TY - JOUR
T1 - Development of subject-specific and statistical shape models of the knee using an efficient segmentation and mesh-morphing approach
AU - Baldwin, Mark A.
AU - Langenderfer, Joseph E.
AU - Rullkoetter, Paul J.
AU - Laz, Peter J.
N1 - Funding Information:
The authors would like to thank Dr. Lorin Maletsky and Chadd Clary at the University of Kansas for providing image data. The authors acknowledge the assistance of Cameron Lemmon and Rakesh Ramachandran with segmentation. This research was supported in part by DePuy, a Johnson & Johnson Company.
PY - 2010/3
Y1 - 2010/3
N2 - Subject-specific finite element models developed from imaging data provide functional representation of anatomical structures and have been used to evaluate healthy and pathologic knee mechanics. The creation of subject-specific models is a time-consuming process when considering manual segmentation and hexahedral (hex) meshing of the articular surfaces to ensure accurate contact assessment. Previous studies have emphasized automated mesh mapping to bone geometry from computed tomography (CT) scans, but have not considered cartilage and soft tissue structures. Statistical shape modeling has been proposed as an alternative approach to develop a population of subject models, but still requires manual segmentation and registration of a training set. Accordingly, the aim of the current study was to develop an efficient, integrated mesh-morphing-based segmentation approach to create hex meshes of subject-specific geometries from scan data, to apply the approach to natural femoral, tibial, and patellar cartilage from magnetic resonance (MR) images, and to demonstrate the creation of a statistical shape model of the knee characterizing the modes of variation using principal component analysis. The platform was demonstrated on MR scans from 10 knees and enabled hex mesh generation of the knee articular structures in approximately 1.5 h per subject. In a subset of geometries, average root mean square geometric differences were 0.54 mm for all structures and in quasi-static analyses over a range of flexion angles, differences in predicted peak contact pressures were less than 5.3% between the semi-automated and manually generated models. The integrated segmentation, mesh-morphing approach was employed in the efficient development of subject-specific models and a statistical shape model, where populations of subject-specific models have application to implant design evaluation or surgical planning.
AB - Subject-specific finite element models developed from imaging data provide functional representation of anatomical structures and have been used to evaluate healthy and pathologic knee mechanics. The creation of subject-specific models is a time-consuming process when considering manual segmentation and hexahedral (hex) meshing of the articular surfaces to ensure accurate contact assessment. Previous studies have emphasized automated mesh mapping to bone geometry from computed tomography (CT) scans, but have not considered cartilage and soft tissue structures. Statistical shape modeling has been proposed as an alternative approach to develop a population of subject models, but still requires manual segmentation and registration of a training set. Accordingly, the aim of the current study was to develop an efficient, integrated mesh-morphing-based segmentation approach to create hex meshes of subject-specific geometries from scan data, to apply the approach to natural femoral, tibial, and patellar cartilage from magnetic resonance (MR) images, and to demonstrate the creation of a statistical shape model of the knee characterizing the modes of variation using principal component analysis. The platform was demonstrated on MR scans from 10 knees and enabled hex mesh generation of the knee articular structures in approximately 1.5 h per subject. In a subset of geometries, average root mean square geometric differences were 0.54 mm for all structures and in quasi-static analyses over a range of flexion angles, differences in predicted peak contact pressures were less than 5.3% between the semi-automated and manually generated models. The integrated segmentation, mesh-morphing approach was employed in the efficient development of subject-specific models and a statistical shape model, where populations of subject-specific models have application to implant design evaluation or surgical planning.
KW - Articular cartilage
KW - Finite element
KW - Knee mechanics
KW - Mesh morphing
KW - Segmentation
KW - Statistical shape model
KW - Subject-specific model
UR - http://www.scopus.com/inward/record.url?scp=76749151340&partnerID=8YFLogxK
U2 - 10.1016/j.cmpb.2009.07.005
DO - 10.1016/j.cmpb.2009.07.005
M3 - Article
C2 - 19695732
AN - SCOPUS:76749151340
SN - 0169-2607
VL - 97
SP - 232
EP - 240
JO - Computer Methods and Programs in Biomedicine
JF - Computer Methods and Programs in Biomedicine
IS - 3
ER -