Bone Densitometry and Osteoporosis

Osteoporosis occurs when bone loss is so severe that it lowers bone density and causes bones to become porous, brittle and likely to break. Reduced bone strength can lead to fractures resulting in a loss of mobility and independence. Osteoporosis and related bone disorders affect 27 million American women. While some bone loss can be expected as part of the normal aging process, osteoporosis is a dangerous disease. In fact, osteoporosis is often called the “silent disease” because it doesn’t produce symptoms until a fracture occurs. Increased awareness of osteoporosis has led to more advanced methods of diagnosing and monitoring the disease even before any symptoms are present. To assist in diagnosing low bone density, physicians may prescribe a Dual-energy X-ray Absorptiometry or DXA scan. This bone densitometry examination estimates the amount of bone mineral content in specific areas of the body, typically the spine and hip.

Here are some frequently asked questions and answers about bone density testing and DXA (Dual-energy X-ray Absorptiometry). For more information on osteoporosis and risk factors contact the National Osteoporosis Foundation www.nof.org.


What causes osteoporosis?
Why should I have a DXA scan?
How long will a DXA scan take?
Is a DXA scan safe?
How do I prepare for a DXA scan?
What is a DXA scan like?
When will I know the results of my scan?
Why is DXA the best method?
Is a bone density scan the same as a bone scan?
How is DXA different from VFA?
Will my insurance cover DXA?
Where does WRA perform DXA scans?


What causes osteoporosis?
Bone is living tissue that is constantly being broken down and reformed. As a person grows, bone forms faster than it breaks down until it reaches a peak bone mass between the ages of 25 and 35. After age 35, both men and women lose bone at a greater rate than it forms, causing bone loss. After menopause, women start to lose bone at a much more rapid rate than men of the same age. This rapid bone loss is usually due to a decrease in the production of the hormone, estrogen. As a greater amount of bone is lost, the bones become porous and brittle and much more susceptible to fracture. Early detection is the best way to prevent osteoporosis.




Why should I have a DXA scan?
Your physician will use the bone density information to decide if treatment for osteoporosis is needed. Whether or not treatment is prescribed, you may need a follow-up study at a later date to evaluate for possible progression of bone loss.




How long will a DXA scan take?
This examination lasts approximately 15 minutes.




Is a DXA scan safe?
The amount of radiation for a DXA scan is only a fraction of that received from a standard chest x-ray. It is comparable to the amount received on a transcontinental airline flight. The DXA method produces less radiation than other methods. Although DXA emits a very low amount of radiation, always inform the technologist if there is a chance that you are pregnant.




How do I prepare for a DXA scan?
Unless instructed otherwise, eat normally on the day of the exam; but avoid taking calcium supplements for at least 24 hours prior to your appointment. Wear loose, comfortable clothing. Sweat suits and other casual attire without zippers, buttons, grommets or any metal are preferred. You should not have had a barium study, radioisotope injection, or oral contrast material from a CT scan or MRI within seven days prior to your DXA study.




What is a DXA scan like?
A certified radiology technologist at Washington Radiology will conduct the exam. You will be asked to lie still on the scan table but you will be able to breathe normally throughout the procedure. A scanner (using a dual energy beam of very low dose x-rays) will pass over the lower spine/hip area. You will not feel anything during the exam. DXA technology works by measuring the amount of x-rays that are absorbed by the bones in your body. The two x-ray energies allow the machine to differentiate between bone and soft tissue, giving a very accurate estimation of bone density. The radiologist will produce a report for your physician based on the bone density measurements and your medical history.




When will I know the results of my scan?
At WRA, a board-certified radiologist will interpret your scan on the same day of your test. He/she will record the findings in a report which will be sent to your physician. If necessary or requested, the radiologist will call your physician right away. Your physician will then share the results with you.




Why is DXA the best method?
DXA scanning has been proven to be the most accurate method of measuring bone density; it uses the least amount of radiation, and is lower in cost than other methods.




Is a bone density scan the same as a bone scan?
No. Although the two are often confused because they sound alike, they are completely different. A bone scan is a nuclear medicine study used to determine other elements of bone health such as hairline fractures and cancerous deposits. It does not determine bone density.




How is DXA different than VFA?
A VFA or Vertebral Fracture Assessment is a 10-second x-ray of the spine, taken in combination with DXA. With VFA, doctors can see existing vertebral (spine) fractures, which may indicate the need for more aggressive treatment, even if the DXA bone density results are in the “normal” range. Not all patients need a VFA. However, using VFA—when clinically indicated—can be beneficial in assessing bone health.




Will my insurance cover DXA?
DXA is covered under most insurance plans. Medicare covers biannual screening DXA exams, and more frequently if medically indicated. Always check with your insurance carrier to determine your specific coverage.




Where does WRA perform DEXA scans?
DEXA scans are performed at our Sterling, Fairfax, Bethesda, Chevy Chase/Friendship Heights and 2141 K Street offices.