Physically-based models for Catheter, Guidewire

and Stent simulation

Julien Lenoir Julien Lenoir

Stephane Cotin, Christian Duriez and Stephane Cotin, Christian Duriez and Paul Paul NeumannNeumann

The SIM Group The SIM Group –– CIMIT, MGH, Harvard Medical CIMIT, MGH, Harvard Medical School School

Interventional RadiologyInterventional Radiology

Providing therapy through thehuman vascular system to

prevent stroke.

Interventional DevicesInterventional Devices

Primary Devices: Primary Devices: guidewire and catheterguidewire and catheter

Attributes:Attributes: Flexible, smooth, uncompressible Flexible, smooth, uncompressible

Manipulate:Manipulate: Insert/retract and twist externally Insert/retract and twist externally

Navigation:Navigation: curved tip for vessel junctions curved tip for vessel junctions

Our Goal:Our Goal: To replicate these To replicate these

devices within a simulator todevices within a simulator to

aid in training.aid in training.

ChallengeChallenge

Thin Stiff StructuresThin Stiff Structures

Nested DevicesNested Devices

Multiple Contacts and Sliding Multiple Contacts and Sliding conditionsconditions

Large DeformationsLarge Deformations

Requires High Fidelity for Requires High Fidelity for RadiologistsRadiologists

Previous WorkPrevious Work

General one-dimensional modelsGeneral one-dimensional models Dynamic spline Dynamic spline [Lenoir et al 02, Nocent & Remion 01][Lenoir et al 02, Nocent & Remion 01] Static Cosserat model Static Cosserat model [Pai 02][Pai 02]

Specific catheter simulationSpecific catheter simulation Rigid bodies and joints (multi-body dynamics) Rigid bodies and joints (multi-body dynamics)

[Dawson et al 00][Dawson et al 00] Linear elastic FEM Linear elastic FEM [Nowinski 01][Nowinski 01] Incremental FEM model Incremental FEM model [Cotin et al 05][Cotin et al 05]

PhysicsPhysics--based based RepresentationRepresentation

Base ModelBase Model 6 Degrees of Freedom (translation + rotation)6 Degrees of Freedom (translation + rotation) Linear elasticityLinear elasticity

OptimizationOptimization IncrementalIncremental FEM for FEM for

geometric nonlinearitygeometric nonlinearity PerformancePerformance improvement throughimprovement through

sub-structure analysissub-structure analysis

Collision DetectionCollision Detection Accomplished through optimized vascular Accomplished through optimized vascular

modelmodel Oriented graph Oriented graph Each beam node of a device is tracked usingEach beam node of a device is tracked using

Proximity measureProximity measure Temporal coherenceTemporal coherence

Surface Partitioned Surface Partitioned return active sectionreturn active section test local triangle subsettest local triangle subset

Anatomical model is described inanother paper on pp 273-278.

Collision ResponseCollision Response Collision response needs to account for Collision response needs to account for

multiple contacts and sliding conditionsmultiple contacts and sliding conditions Quadratic Programming proved to be too time Quadratic Programming proved to be too time

consumingconsuming

Our Approach: Iterative Gauss SeidelOur Approach: Iterative Gauss Seidel Use penalty method locallyUse penalty method locally Propagate change to other nodesPropagate change to other nodes Iterate checking other nodes until no Iterate checking other nodes until no

violationsviolations

ResultsResults

ResultsResults

Co-axial Co-axial Catheter/GuidewireCatheter/Guidewire

One unified device rather than twoOne unified device rather than two Modulate material properties based on regions:Modulate material properties based on regions:

Overlapping Overlapping Guidewire onlyGuidewire only Catheter only Catheter only

Locally update material properties using Locally update material properties using Halpin-Tsai equations.Halpin-Tsai equations.

Results Results –– Video 2 Video 2

StentsStents Thin cylindrical metallic meshThin cylindrical metallic mesh Implanted to open partially blocked Implanted to open partially blocked

vessels restoring blood flowvessels restoring blood flow Expands radially when releasedExpands radially when released

StentsStents Modeling Issues:Modeling Issues:

Connect an additional surface to ‘core’ beam Connect an additional surface to ‘core’ beam modelmodel

Surface constrained and expands when releasedSurface constrained and expands when released Perform collision test on surface elementsPerform collision test on surface elements

Coupled relationship between surface and Coupled relationship between surface and beam nodesbeam nodes Forces on surface elements propagated to beam Forces on surface elements propagated to beam

nodesnodes Currently working on local vessel deformationCurrently working on local vessel deformation

Surface Elements

Beam nodes

Stent VideoStent Video

Conclusions and Ongoing Conclusions and Ongoing WorkWork

ConclusionsConclusions Real-time robust physics-based representation for Real-time robust physics-based representation for

wire-like deviceswire-like devices Defined composite technique of nested devicesDefined composite technique of nested devices Demonstrated extensions: stentsDemonstrated extensions: stents

Ongoing workOngoing work Local and global deformation of anatomical modelLocal and global deformation of anatomical model Develop angioplasty balloon using similar Develop angioplasty balloon using similar

principlesprinciples InvestigatingInvestigating coilscoils Finalize complete simulation systemFinalize complete simulation system

AcknowledgementsAcknowledgements– Team –

Xunlei WuVincent LubozJulien Lenoir

Christian DuriezPaul NeumannStephane Cotin

– Funding –

TATRCCIMIT

http://thesimgroup.org/