Diagnostic imaging of osteoporosis and sarcopenia: a narrative review.

Osteoporosis and sarcopenia represent two major health problems with an increasing prevalence in the elderly population. The correlation between these diseases has been widely reported, leading to the development of the term "osteosarcopenia" to diagnose those patients suffering from both diseases. Several imaging methods for the diagnosis and management of osteoporosis exist, with dual-energy X-ray absorptiometry (DXA) being the most commonly used for measuring bone mineral density (BMD). Imaging technique other than DXA is represented by conventional radiography, computed tomography (CT) and ultrasound (US). Similarly, the imaging technologies used to detect loss of skeletal muscle mass in sarcopenia include DXA, CT, US and magnetic resonance imaging (MRI). These methods differ in terms of reliability, radiation exposure and costs. CT and MRI represent the gold standard for evaluating body composition (BC), but are costly and time-consuming. DXA remains the most often used technology for studying BC, being quick, widely available and with low radiation exposure.