na-mic national alliance for medical image computing toward automating patient-specific finite...

NA-MICNational Alliance for Medical Image Computing http://na-mic.org

Toward Automating Patient-Specific Finite Element Model Development

Nicole M. Grosland, Vincent A. Magnotta,

Kiran H. Shivanna, Steve Pieper, Curt Lisle

National Alliance for Medical Image Computing http://na-mic.org

Patient Specific Models

• In order to bring FE to the “bedside” for guiding surgical procedures the technique must be unencumbered from the image segmentation and mesh generation process

• Overcome the limitations associated with individualized, or patient-specific models


Goal and Obstacles

• Goal– Integrate meshing generation tool into Slicer3

that would allow for the rapid development of hexahedral meshes from imaging data

• Obstacles– IA-FEMesh was relatively immature– Slicer3 was relatively immature


Solution

• Moved development of IA-FEMesh to KWWidgets

• Built an infrastructure that could be easily integrated into Slicer3

• Added support to Slicer3 for new types of objects

– Unstructured grids

– New visualization pipelines

• Allowed development to progress in parallel


Integrating with Slicer3• VTK rendering pipelines

converted to use MRML display nodes for rendering in Slicer3

• Separate MRML display nodes were created for each datatype in the meshing workflow


Workflow

Slicer3•Load Images•Segmentation-Manual-EMS

•Surface Generation

IA-FEMesh Module•Building Block(s)

- Creation- Editing- Mesh Density

•Mesh Generation- Quality Eval- Improvement

•Material Properties- Constant- Image-Based- Element Sets

•Boundary Conditions- Node Sets

Analysis•ABAQUS•Other packages- Ansys- Adina- Etc…


Significant Achievements

• Created a number of new 3D VTK Widgets

• Developed a new workflow style to simplify mesh development

• Developed a tutorial for the meshing workflow and held a workshop

• Integrated this tool into a Finite Element course

• Meshed a number of complex anatomic structures


3D VTK Widgets


Meshing Module

Slicer3 Integration


FEA Course: Student Work


Example Meshes


Publications• Grosland NM, Bafna R, Magnotta VA., Automated hexahedral meshing of anatomic structures

using deformable registration. Comput Methods Biomech Biomed Engin. Comput Methods Biomech Biomed Engin. 2009 Feb;12(1):35-43. [PMC Journal - In Process]

• Grosland NM, Shivanna KH, Magnotta VA, Kallemeyn NA, DeVries NA, Tadepalli SC, Lisle C., IA-FEMesh: An open-source, interactive, multiblock approach to musculoskeletal finite element model development, Comput Methods Programs Biomed. 2009 Apr;94(1):96-107. [NIHMS101589]

• Kallemeyn NA, Tadepalli SC, Shivanna KH, Grosland NM, An interactive multiblock approach to meshing the spine, Comput Methods Programs Biomed. 2009, Sep;95(3):227-35..

• DeVries NA, Shivanna KH, Tadepalli SC, Magnotta VA, Grosland NM, IA-FEMesh: Anatomic FE models – a check of mesh accuracy and validity. Iowa Orthop J, Iowa Orthop J. 2009; 29: 48–54. [PMCID: PMC2723692]

• Tadepalli, S.C., K.H. Shivanna, V.A. Magnotta, N.A. Kallemeyn, and N.M. Grosland, Toward the development of virtual surgical tools to aid orthopaedic FE analyses. Advances in Signal Processing (Special edition: Image Processing and Analysis in Biomechanics), 2009 (accepted).

• Ramme AJ, Shivanna KH, Magnotta VA, Grosland NM, Automated Building Block Definitions to Aid Multiblock Hexahedral Meshing of Bony Structures (submitted).

• Shivanna KH, Magnotta VA, Grosland NM, Feature based multiblock finite element mesh generation, Comput Methods Programs Biomed. (submitted)


Status

• Meshing workflow is complete

– All 3D widgets work in Slicer3

• Completing sharing of data between Slicer3 and meshing module

– Scheduling visit to Iowa by Curt Lisle to complete this work

• Putting final touches on testing framework


Future Work

• Submission of software development and maintenance grant– Mesh improvement strategies– Automate building block definitions– Mapped meshing

• Renewal of NA-MIC Collaboration Grant (EB005973)– Development of tools to simulate surgical simulations– Enhancements of meshing algorithms to accommodate

increasingly complex anatomical structures– Mesh improvement strategies– Validate these approaches


Acknowledgements

• Grant funding NIH/NIBIB– R21 (EB001501)– R01 (EB005973)

• Nicole Kallemeyn, Nicole DeVries, Esther Gassman,

Ritesh Bafna, Srinivas Tadepalli, Austin Ramme, Wen Li,Dr. Brian Adams

na-mic national alliance for medical image computing toward automating patient-specific finite...

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