Radiology of Osteoporosis

The radiologist has a number of roles not only in diagnosing but also in treating osteoporosis. Radiologists diagnose fragility fractures with all imaging modalities, which includes magnetic resonance imaging (MRI) demonstrating radiologically occult insufficiency fractures, but also lateral chest radiographs showing asymptomatic vertebral fractures. In particular MRI fragility fractures may have a nonspecific appearance and the radiologists needs to be familiar with the typical locations and findings, to differentiate these fractures from neoplastic lesions. It should be noted that radiologists do not simply need to diagnose fractures related to osteoporosis but also to diagnose those fractures which are complications of osteoporosis related pharmacotherapy. In addition to using standard radiological techniques radiologists also use dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT) to quantitatively assess bone mineral density for diagnosing osteoporosis or osteopenia as well as to monitor therapy. DXA measurements of the femoral neck are also used to calculate osteoporotic fracture risk based on the Fracture Risk Assessment Tool (FRAX) score, which is universally available. Some of the new technologies such as high-resolution peripheral computed tomography (HR-pQCT) and MR spectroscopy allow assessment of bone architecture and bone marrow composition to characterize fracture risk. Finally radiologists are also involved in the therapy of osteoporotic fractures by using vertebroplasty, kyphoplasty, and sacroplasty. This review article will focus on standard techniques and new concepts in diagnosing and managing osteoporosis.