Outline Outline Tissue Modeling and Tissue Modeling and Tissue - PDF document

Outline Outline Tissue Modeling and Tissue Modeling and � Tissue characteristics Tissue characteristics � Characterization � Tissue data sources Tissue data sources Characterization � � Collecting and characterizing tissue Collecting and characterizing tissue � M. Cenk Cavusoglu, PhD M. Cenk Cavusoglu, PhD properties properties cavusoglu@case.edu cavusoglu@case.edu � Tissue damage Tissue damage � Case Western Reserve University Case Western Reserve University � Human sensitivity to stiffness Human sensitivity to stiffness � Dept. of Electrical Eng. and Computer Sci Sci. . Dept. of Electrical Eng. and Computer http://vorlon.cwru.edu/~mcc14/ http://vorlon.cwru.edu/~mcc14/ http://simcen.usuhs.mil/miccai2003 http://simcen.usuhs.mil/miccai2003 Simulation for Medical Training – MICCAI 2003 Tissue is Extremely Complex Tissue is Extremely Complex Tissue is Extremely Complex Tissue is Extremely Complex � Nonlinear stress Nonlinear stress- -strain relationship strain relationship � � Properties change after removal from body Properties change after removal from body � Large deformations possible before yield ( Large deformations possible before yield (Fung Fung, 1993): , 1993): � � – Tendons 2 – Tendons 2- -5% 5% � Properties vary with: Properties vary with: � – Muscle 15% Muscle 15% – – species – species – Skin 40% – Skin 40% – age – age – Vessels 60% – Vessels 60% – sex – sex – – Mesentary Mesentary 100 100- -200% 200% � Viscoelastic Viscoelastic – in vivo stress state – in vivo stress state � Properties are function of time Properties are function of time – muscle activation muscle activation – � Inhomogeneous Inhomogeneous � – etc. etc. – Properties vary through tissue thickness Properties vary through tissue thickness � Anisotropic Anisotropic � Properties vary with direction Properties vary with direction Simulation for Medical Training – MICCAI 2003 Simulation for Medical Training – MICCAI 2003 Sources of Tissue Data Sources of Tissue Data Data from Biomechanics Literature Data from Biomechanics Literature � Sources: Sources: Fung Fung, Yamada, Abe, etc. , Yamada, Abe, etc. � Biomechanics literature Biomechanics literature � � � Ex vivo testing of animal or cadaver tissues Ex vivo testing of animal or cadaver tissues � � Ex vivo, from human or animal cadavers Ex vivo, from human or animal cadavers � – Allows precise control of sample geometry, multi – Allows precise control of sample geometry, multi- -axial axial � Tissue is “conditioned” by repeated cycling Tissue is “conditioned” by repeated cycling � testing testing � In vivo testing of animal or human tissue In vivo testing of animal or human tissue � – Allows natural tissue state (in typical stress state, Allows natural tissue state (in typical stress state, – perfused with blood, with muscle activation) perfused with blood, with muscle activation) � Force and position sensors on surgical instrument Force and position sensors on surgical instrument � – Measure interaction forces too complex to model – Measure interaction forces too complex to model Simulation for Medical Training – MICCAI 2003 Simulation for Medical Training – MICCAI 2003

Tissue Extension Device Tissue Extension Device Tissue Conditioning Tissue Conditioning • Brouwer et al., 2000 • For in vivo or ex vivo testing of animal tissue Stress- Stress -strain characteristic strain characteristic � � changes as tissue is changes as tissue is stretched for repeated stretched for repeated cycles cycles – Data in biomechanics – Data in biomechanics literature is usually literature is usually “conditioned” by “conditioned” by multiple cycles multiple cycles – – But tissue in vivo may But tissue in vivo may not be in similar state! not be in similar state! Simulation for Medical Training – MICCAI 2003 Experimental Results from Tendick et al. (2000) Simulation for Medical Training – MICCAI 2003 Figure courtesy of F. Tendick, UC San Francisco Tissue Uniaxial Uniaxial Extension Extension Tissue Uniaxial Uniaxial Extension Extension Tissue Tissue Load-displacement is exponential... … giving linear slope vs. load λ = α βλ λ = α βλ F ( ) e F ( ) e where λ is the Lagrangian dF ⇒ λ = β F stretch ratio l/l 0- d • Easier for fitting parameters Experimental Results from Tendick et al. (2000) Experimental Results from Tendick et al. (2000) Simulation for Medical Training – MICCAI 2003 Simulation for Medical Training – MICCAI 2003 Tissue Compression Tissue Compression Viscoelasticity Viscoelasticity ∑ − v t C e Rosen et al., 1999 Rosen et al., 1999 � i � = G ( t ) i Works for 3- -D tissues and D tissues and Works for 3 ∑ � � C friable tissues that cannot be friable tissues that cannot be i grasped for extension grasped for extension Valid for palpation tasks Valid for palpation tasks � Very difficult to fit: Very difficult to fit: � � � extremely sensitive to extremely sensitive to small changes in data small changes in data � But humans aren’t But humans aren’t � very sensitive to slow very sensitive to slow changes anyway Photo courtesy of Prof. Blake Hannaford, changes anyway University of Washington Simulation for Medical Training – MICCAI 2003 Experimental Results from Tendick et al. (2000) Simulation for Medical Training – MICCAI 2003

Force Sensors on Instruments Force Sensors on Instruments Tissue Compression Tissue Compression � Ottensmeyer Ottensmeyer & Salisbury: device to measure & Salisbury: device to measure � indentation, including high frequency viscous indentation, including high frequency viscous properties properties Photo courtesy of Prof. Blake Hannaford, University of Washington � Vuskovic Vuskovic et al.: suction device; analysis to extract et al.: suction device; analysis to extract � � Measure interaction forces too complex to model Measure interaction forces too complex to model � modulus from measurements modulus from measurements � Force signatures during actual procedure Force signatures during actual procedure � � Carter et al.: puncture forces Carter et al.: puncture forces � � Position tracking possible also Position tracking possible also � � Ophir Ophir et al. Ultrasound based estimation of tissue et al. Ultrasound based estimation of tissue � stiffness (linear) stiffness (linear) Simulation for Medical Training – MICCAI 2003 Simulation for Medical Training – MICCAI 2003 Typical Data: Driving Needle Through Typical Data: Driving Needle Through Instrumented Scissors and Clamp Instrumented Scissors and Clamp Small Intestine Small Intestine • One-axis force sensor measures cutting or spreading forces Curved Metzenbaum Scissors Curved Kelly Clamp Figure courtesy of F. Tendick, UC San Francisco Experimental Results from Tendick et al. (2000) Simulation for Medical Training – MICCAI 2003 Simulation for Medical Training – MICCAI 2003 Modeling of Needle Insertion Modeling of Needle Insertion Modeling of Needle Insertion Modeling of Needle Insertion � S.P. S.P. Dimaio Dimaio & S.E. & S.E. Salcudean Salcudean (2003) (2003) � � C. Simone and A. Okamura (2002) C. Simone and A. Okamura (2002) � Simulation for Medical Training – MICCAI 2003 Images from DiMaio and Salcudean (2003) Simulation for Medical Training – MICCAI 2003 Images and Figures from Simone and Okamura (2002)