Method and System for Patient-Specific Hemodynamic Assessment of Virtual Stent Implantation

• US 20130144573A1
• Filed: 12/06/2011
• Published: 06/06/2013
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens Corp. (Siemens AG)
• Inventors: Sharma, Puneet, Mihalef, Viorel, Georgescu, Bogdan, Comaniciu, Dorin, Lonasec, Razvan Loan
• Granted Patent: US 8,983,809 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: G06F 2111/00 Details relating to CAD techniques
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

A method and system for assessment of virtual stent implantation in an aortic aneurysm is disclosed. A patient-specific 4D anatomical model of the aorta is generated from the 4D medical imaging data. A model representing mechanical properties of the aorta wall is adjusted to reflect changes due to aneurysm growth at a plurality of time stages. A stable deformation configuration of the aorta is generated for each time stages by performing fluid structure interaction (FSI) simulations using the patient-specific 4D anatomical model at each time stage based on the adjusted model representing the mechanical properties of the aorta wall at each time stage. Virtual stent implantation is performed for each stable deformation configuration of the aorta and FSI simulations are performed for each virtual stent implantation.

Claims

1. A method for assessment of virtual stent implantation in an aortic aneurysm, comprising:

generating a patient-specific 4D anatomical model of the aorta from the 4D medical imaging data;

adjusting a model representing mechanical properties of the aorta wall to reflect changes due to aneurysm growth at a plurality of time stages;

generating a stable deformation configuration of the aorta for each of the plurality of time stages by performing fluid structure interaction (FSI) simulations using the patient-specific 4D anatomical model at each time stage based on the adjusted model representing the mechanical properties of the aorta wall at each time stage;

performing virtual stent implantation for each stable deformation configuration of the aorta; and

performing FSI simulations for each virtual stent implantation.

2. The method of claim 1, further comprising:

determining at least one hemodynamic parameter for each virtual stent implantation based on results of the FSI simulations for each virtual stent implantation.

3. The method of claim 2, wherein the step of determining at least one hemodynamic parameter for each virtual stent implantation based on results of the FSI simulations for each virtual stent implantation comprises:

determining at least one of wall shear stress and vorticity for each virtual stent implantation based on velocity and pressure values resulting from the FSI simulations for each virtual stent implantation.

4. The method of claim 1, wherein the step of generating a patient-specific 4D anatomical model of the aorta from the 4D medical imaging data comprises:

generating an aorta mesh in each of a plurality of frames of the 4D medical imaging data using piece-wise aorta segmentation.

5. The method of claim 1, wherein the step of adjusting a model representing mechanical properties of the aorta wall to reflect changes due to aneurysm growth at a plurality of time stages comprises:

characterizing the mechanical properties of the aorta wall using a mathematical model based on an underlying structural analysis of three layers of the aortic wall under internal pressure; and

adjusting at least one parameter of the mathematical model characterizing the mechanical properties of the aorta wall at each of the plurality of time stages to reflect changes in the at least one parameter due to a progressively growing aneurysm.

6. The method of claim 5, wherein the step of adjusting at least one parameter of the mathematical model characterizing the mechanical properties of the aorta wall at each of the plurality of time stages to reflect changes in the at least one parameter due to a progressively growing aneurysm comprises:

adjusting a parameter representing stiffness of collagen fibers in the aorta wall at each of the plurality of time stages.

7. The method of claim 1, wherein the step of generating a stable deformation configuration of the aorta for each of the plurality of time stages by performing fluid structure interaction (FSI) simulations using the patient-specific 4D anatomical model at each time stage based on the adjusted model representing the mechanical properties of the aorta wall at each time stage comprises, for each of the plurality of time stages:

simulating blood flow in the patient-specific 4D anatomical model of the aorta at a current time step;

calculating a deformation of the aorta wall at the current time step based on the simulated blood flow at the current time step and the adjusted model representing the mechanical properties of the aorta wall; and

repeating the simulating and calculating steps for a plurality of time steps.

8. The method of claim 7, wherein the step of simulating blood flow in the patient-specific 4D anatomical model of the aorta at a current time step comprises:

simulating the blood flow in the patient-specific 4D anatomical model of the aorta by solving Navier-Stokes equations constrained by a geometry of the patient-specific 4D anatomical model of the aorta at the current time step using a level set framework.

9. The method of claim 7, wherein the step of simulating blood flow in the patient-specific 4D anatomical model of the aorta at a current time step comprises:

calculating pressure at a wall interface of the aorta at the current time step due to the simulated blood flow.

10. The method of claim 9, wherein the step of calculating a deformation of the aorta wall at the current time step based on the simulated blood flow at the current time step comprises:

calculating a deformation of the aorta wall due to the pressure at the wall interface of aorta.

11. The method of claim 1, wherein the step of performing virtual stent implantation for each stable deformation configuration of the aorta comprises:

virtually simulating stent deployment at an aortic aneurysm in each stable deformation configuration of the aorta.

12. An apparatus for assessment of virtual stent implantation in an aortic aneurysm, comprising:

means for generating a patient-specific 4D anatomical model of the aorta from the 4D medical imaging data;

means for adjusting a model representing mechanical properties of the aorta wall to reflect changes due to aneurysm growth at a plurality of time stages;

means for generating a stable deformation configuration of the aorta for each of the plurality of time stages by performing fluid structure interaction (FSI) simulations using the patient-specific 4D anatomical model at each time stage based on the adjusted model representing the mechanical properties of the aorta wall at each time stage;

means for performing virtual stent implantation for each stable deformation configuration of the aorta; and

means for performing FSI simulations for each virtual stent implantation.

13. The apparatus of claim 12, further comprising:

means for determining at least one hemodynamic parameter for each virtual stent implantation based on results of the FSI simulations for each virtual stent implantation.

14. The apparatus of claim 13, wherein the means for determining at least one hemodynamic parameter for each virtual stent implantation based on results of the FSI simulations for each virtual stent implantation comprises:

means for determining at least one of wall shear stress and vorticity for each virtual stent implantation based on velocity and pressure values resulting from the FSI simulations for each virtual stent implantation.

15. The apparatus of claim 12, wherein the means for generating a patient-specific 4D anatomical model of the aorta from the 4D medical imaging data comprises:

means for generating an aorta mesh in each of a plurality of frames of the 4D medical imaging data using piece-wise aorta segmentation.

16. The apparatus of claim 12, wherein the means for adjusting a model representing mechanical properties of the aorta wall to reflect changes due to aneurysm growth at a plurality of time stages comprises:

means for characterizing the mechanical properties of the aorta wall using a mathematical model based on an underlying structural analysis of three layers of the aortic wall under internal pressure; and

means for adjusting at least one parameter of the mathematical model characterizing the mechanical properties of the aorta wall at each of the plurality of time stages to reflect changes in the at least one parameter due to a progressively growing aneurysm.

17. The apparatus of claim 16, wherein the means for adjusting at least one parameter of the mathematical model characterizing the mechanical properties of the aorta wall at each of the plurality of time stages to reflect changes in the at least one parameter due to a progressively growing aneurysm comprises:

means for adjusting a parameter representing stiffness of collagen fibers in the aorta wall at each of the plurality of time stages.

18. The apparatus of claim 12, wherein the means for generating a stable deformation configuration of the aorta for each of the plurality of time stages by performing fluid structure interaction (FSI) simulations using the patient-specific 4D anatomical model at each time stage based on the adjusted model representing the mechanical properties of the aorta wall at each time stage comprises:

means for simulating blood flow in the patient-specific 4D anatomical model of the aorta at a current time step; and

means for calculating a deformation of the aorta wall at the current time step based on the simulated blood flow at the current time step and the adjusted model representing the mechanical properties of the aorta wall.

19. The apparatus of claim 12, wherein the means for performing virtual stent implantation for each stable deformation configuration of the aorta comprises:

means for virtually simulating stent deployment at an aortic aneurysm in each stable deformation configuration of the aorta.

20. A non-transitory computer readable medium encoded with computer executable instructions for assessment of virtual stent implantation in an aortic aneurysm, the computer executable instructions defining steps comprising:

generating a patient-specific 4D anatomical model of the aorta from the 4D medical imaging data;

adjusting a model representing mechanical properties of the aorta wall to reflect changes due to aneurysm growth at a plurality of time stages;

generating a stable deformation configuration of the aorta for each of the plurality of time stages by performing fluid structure interaction (FSI) simulations using the patient-specific 4D anatomical model at each time stage based on the adjusted model representing the mechanical properties of the aorta wall at each time stage;

performing virtual stent implantation for each stable deformation configuration of the aorta; and

performing FSI simulations for each virtual stent implantation.

21. The non-transitory computer readable medium of claim 20, further comprising computer executable instructions defining the step of:

determining at least one hemodynamic parameter for each virtual stent implantation based on results of the FSI simulations for each virtual stent implantation.

22. The non-transitory computer readable medium of claim 21, wherein the computer executable instructions defining the step of determining at least one hemodynamic parameter for each virtual stent implantation based on results of the FSI simulations for each virtual stent implantation comprise computer executable instructions defining the step of:

determining at least one of wall shear stress and vorticity for each virtual stent implantation based on velocity and pressure values resulting from the FSI simulations for each virtual stent implantation.

23. The non-transitory computer readable medium of claim 20, wherein the computer executable instructions defining the step of generating a patient-specific 4D anatomical model of the aorta from the 4D medical imaging data comprise computer executable instructions defining the step of:

generating an aorta mesh in each of a plurality of frames of the 4D medical imaging data using piece-wise aorta segmentation.

24. The non-transitory computer readable medium of claim 20, wherein the computer executable instructions defining the step of adjusting a model representing mechanical properties of the aorta wall to reflect changes due to aneurysm growth at a plurality of time stages comprise computer executable instructions defining the steps of:

characterizing the mechanical properties of the aorta wall using a mathematical model based on an underlying structural analysis of three layers of the aortic wall under internal pressure; and

adjusting at least one parameter of the mathematical model characterizing the mechanical properties of the aorta wall at each of the plurality of time stages to reflect changes in the at least one parameter due to a progressively growing aneurysm.

25. The non-transitory computer readable medium of claim 24, wherein the computer executable instructions defining the step of adjusting at least one parameter of the mathematical model characterizing the mechanical properties of the aorta wall at each of the plurality of time stages to reflect changes in the at least one parameter due to a progressively growing aneurysm comprise computer executable instructions defining the step of:

adjusting a parameter representing stiffness of collagen fibers in the aorta wall at each of the plurality of time stages.

26. The non-transitory computer readable medium of claim 20, wherein the computer executable instructions defining the step of generating a stable deformation configuration of the aorta for each of the plurality of time stages by performing fluid structure interaction (FSI) simulations using the patient-specific 4D anatomical model at each time stage based on the adjusted model representing the mechanical properties of the aorta wall at each time stage comprise computer executable instructions defining the steps of, for each of the plurality of time stages:

simulating blood flow in the patient-specific 4D anatomical model of the aorta at a current time step;

calculating a deformation of the aorta wall at the current time step based on the simulated blood flow at the current time step and the adjusted model representing the mechanical properties of the aorta wall; and

repeating the simulating and calculating steps for a plurality of time steps.

27. The non-transitory computer readable medium of claim 20, wherein the computer executable instructions defining the step of performing virtual stent implantation for each stable deformation configuration of the aorta comprise computer executable instructions defining the step of:

virtually simulating stent deployment at an aortic aneurysm in each stable deformation configuration of the aorta.