DEXA scan (DEXS)

DEXA Scan (DEXS)

A DEXA scan (DEXS), or dual-energy X-ray absorptiometry scan, is a medical imaging technique primarily used to measure bone mineral density (BMD). It is a non-invasive procedure that helps diagnose conditions like osteoporosis and assess fracture risk.

What to Expect During a DEXA Scan

1. Procedure: During the scan, the patient lies on a padded table while a scanning arm passes over their body. The scan typically focuses on the lower spine and hips, which are common sites for osteoporosis-related fractures. The process is quick, usually taking about 10 to 20 minutes.
2. Radiation Exposure: DEXA scans use a very low dose of ionizing radiation, significantly less than traditional X-rays. This minimal exposure makes it a safe option for most patients, although it is not recommended for pregnant women due to potential risks to the fetus.
3. Preparation: No special preparation is usually required. Patients may be asked to wear loose clothing without metal fasteners, as metal can interfere with the imaging results.
4. Scoring System: After the scan, results are provided in the form of T-scores and Z-scores:

• T-score: Compares the patient’s bone density to that of a healthy young adult.
• Z-score: Compares the patient’s bone density to that of individuals of the same age, gender, and ethnicity. The World Health Organization classifies T-scores as follows:
• Above -1 SD: Normal bone density
• Between -1 and -2.5 SD: Osteopenia (mildly reduced bone density)
• At or below -2.5 SD: Osteoporosis

Clinical Significance

1. Diagnosis of Osteoporosis: DEXA scans are essential for diagnosing osteoporosis, particularly in individuals at higher risk due to age, gender (especially postmenopausal women), family history, or previous fractures.
2. Monitoring Treatment: These scans can also be used to monitor changes in bone density over time, helping healthcare providers assess the effectiveness of osteoporosis treatments.
3. Fracture Risk Assessment: By evaluating bone density, DEXA scans help predict an individual’s risk of future fractures, allowing for timely interventions.

Benefits and Risks

• Benefits:
• Non-invasive and quick procedure.
• Provides accurate measurements of bone density.
• Helps in early detection and management of osteoporosis.
• Risks:
• Very low radiation exposure, comparable to natural background radiation.
• Potential slight increase in cancer risk from ionizing radiation, though minimal compared to other imaging techniques.

Conclusion

DEXA scans are a vital tool in assessing bone health and diagnosing osteoporosis. By providing precise measurements of bone density, they enable healthcare providers to make informed decisions regarding prevention and treatment strategies for maintaining bone health.

References

1. NHS. (2022). Bone density scan (DEXA scan). Retrieved from NHS
2. CDC. (2023). Facts About Bone Density (DEXA Scan). Retrieved from CDC
3. RadiologyInfo.org. (n.d.). Bone Density Scan (DEXA or DXA). Retrieved from RadiologyInfo
4. Bangkok International Hospital. (n.d.). ตรวจความหนาแน่นกระดูกกับ DXA SCAN. Retrieved from Bangkok International Hospital