Dual-energy X-ray absorptiometry (DEXA) is an imaging technology that uses a very low amount of X-ray energy to detect the presence of osteoporosis. Osteoporosis is a disease that gradually weakens bones, leading to bone fragility and an increased chance of fractures to the spine, hips and wrists. DEXA scanning can identify low bone density in patients at an early stage, enabling doctors to prescribe appropriate treatment before the condition worsens. Images of the lower spine and hips are most often used in checking for osteoporosis. As with other diseases and conditions, early detection is the key to prevention of further bone loss and eventual fractures.
While the disease affects both men and women, 80% of those affected are women. In fact, 22 million American women are affected by osteoporosis. Women have a higher risk for osteoporosis than men because women often have smaller, thinner frames. In addition, menopause causes women to produce less estrogen, a hormone that helps protect them against bone loss; 20% of bone mass can be lost in the 5-7 years following menopause.
Other factors that may add to the risk of osteoporosis include:
- Advanced age
- History of bone fracture
- Family history of osteoporosis
- Low calcium diet
- Lack of exercise
- Eating disorders
- Abnormal absence of menstrual periods
- Certain medicine, such as steroids and anticonvulsants
- Alcohol or tobacco use
- DEXA scanning is noninvasive and painless.
- DEXA bone density testing is the most accurate method available for the diagnosis of osteoporosis. It is also considered an accurate estimator of fracture risk. It will not tell whether you will or will not have a fracture, but gives relative risk of suffering a fracture. As with other diseases and conditions, early detection is the key to prevention of further bone loss and eventual fractures.
- No complications are expected with the DEXA procedure.
How should I prepare for the procedure?
You should not take any calcium supplements the morning of your exam. Wear comfortable clothing that has no metal zippers or buttons in the abdominal or pelvic areas. If you do not have clothing without metal components, we may ask you to change into a gown. You may also be asked to remove jewelry, eyeglasses and any metal objects or clothing that might interfere with the x-ray images. If you have recently undergone a barium study of any kind -such as an upper gastrointestinal (UGI) tract exam, barium enema or computed tomography (CT) scan -you should wait at least 14 days before a DEXA exam is performed. That waiting period is important to prevent any residual barium from interfering with your DEXA exam. Please let us know before your exam begins if you may be pregnant.
How is the procedure performed?
You will be asked to lie on your back on a padded table while a movable arm passes over your body. A technician will remain with you and you will feel no sensations from the exam, which typically takes 15 to 30 minutes. DEXA examinations are painless, fast and easy.