What imaging modality is commonly used as the gold standard for measuring bone mineral density?

• A. CT scan
• B. DEXA
• C. MRI
• D. X-ray

Answer: (B)

The gold standard for measuring bone mineral density is Dual-Energy X-ray Absorptiometry (DEXA). This imaging modality is specifically designed to assess bone density and is highly sensitive in detecting even small changes in bone mineral content. DEXA operates by utilizing two different X-ray energies to differentiate between bone and soft tissue, allowing for precise calculations of bone density.

The accuracy and reliability of DEXA make it the preferred choice for osteoporosis diagnosis and management, as it provides crucial data that help in assessing fracture risk and monitoring treatment efficacy. Additionally, DEXA has low radiation exposure compared to other imaging techniques, which enhances its safety profile for patients needing repeated assessments.

While other modalities, like CT scans and MRIs, provide valuable information about bone structure and health, they are not primarily designed for measuring bone mineral density. Regular X-rays can offer some insights into bone health, but they lack the quantifiable precision of DEXA when it comes to assessing mineral density. Thus, DEXA remains the established standard for evaluating bone health.