Bone imaging: traditional techniques and their interpretation.

Patients with osteoporosis have to be diagnosed at an early stage to prevent fractures, the worst complication of this disease. Currently, measurements of bone mineral density (BMD) are used most frequently in the diagnosis of osteoporosis. According to the World Health Organization, osteoporosis is defined on the basis of BMD measurements that are compared with those of a healthy, young, female population. The best established techniques to measure BMD are dual x-ray absorptiometry of the lumbar spine and proximal femur and quantitative computed tomography of the lumbar spine. Conventional radiographs are not suited to assess bone mass, but they are important in the diagnosis and differential diagnosis of osteoporotic fractures. Quantitative ultrasound and structure analysis, based on high-resolution magnetic resonance imaging and computed tomography, are newer techniques in the diagnosis of osteoporosis that also focus on the assessment of bone structure.