Reconstructing the 3D Shape and Bone Mineral Density Distribution of the Proximal Femur From Dual-Energy X-Ray Absorptiometry

Abstract—The accurate diagnosis of osteoporosis has gained in-creasing importance due to the aging of our society. Areal bone mineral density (BMD) measured by dual-energy X-ray absorp-tiometry (DXA) is an established criterion in the diagnosis of os-teoporosis. This measure, however, is limited by its two-dimen-sionality. This work presents a method to reconstruct both the 3D bone shape and 3DBMDdistribution of the proximal femur from a single DXA image used in clinical routine. A statistical model of the combined shape and BMD distribution is presented, together with a method for its construction from a set of quantitative computed tomography (QCT) scans. A reconstruction is acquired in an inten-sity based 3D-2D registration process whereby an instance of the model is found that maximizes the similarity between its projection and the DXA image. Reconstruction experiments were performed on the DXA images of 30 subjects, with a model constructed fro