Bone densitometry, also called dual-energy X-ray absorptiometry or DEXA, is commonly used to diagnose osteoporosis and to assess an individual’s risk for developing fractures. A DEXA scan is simple, quick and non-invasive. It’s also the most accurate method for diagnosing osteoporosis. It uses a very small dose of ionizing radiation to produce pictures of the inside of the body (usually the lower spine and hips) to measure bone loss. DEXAs are also effective in tracking the effects of treatment for osteoporosis and other conditions that cause bone loss.
This outpatient exam requires little to no special preparation. Tell your doctor and the technologist if there is a possibility you are pregnant or if you recently had a barium exam or received an injection of contrast material for a CT or radioisotope scan. Leave jewelry at home and wear loose, comfortable clothing. You may be asked to wear a gown. You should not take calcium supplements for at least 24 hours before your exam. The Central DEXA devices measure bone density in the hip and spine and are usually located in hospitals and medical offices. Central devices have a large, flat table and an “arm” suspended overhead.
In addition to a DEXA scan, a Vertebral Fracture Assessment (VFA), an examination of the spine to screen for vertebral fractures that is performed on the DEXA machine, may be recommended for older patients, especially if they have lost more than two inches of height, have unexplained back pain, or if a DEXA scan gives borderline readings.
The DEXA bone density test is usually completed within 10 to 30 minutes, depending on the equipment used and the parts of the body being examined. The VFA test adds only a few minutes to the DEXA procedure.
The DEXA scan can also assess an individual’s risk for developing fractures. The risk of fracture is affected by age, body weight, history of prior fracture, family history of osteoporotic fractures and lifestyle issues such as cigarette smoking and excessive alcohol consumption. These factors are taken into consideration when deciding if a patient needs therapy.
You will probably be asked to fill out a questionnaire that will help the doctor determine if you have medical conditions or take certain medications that either increase or decrease your risk of a fracture. The World Health Organization has recently released an online survey that combines the DEXA results and a few basic questions and can be used to predict 10-year hip fracture risk for post-menopausal women.
Your results will be in the form of a T score which compares your bone density to a healthy 30-year-old, and is meant for ages 50 and older. A score above -1 is considered normal. A score between -1 and -2.5 is classified as osteopenia (low bone mass). A score below -2.5 is defined as osteoporosis.
If you have risk factors for osteoporosis or concerns over your bone health, ask your doctor or health care provider about a referral to see Bone Health Specialist DeeAnna Kenny, P.A.-C., at MidMichigan Health’s Bone Health Clinic. For more information, call the Clinic at (989) 837-9192.