Diagnosing osteoporosis with DEXA.

DEXA bone densitometry is most often used to diagnose osteoporosis, a condition that often affects women after menopause but may also be found in men. Osteoporosis involves a gradual loss of calcium, causing the bones to become thinner, more fragile and more likely to break. The DEXA test can also assess your risk for developing fractures. If your bone density is found to be low, you and your physician can work together on a treatment plan to help prevent fractures before they occur. DEXA is also effective in tracking the effects of treatment for osteoporosis or for other conditions that cause bone loss. Bone density testing is strongly recommended if you:

• are a post-menopausal woman and not taking estrogen.
• have a personal or maternal history of hip fracture or smoking.
• are a post-menopausal woman who is tall (over 5 feet 7 inches) or thin (less than 125 pounds).
• are a man with clinical conditions associated with bone loss.
• use medications that are known to cause bone loss, including corticosteroids such as Prednisone, various anti-seizure medications such as Dilantin and certain barbiturates, or high-dose thyroid replacement drugs.
• have type 1 (formerly called juvenile or insulin-dependent) diabetes, liver disease, kidney disease or a family history of osteoporosis.
• have high bone turnover, which shows up in the form of excessive collagen in urine samples.
• have a thyroid condition, such as hyperthyroidism.
• have experienced a fracture after only mild trauma.
• have had x-ray evidence of vertebral fracture or other signs of osteoporosis.

On the day of the exam eat normally, but don't take calcium supplements for at least 24 hours beforehand. Wear loose, comfortable clothing, avoiding garments that have zippers, belts or buttons made of metal.

Inform your physician if you recently had a barium examination or have been injected with a contrast material for a computed tomography (CT) scan or radioisotope scan; you may have to wait 10 to 14 days before undergoing a DEXA test. Women should always inform their physician or x-ray technologist if there is a possibility they are pregnant.