Which imaging modality is best for initial osteoporosis screening?

• A. Ultrasound of calcaneus
• B. DEXA scanning of the hip and spine
• C. CT scan of the chest
• D. MRI of the spine

Answer: (B)

DEXA scanning of the hip and spine is the best initial test for osteoporosis screening. It measures bone mineral density at sites most predictive of fracture risk and provides a quantitative result (T-score) used to diagnose osteoporosis and assess risk. The hip and spine sites are prioritized because fractures there cause the most morbidity and the BMD at these sites correlates most strongly with overall fracture risk, making it the most clinically useful screening measure.

Ultrasound of the calcaneus is noninvasive but peripheral bone density at the heel doesn’t predict hip or vertebral fractures as reliably, so it’s not the preferred screening tool. CT can assess bone density but involves higher radiation and is not practical or cost-effective for routine screening. MRI does not measure bone density in a way that’s useful for screening osteoporosis.