Patient-Specific Liver Ablation Simulation Using Bio-Heat Models

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Solution Overview

Problem

Current ablation therapies for liver tumors, such as radiofrequency ablation, face challenges in achieving optimal tumor destruction due to variations in tissue properties and the impact of hepatic blood vessels, which can reduce treatment efficiency and require multiple procedures.

Innovation Solution

A patient-specific simulation and planning system using medical imaging data to model heat diffusion, blood flow, and cellular necrosis, allowing for personalized ablation planning and refinement based on individual tissue parameters, optimizing probe placement and heat delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If RFA is performed using standard protocols, then the procedure can be completed with existing equipment and techniques, but the treatment efficiency is reduced due to heat dissipation by hepatic blood vessels and variability in tissue properties

Engineering Contradiction:
Improvetreatment efficiencyVSAvoidablation success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary action by creating patient-specific computational models of heat diffusion and blood flow before the actual RFA procedure. Virtual ablation simulations are conducted to predict temperature distribution and necrosis patterns, allowing optimization of probe placement and power delivery parameters in advance, thereby improving treatment efficiency and success rate while accounting for individual tissue properties and vascular anatomy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by iteratively refining the computational model based on comparison between simulated ablation outcomes and actual clinical observations from previous procedures or intraoperative measurements. This feedback loop enables continuous improvement of the patient-specific model accuracy, allowing real-time optimization of ablation parameters to overcome heat dissipation by blood vessels and tissue variability

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If multiple successive ablations are performed to achieve optimal tumor destruction, then the completeness of tumor necrosis is improved, but the treatment time and number of procedures increase

Engineering Contradiction:
Improvetumor destruction completenessVSAvoidnumber of procedures
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs preliminary action by conducting virtual ablation simulations to predict the outcomes of single or multiple ablation procedures before actual treatment. These simulations allow optimization of probe placement, orientation, and power delivery parameters in advance, enabling achievement of complete tumor necrosis in fewer actual procedures and reducing overall treatment time while maintaining high precision in tumor destruction

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates virtual copies of the patient's anatomy and tissue properties through computational modeling. These digital twins allow testing and optimization of multiple ablation scenarios without additional time loss, enabling selection of the optimal treatment plan that achieves complete tumor destruction in the minimum number of procedures

Inventive Principle:
Principle #26Copying

3Measurement precision

If patient-specific tissue parameters are used to personalize ablation planning, then the accuracy of temperature prediction and necrosis estimation is improved, but the complexity of the planning system increases

Engineering Contradiction:
Improvetemperature prediction accuracyVSAvoidplanning system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system creates simplified virtual copies (computational models) of complex patient-specific tissue properties and vascular anatomy. These digital representations capture essential thermal and hemodynamic characteristics while remaining computationally tractable, enabling accurate temperature prediction and necrosis estimation without requiring excessively complex planning systems that would be difficult to implement clinically

Inventive Principle:
Principle #26Copying

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the accuracy and effectiveness of tumor ablation by simulating and visualizing temperature and necrosis maps, enabling more precise and targeted treatment planning, improving the success rate of ablation procedures and allowing for iterative refinement with each treatment.

Implementation Method 1

The forward model of RFA, which relies on patient medical images, is based on a computational model of heat diffusion, cellular necrosis, and a blood flow solver

Methodology Applied
Scientific EffectHeat diffusion: Conduction (thermal)

Implementation Method 2

a blood flow solver which simultaneously model blood circulation in the liver vessels and the liver parenchy

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

A patient-specific bio-heat model combining blood flow in the liver parenchyma and vessels, heat diffusion, and cellular necrosis in the liver

Methodology Applied
Scientific EffectBio-heat transfer: Conduction (thermal)

Data Source

PatentUS10402535B2System and method for personalized computation of tissue ablation extent based on medical images
Publication Date: 2019.09.03 SIEMENS HEALTHINEERS AG
  • US10402535B2 patent drawing
  • US10402535B2 patent drawing
  • US10402535B2 patent drawing

AI summary

A method and system for personalized computation of tissue ablation extent based on medical images of a patient is disclosed. A patient-specific anatomical model of the liver and liver vessels is estimated from medical image data of a patient. Blood flow in the liver and liver vessels is simulated. An ablation simulation is performed that uses a bio-heat model to simulate heat diffusion due to an ablation based on the simulated blood flow and a cellular necrosis model to simulate cellular necrosis in the liver based on the simulated heat diffusion. Personalized tissue parameters of the bio-heat model and the cellular necrosis model are estimated based on observed results of a preliminary ablation procedure. Planning of the ablation procedure is then performed using the personalized bio-heat equation and the cellular necrosis model. The model can be subsequently refined as more ablation observations are obtained.