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Creating and Simulating Skeletal Muscle from the Visible Human Data Set. Authors: Joseph Teran Eftychios Sifakis Silvia S. Blemker Victor Ng-Thow-Hing Cynthia Lau Ronald Fedkiw. Presented By : Federico Bermudez. PROBLEM.
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Creating and Simulating Skeletal Muscle from the Visible Human Data Set • Authors: • Joseph Teran • Eftychios Sifakis • Silvia S. Blemker • Victor Ng-Thow-Hing • Cynthia Lau • Ronald Fedkiw Presented By: Federico Bermudez MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
PROBLEM • Create anatomically realistic simulations of the human musculoskeletal system. • Create visually accurate simulations of the interactions between muscles and bones. • This paper present a method for creating such simulations using the visible human data set. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
MOTIVATION • Anatomically and visually accurate simulations of the musculoskeletal system are critical in: • biomechanics • biomedical engineering • surgery simulation • computer graphics MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
APPROACH PRIOR & RELATED WORK • Prior work • Simple less accurate models encompassing many muscles. • Complex models that only simulate a few number of muscles. • These models are less visually accurate. • Related work • Seems to be concentrated on the use of the Finite Element Method (FEM), the Finite Volume Method (FVM), and tetrahedral meshes MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
APPROACH MODEL CREATION The Visible Human Data Set Run by the U.S. National Library Of Medicine Consists of MRI, CT, and anatomical Images Male data set released in Nov 1994 • Joseph Paul Jernigan (38-year-old Texas murderer executed 5 Aug 1993) • cadaver was frozen and cut (1871 axial slices at 1 millimeter intervals) • Photographed and digitized – 15 GB Female data set released in Nov 1995 • 59-year-old Maryland housewife who died from a heart attack • cadaver was frozen and cut (5189 axial slices at 0.33 millimeter intervals) • Photographed and digitized – 40 GB MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
APPROACH MODEL CREATION The Visible Human Data Set Problems with the data set • Male brain slightly swollen by the freezing process • Small blood vessels were collapsed by the freezing process • His inner ear ossicles were lost during preparation Site: http://www.nlm.nih.gov/research/visible/ 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 6
APPROACH CT Scan Color Cryosections Thorax subset MODEL CREATION The Visible Human Data Set 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 7
APPROACH MODEL CREATION The Visible Human Data Set 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 8
APPROACH MODEL CREATION Repairing Errors 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 9
APPROACH MODEL CREATION Meshing Bone and Muscle 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 10
APPROACH MODEL CREATION Meshing Bone and Muscle 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 11
APPROACH MODEL CREATION Tendon and Bone Attachment Designation assign tendon, bone attachments, and muscle properties to sections of the mesh 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 12
APPROACH MODEL CREATION B-Spline Fiber Representation Use B-spline solids to assign fiber directions to individual tetrahedrons. 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 13
APPROACH MODEL CREATION Skeletal Motion • Contraction of the muscles drives the motion of bones. • In this model, the skeleton drives the motion and contraction of muscles, tendons, and surrounding tissue. • A realistic model involves intricate knowledge of bones and joints interaction , often requiring multiple degrees of freedom to describe their movements. • The Obstacle-set Method was used to modeled the paths of the muscles. • Cylinders and spheres were used to compute muscles and bones collisions. 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 14
APPROACH MODEL CREATION Skeletal Motion 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 15
APPROACH MODEL CREATION Skeletal Motion 21 Mar 2007 MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH 16
APPROACH FINITE VOLUME METHOD • FVM more intuitive than the finite element method (FEM) • FVM reduces the stress inside a tetrahedron to a simple multidimensional force pushing on each face. • The inverting FVM algorithm developed from the FVM facilitates the simulation of objects that must undergo deformation and return to their original or partial shape. • Video – 01 & 02 show simulations using the inverting FVM. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
APPROACH CONSTITUTIVE MODEL FOR MUSCLE • An strain energy function is used to model the contracting of the muscles. • Model includes only what is necessary to produce bulk length-based contraction along the muscle fiber direction. • As we will see on the video, the bulk deformations of the muscles are very subtle. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
APPROACH EMBEDDING FRAMEWORK • The complete model of the upper limb consist of over 30 muscles constructed with over 10 million tetrahedra. • A dynamic Free Form Deformation embedding scheme was used to reduce the computational cost. • The BCC grid size used resulted in a tenfold reduction in the size of the simulation mesh. • Time step restriction for stability was relaxed by a factor of 25. • These factors enabled the full finite element simulation at rates of 4 minutes per frame on a Xeon 3.06 GHz CPU. • A nonmanifold simulation mesh is obtained by collapsing equivalent vertices. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
APPROACH FASCIA AND CONNECTIVE TISSUES • Muscles are enclosed in a network of connective tissue that keep them in close contact during motion. • Model enforces a state of frictionless contact between the muscles. • In essence the intersection between different muscles is determined and recalculated each time during motion in order to maintain the muscle tissues in close contact. • Video – 03 shows the simulation without fascia. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
APPROACH SIMULATING SKELETAL MUSCLE Run videos • Video – 04 - Frontal View • Video – 05 - Side View MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
Evaluation • The construction of the muscles, tendons, and bones seems to be correct. • I think the simulation shows the compression and relaxation if the muscles visually accurate. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
Conclusion & Future Work • The authors successfully created a visually accurate simulation of the interaction of the bones, muscle, and underlying tissue of the human right upper limb. • Current hardware and algorithm technology still too complex to achieve whole body simulations. • Create subject-specific models with MRI and CT data. • Morph VHP data set to match specific subject or body type using anatomical landmarks. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH
Questions • How much more complex would be to simulate the whole body. • Can this technique be use to simulate the involuntary muscles such the hear heart? • Can this technique be applied to the design of artificial limbs. MSIM 842 VISUALIZATION II INSTRUCTOR: JESSICA R. CROUCH