title: On the use of laser scans to validate reverse engineering of bony anatomy.
abstract: There is a growing body of evidence to suggest the arthritic hip is an irregularly-shaped, aspherical joint, especially in severely pathological cases. Current methods used to study the shape and motion of the hip in-vivo, are invasive and impractical. This study aimed to assess whether a plastic model of the hip joint can be accurately made from a pelvic CT scan. A cadaver hemi-pelvis was CT imaged and segmented from which a 3D plastic model of the proximal femur and hemi-pelvis were fabricated using rapid-prototyping. Both the plastic model and the cadaver were then imaged using a high-resolution laser scanner. A three-way shape analysis was performed to compare the goodness-of-fit between the cadaver, image segmentation, and the plastic model. Overall, we obtained sub-millimeter fit accuracy between all three hip representations. Shape fit was least favorable in areas where the boundary between cartilage and bone is difficult to distinguish. We submit that rapid-prototyping is an accurate and efficient mechanism for obtaining 3D specimens as a means to further study the irregular geometry of the hip.
authors.affiliation: School of Computing, Queen's University, Kingston, Ontario, Canada K7L3N6.
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Anstey
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Smith
authors.forename: Brian
authors.initials: B
authors.lastname: Rasquinha
authors.forename: John F
authors.initials: JF
authors.lastname: Rudan
authors.forename: Randy E
authors.initials: RE
authors.lastname: Ellis
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D002102:Cadaver; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007834:Lasers; D008953:Models, Anatomic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed