DEXA scan

DEXA (Dual-Energy X-ray Absorptiometry) is a high-precision medical imaging scan used to measure Bone Mineral Density (BMD) and analyze body composition. It is recognized as the "gold standard" for diagnosing osteoporosis and assessing fracture risk. Beyond bone health, modern DEXA scans provide a detailed breakdown of tissue distribution, including lean muscle mass and visceral adipose tissue (VAT)—the deep belly fat linked to metabolic disease. Unlike a standard X-ray, which captures structural images, DEXA quantifies the actual mineral and tissue content of the body.

The scan works by emitting two distinct X-ray beams with different energy levels. One beam is primarily absorbed by soft tissues (fat and muscle), while the other is absorbed by bone. As these beams pass through the body, a detector calculates the amount of energy that makes it through. By comparing the absorption rates, the system can mathematically distinguish between bone, lean mass, and fat mass. The results for bone health are typically presented as a T-score (comparing your bone density to a healthy young adult) and a Z-score (comparing your density to peers of the same age and sex).

Based on 2024-2025 USPSTF and ISCD guidelines:

• Women 65+: Universal screening is recommended for all women in this age group.
• Postmenopausal Women <65: Screening is recommended for those with clinical risk factors, such as a family history of hip fractures, smoking, low body weight, or long-term corticosteroid use.
• Men: While universal screening is not yet mandated, it is often recommended for men over 70 or those with high-risk conditions (e.g., hypogonadism or significant height loss).
• Body Composition: For athletes or those managing metabolic health, scans every 3–6 months are effective for tracking muscle gain or visceral fat loss.
• Safety & Prep: Avoid calcium supplements for 24 hours before your scan. Ensure you are well-hydrated for body composition accuracy. Contraindications: Do not have a DEXA scan if you are pregnant or have received contrast dye (like barium) within the last 7 days.