Bone Mineral Density (BMD) Measurement
Assessing Your Risk for Spinal Fracture and Osteoporosis
A bone mineral density (BMD) test measures skeletal bone loss. The amount of bone lost tells your physician how dense and strong your bones are. The test is performed to help diagnose your risk of fracture (eg, spinal compression fracture), detect osteopenia (low bone density) and osteoporosis. Furthermore, the test results can help your physician evaluate the effectiveness of treatment for osteoporosis.
Bone densitometry may include your FRAX® score. FRAX is a fracture risk assessment tool (computer software) that reviews a patient's age, bone density and other fracture risk factors.
The radiologist reviews all your test results, writes a report and sends it to your ordering physician.
Other names for a bone mineral density test include:
- Bone density scan
- Bone densitrometry
- Dual energy x-ray absorptiometry (DXA or DEXA)
Your doctor may order bone mineral density testing if:
- You are a woman who went through menopause before age 45 and/or are not taking estrogen (eg, hormone replacement therapy).
- You are a man with testosterone deficiency.
- You have hyperthyroidism, hyperparathyroidism, type 1 diabetes, liver or kidney disease, or rheumatoid arthritis.
- You take certain medications (eg, corticosteroids) that can cause loss of bone density.
- X-ray, CT scan or MRI results indicated osteopenia or osteoporosis.
- Previous fracture(s) (eg, spine, hip).
- Maternal family history of hip or spine fracture.
About Bone Densitometry
The test is performed on an outpatient basis at the hospital or radiology facility. The test is easy, takes less than 15 minutes, painless and noninvasive. Bone densitometry may include a Lateral Vertebral Assessment to check for spinal fracture due to loss of height (eg, one inch or more) or borderline bone density results.
Preparing for Bone Mineral Density Testing
- Tell your doctor and/or radiologist if you are or could be pregnant.
- In advance of your test date, your doctor will tell you which, if any medications to stop (and when).
- Do not take calcium supplements 24-hour prior to the test.
- You do not need to fast.
- You can drive yourself to and from the testing facility.
At the testing facility, you may be asked to change into a gown and remove metal items, such as jewelry. The radiology technician positions you laying on your back on the DEXA scanner's padded table. The test is usually performed in two steps:
- Step 1—Spine: You bend your knees and a triangular-shaped pillow is slipped beneath.
- Step 2—Hip: One foot is gently rotated inward and held in place.
During each step, the scanner portion of the machine moves over your body. The entire test usually takes less than 15 minutes.
Radiological Society of North America, Inc. (RSNA). Bone Densitometry. February 12, 2014. http://www.radiologyinfo.org/en/info.cfm?pg=dexa. Accessed February 12, 2015.