DT-MRI based computation of collagen fiber deformation in human articular cartilage: a feasibility study.
Accurate techniques for simulating the deformation of soft biological tissues are an increasingly valuable tool in many areas of biomechanical analysis and medical image computing. To model the complex morphology and response of articular cartilage, a hyperviscoelastic (dispersed) fiber-reinforced constitutive model is employed to complete two specimen-specific finite element (FE) simulations of an indentation experiment, with and without considering fiber dispersion. Ultra-high field Diffusion Tensor Magnetic Resonance Imaging (17.6 T DT-MRI) is performed on a specimen of human articular cartilage before and after indentation to approximately 20% compression. Based on this DT-MRI data, we detail a novel FE approach to determine the geometry (edge detection from first eigenvalue), the meshing (semi-automated smoothing of DTI measurement voxels), and the fiber structural input (estimated principal fiber direction and dispersion). The global and fiber fabric deformations of both the un-dispersed and dispersed fiber models provide a satisfactory match to that estimated experimentally. In both simulations, the fiber fabric in the superficial and middle zones becomes more aligned with the articular surface, although the dispersed model appears more consistent with the literature. In the future, a multi-disciplinary combination of DT-MRI and numerical simulation will allow the functional state of articular cartilage to be determined in vivo.
Institute of Biomechanics, Center of Biomedical Engineering, Graz University of Technology, Kronesgasse 5-I, Graz, Austria.
David M
DM
Pierce
Werner
W
Trobin
José G
JG
Raya
Siegfried
S
Trattnig
Horst
H
Bischof
Christian
C
Glaser
Gerhard A
GA
Holzapfel
D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology / Q000473:pathology / Q000502:physiology; D003094:Collagen / Q000032:analysis*; D038524:Diffusion Magnetic Resonance Imaging; D005109:Extracellular Matrix; D005240:Feasibility Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male
D003094:Collagen