Spatio-temporal atlas of bone mineral density ageing

Osteoporosis is an age-associated bone disease characterised by low bone mass. An improved understanding of the underlying mechanism for age-related bone loss could lead to enhanced preventive and therapeutic strategies for osteoporosis. In this work, we propose a fully automatic pipeline for developing a spatio-temporal atlas of ageing bone. Bone maps are collected using a dual-energy X-ray absorptiometry (DXA) scanner. Each scan is then warped into a reference template to eliminate morphological variation and establish a correspondence between pixel coordinates. Pixel-wise bone density evolution with ageing was modelled using smooth quantile curves. To construct the atlas, we amalgamated a cohort of 1714 Caucasian women (20–87 years) from five different centres in North Western Europe. As a systematic difference exists between different DXA manufacturers, we propose a novel calibration technique to homogenise bone density measurements across the centres. This technique utilises an alternating minimisation technique to map the observed bone density measurements into a latent standardised space. To the best of our knowledge, this is the first spatio-temporal atlas of ageing bone.