Appendicular and vertebral bone mass in ankylosing spondylitis. A comparison of plain radiographs with single‐ and dual‐photon absorptiometry and with quantitative computed tomography

Abstract

Male patients with AS have axial osteopenia. In those who have very severe AS with new bone formation, DPA demonstrates normal values as a result of two opposite trends: central osteopenia (as assessed from QCT) and peripheral new-bone formation, which transforms vertebral bodies into long bones. This could modify the mechanical resistance of the spine and account for the propensity for anteroposterior transvertebral and transdiscal fractures after trauma in AS.