title: High resolution bone material property assignment yields robust subject specific finite element models of complex thin bone structures.
abstract: Accurate finite element (FE) modeling of complex skeletal anatomy requires high resolution in both meshing and the heterogeneous mapping of material properties onto the generated mesh. This study introduces Node-based elastic Modulus Assignment with Partial-volume correction (NMAP) as a new approach for FE material property assignment to thin bone structures. The NMAP approach incorporates point spread function based deblurring of CT images, partial-volume correction of CT image voxel intensities and anisotropic interpolation and mapping of CT intensity assignment to FE mesh nodes. The NMAP procedure combined with a derived craniomaxillo-facial skeleton (CMFS) specific density-isotropic elastic modulus relationship was applied to produce specimen-specific FE models of 6 cadaveric heads. The NMAP procedure successfully generated models of the complex thin bone structures with surface elastic moduli reflective of cortical bone material properties. The specimen-specific CMFS FE models were able to accurately predict experimental strains measured under in vitro temporalis and masseter muscle loading (r=0.93, slope=1.01, n=5). The strength of this correlation represents a robust validation for CMFS FE modeling that can be used to better understand load transfer in this complex musculoskeletal system. The developed methodology offers a systematic process-flow able to address the complexity of the CMFS that can be further applied to create high-fidelity models of any musculoskeletal anatomy.
authors.affiliation: Sunnybrook Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
authors.forename: Amirreza
authors.initials: A
authors.lastname: Pakdel
authors.affiliation: Sunnybrook Research Institute, Toronto, ON, Canada; Department of Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Fialkov
authors.affiliation: Sunnybrook Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Department of Surgery, University of Toronto, Toronto, ON, Canada. Electronic address: cari.whyne@sunnybrook.ca.
authors.forename: Cari M
authors.initials: CM
authors.lastname: Whyne
mesh_terms: D016880:Anisotropy; D001842:Bone and Bones / Q000166:cytology / Q000000981:diagnostic imaging* / Q000502:physiology*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D066230:Patient-Specific Modeling; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing
keywords: Bone material property assignment; Craniomaxillofacial biomechanics; Finite element analysis; Partial volume correction; Thin bone modeling