Osteoporosis International

, Volume 20, Issue 3, pp 455–461

Generation of a 3D proximal femur shape from a single projection 2D radiographic image

Original Article

DOI: 10.1007/s00198-008-0665-4

Cite this article as:
Langton, C.M., Pisharody, S. & Keyak, J.H. Osteoporos Int (2009) 20: 455. doi:10.1007/s00198-008-0665-4

Abstract

Summary

Generalized Procrustes analysis and thin plate splines were employed to create an average 3D shape template of the proximal femur that was warped to the size and shape of a single 2D radiographic image of a subject. Mean absolute depth errors are comparable with previous approaches utilising multiple 2D input projections.

Introduction

Several approaches have been adopted to derive volumetric density (g cm-3) from a conventional 2D representation of areal bone mineral density (BMD, g cm-2). Such approaches have generally aimed at deriving an average depth across the areal projection rather than creating a formal 3D shape of the bone.

Methods

Generalized Procrustes analysis and thin plate splines were employed to create an average 3D shape template of the proximal femur that was subsequently warped to suit the size and shape of a single 2D radiographic image of a subject. CT scans of excised human femora, 18 and 24 scanned at pixel resolutions of 1.08 mm and 0.674 mm, respectively, were equally split into training (created 3D shape template) and test cohorts.

Results

The mean absolute depth errors of 3.4 mm and 1.73 mm, respectively, for the two CT pixel sizes are comparable with previous approaches based upon multiple 2D input projections.

Conclusions

This technique has the potential to derive volumetric density from BMD and to facilitate 3D finite element analysis for prediction of the mechanical integrity of the proximal femur. It may further be applied to other anatomical bone sites such as the distal radius and lumbar spine.

Keywords

Geometric morphometricsProximal femurThree-dimensional shapeVolumetric density

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2008

Authors and Affiliations

  1. 1.Centre for Metabolic Bone DiseaseHull Royal InfirmaryHullUK
  2. 2.Postgraduate Medical InstituteUniversity of HullHullUK
  3. 3.Department of Computer ScienceUniversity of HullHullUK
  4. 4.Department of Orthopaedic SurgeryUniversity of CaliforniaIrvineUSA
  5. 5.Medical PhysicsQueensland University of TechnologyBrisbaneAustralia