
Keyword(s):  
Void Fraction ◽  
Focused Ultrasound ◽  
Local Heating ◽  
Computational Cost ◽  
Computation Time ◽  
High Intensity Focused Ultrasound ◽  
Computational Domain ◽  
Time Step ◽  
Before And After ◽  
Coupling Procedure

Abstract Microbubble enhanced High Intensity Focused Ultrasound (HIFU) is of great interest to tissue ablation for tumor treatment such as in liver and brain cancers, in which ultrasonic contrast agent microbubbles are injected to the targeted region to promote local heating while reducing pre-focal damage. To accurately characterize the acoustic and thermal fields during this process, a compressible Euler-Lagrange model is used. The non-linear ultrasound field is modeled using compressible N-S equations on an Eulerian grid, while the microbubbles are tracked as discrete singularities in a Lagrangian fashion with their dynamics computed. Their intimate coupling is realized through the local void fraction, which is computed from the instantaneous bubble volumes and locations, and then fed to the fluid continuum model. Owing to demanding computational cost in real applications, schemes for significant speedup are highly desirable. We present here a MPI parallelization scheme based on domain decomposition for both the continuum fluid and the discrete bubbles. The Eulerian computational domain is subdivided into several subdomains having each the same number of grids, while the bubbles are subdivided based on their locations corresponding to each subdomain. During each computation time step, MPI processors, each handling one subdomain, are 1) first used to execute the fluid computation, and 2) then to execute the bubble computations, 3) followed by the coupling procedure, which maps the void fraction from the Lagrangian bubble solutions into the Eulerian grids. Steps 1) and 2) are relatively straightforward by routinely following regular MPI procedures. However, step 3) becomes challenging as the effect of the bubbles through the void fraction at an Eulerian point near a subdomain border will require information from bubbles located in different subdomains. Similarly, a bubble near a border between subdomains will spread its contribution to the void fraction of different subdomains. This is addressed by a special utilization of ghost cells surrounding each fluid subdomain, which allows bubbles to spread their void fraction effects across subdomain edges without the need of exchanging directly bubble information between subdomains and significantly increasing overhead. This void fraction implementation is verified by gas volume conservation before and after spreading the bubble effects. Other bubble effects such as thermal effects are handled in a similar way. This parallelization scheme is validated and illustrated on a typical microbubble enhanced HIFU problem, followed by parallelization scaling tests and efficiency analysis.

Hybrid MPI-OpenMP Accelerated Euler-Lagrange Simulations of Microbubble Enhanced HIFU

2021 ◽  
Author(s):  
Jingsen Ma ◽  
Xiaolong Deng ◽  
Chao-Tsung Hsiao ◽  
Georges L. Chahine
Keyword(s):  
Focused Ultrasound ◽  
Bubble Dynamics ◽  
Computational Cost ◽  
Coupled Model ◽  
High Intensity Focused Ultrasound ◽  
Navier Stokes ◽  
Computational Domain ◽  
Thermal Fields ◽  
Load Imbalance ◽  
Speed Up

Abstract Microbubble enhanced High Intensity Focused Ultrasound (HIFU) is of great interest to tissue ablation for solid tumor treatments such as in liver and brain cancers, in which contrast agents/microbubbles are injected into the targeted region to promote heating and reduce pre-focal tissue damage. A compressible Euler-Lagrange coupled model has been developed to accurately characterize the acoustic and thermal fields during this process. This employs a compressible Navier-Stokes solver for the ultrasound acoustic field and a discrete singularities model for bubble dynamics. To address the demanding computational cost in practical biological applications, a multi-level hybrid MPI-OpenMP parallelization scheme is developed to take advantage of both scalability of MPI and load balancing of OpenMP. At the first level, the Eulerian computational domain is divided into multiple subdomains and the bubbles are subdivided in groups based on which subdomain they fall into. At the next level, in each subdomain containing bubbles, multiple OpenMP threads are activated to speed up the bubble computations. More OpenMP threads are used inside each subdomain where the bubbles are clustered. By doing this, MPI load imbalance issue due to non-uniformity of bubble presence is compensated. The hybrid MPI-OpenMP Euler-Lagrange solver is used to conduct simulations and physical studies of bubble-enhanced HIFU problems containing a large number of microbubbles. The phenomenon of acoustic shadowing caused by the bubble cloud is then analyzed and discussed. Hybrid parallelization efficiency tests and demonstration of its advantages against using MPI alone are presented.

Non-invasive tissue ablation of kidney tumours by high intensity focused ultrasound

2003 ◽  
Vol 2 (1) ◽  
pp. 56
Author(s):  
A. Häcker ◽  
M.S. Michel ◽  
T. Knoll ◽  
F. Marlinghaus ◽  
P. Alken ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Tissue Ablation ◽  
Non Invasive

scholarly journals An Ultrasound Imaging-Guided Robotic HIFU Ablation Experimental System and Accuracy Evaluations

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Chih Yu An ◽  
Jia Hao Syu ◽  
Ching Shiow Tseng ◽  
Chih-Ju Chang
Keyword(s):  
Standard Deviation ◽  
Ultrasound Imaging ◽  
Focused Ultrasound ◽  
Ultrasound Image ◽  
Experimental System ◽  
High Intensity Focused Ultrasound ◽  
Ultrasound Images ◽  
Tumor Treatment ◽  
Positioning Control ◽  
Hifu Ablation

In recent years, noninvasive thermal treatment by using high-intensity focused ultrasound (HIFU) has high potential in tumor treatment. The goal of this research is to develop an ultrasound imaging-guided robotic HIFU ablation system for tumor treatment. The system integrates the technologies of ultrasound image-assisted guidance, robotic positioning control, and HIFU treatment planning. With the assistance of ultrasound image guidance technology, the tumor size and location can be determined from ultrasound images as well as the robotic arm can be controlled to position the HIFU transducer to focus on the target tumor. After the development of the system, several experiments were conducted to measure the positioning accuracy of this system. The results show that the average positioning error is 1.01 mm with a standard deviation 0.34, and HIFU ablation accuracy is 1.32 mm with a standard deviation 0.58, which means this system is confirmed with its possibility and accuracy.

scholarly journals Multiparametric MRI analysis for the evaluation of MR-guided high intensity focused ultrasound tumor treatment

2015 ◽  
Vol 28 (9) ◽  
pp. 1125-1140 ◽  
Author(s):  
Stefanie J. C. G. Hectors ◽  
Igor Jacobs ◽  
Edwin Heijman ◽  
Jochen Keupp ◽  
Monique Berben ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
Multiparametric Mri ◽  
High Intensity Focused Ultrasound ◽  
Tumor Treatment

scholarly journals HIFU Varicose Vein Treatment Using Veinsound Device Feasibility Study On Sheep

2021 ◽  
Author(s):  
Thomas Charrel ◽  
Bernard Greillier
Keyword(s):  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Local Tissue ◽  
Vein Occlusion ◽  
Saphenous Veins ◽  
Tissue Effects ◽  
Before And After ◽  
Diameter Reduction ◽  
Nonclinical Study ◽  
Severe Grade

The purpose of this nonclinical study was to evaluate the performance (in terms of vein occlusion) and the local tissue effects of echo-guided HIFU (High Intensity Focused Ultrasound) treatments in sheep’s saphenous veins.HIFU treatments were used to treat 4 saphenous veins. Two HIFU doses were evaluated 4s/60J and 7s/105J with and without tumescence injection in perivenous tissues. Before and after treatment, ultrasound scans were performed (at Day 0, 3, 7 and 21). Sheep were then euthanized at D21. Local tissue effects were evaluated based on the macroscopic observations, while the evaluation of the device performance was based on ultrasonic scan.Macroscopically throughout the study duration, for dose of 4s/60J and with tumescence, significant lumens diameter reduction of 84% was observed without skin burns. For doses of 4s/60J without tumescence and 7s/105J skin burns of slight to severe grade was observed along the vein, while no thrombus nor lumen reduction were observed.

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