Bone Mineral Density
Ultrasound is a screening test that is
sometimes offered at events such as health fairs. It is only used to look for problems. If results from an ultrasound test find
low bone density, DEXA is recommended to confirm the results. Ultrasound uses
sound waves to measure BMD, usually in your heel. Ultrasound is quick,
painless, and does not use potentially harmful radiation like X-rays. One
disadvantage of ultrasound is it can't measure the density of the bones most
likely to fracture from osteoporosis (the hip and spine). Ultrasound is not used to
keep track of how well medicine for osteoporosis is working.
Before being screened for osteoporosis, you may want to
think about what you will do if the tests show you have a high chance of
getting osteoporosis. For more information, see:
Osteoporosis: Should I Have a Dual-Energy X-Ray Absorptiometry (DEXA) Test?
Health Tools help you make wise health decisions or take action to improve your health.
Decision Points focus on key medical care decisions that are important to many health problems.
Osteoporosis: Should I Have a Dual X-Ray Absorptiometry (DEXA) Test?
Why It Is Done
A bone mineral density (BMD) test is
- All women who are age
65 or older, and younger women who are at increased risk for broken bones caused by osteoporosis.1
- Older men, and men with other risk factors for
- Men and women who have
- Men and women who
have been taking
corticosteroids, such as prednisone, for a long
- Follow-up of how well treatment for osteoporosis is working
for men and women being treated for 2 years or longer.
How To Prepare
Avoid wearing clothes with metal buttons
or buckles for the test. You also may want to remove any jewelry that might
interfere with the scan, such as a bracelet if you are having the scan done on
How It Is Done
A bone mineral density (BMD) scan is usually
done in the special radiology department or clinic by a technologist.
Peripheral dual-energy X-ray absorptiometry (P-DEXA) machines are portable
units that can be used in a doctor's office.
You will need to lie
on your back on a padded table. You can usually leave your clothes on. You may
need to lie with your legs straight or with your lower legs resting on a
platform built into the table.
The machine will scan your bones
and measure the amount of radiation they absorb. The DEXA technique, which
scans the hip and lower spine, takes about 20 minutes to perform. Other
techniques may take 30 to 45 minutes.
Portable machines (P-DEXA)
can measure bone density in the wrist or forearm.
Testing at least two different bones
(preferably the hip and spine) each time is the most reliable way of measuring
BMD. It is best to test the same bones and to use the same measurement
technique and BMD equipment each time.