Image Modalities Practice Test

Bone densitometry quantifies bone mineral content and density at defined skeletal sites rather than giving a single value for the entire skeleton. In practice, measurements are taken at sites most predictive of fracture risk and representative of different bone types—most commonly the lumbar spine and proximal hip—because these areas are where osteoporosis-related fractures occur most often and where density changes correlate well with fracture risk. Some devices can also measure at the forearm or provide a total-body assessment, but densities of the skull or jaw are not used for standard osteoporosis evaluation since they don’t track fracture risk in the common sites. So, densitometry targets specific skeletal sites across the body rather than measuring everywhere at once.