Dual energy x ray absorptiometry DXA or DEXA; measuring bone mineral density BMD

Описание: 🩻 Dual-Energy X-Ray Absorptiometry (DEXA / DXA)
Dual-energy X-ray absorptiometry (DEXA or DXA) is a specialized imaging technique primarily used to measure bone mineral density (BMD). It is considered the gold standard for diagnosing osteoporosis and assessing fracture risk.

🔎 How It Works
Dual-energy principle: Uses two X-ray beams of different energy levels.

Absorption differences: Bones and soft tissues absorb X-rays differently; by comparing absorption at two energy levels, the scanner isolates bone density.

Output: Provides a precise measurement of bone mineral density in grams per square centimeter (g/cm²).

🩺 Clinical Applications in Orthopedics
Osteoporosis diagnosis: Detects reduced bone density before fractures occur.

Fracture risk assessment: Helps predict risk of hip, spine, and wrist fractures.

Monitoring treatment: Tracks effectiveness of osteoporosis therapies (e.g., bisphosphonates, hormone therapy).

Pre-surgical evaluation: Assesses bone quality before orthopedic procedures like joint replacement or spinal surgery.

Pediatric orthopedics: Occasionally used to evaluate bone health in children with chronic conditions affecting growth.

📊 Key Measurements
T-score: Compares patient’s BMD to that of a healthy young adult.

Normal: ≥ -1

Osteopenia: -1 to -2.5

Osteoporosis: ≤ -2.5

Z-score: Compares patient’s BMD to age- and sex-matched norms (useful in children and younger adults).

✅ Advantages
Non-invasive, quick (10–20 minutes).

Very low radiation exposure (much lower than a chest X-ray).

High accuracy and reproducibility.

⚠️ Limitations
Does not assess bone quality (microarchitecture, strength).

Artifacts (spinal deformities, calcifications, surgical implants) can affect accuracy.

Population-specific reference ranges may vary, so interpretation requires clinical context

#bonedensity