What is DEXA Bone Densitometry and how does it work?
DEXA stands for “Dual Energy X-ray Absorptiometry.” It is the most widely used technique for measuring bone mineral density (BMD) and diagnosing the presence of osteoporosis. This measurement is accomplished by computer analysis of the difference in absorption of X-ray beams of two differing energies, that have been passed through the spine and hips. (The spine and hips are examined, because bones in these areas bear a great deal of stress, and because fractures in the spine and hip are among the most disabling when they occur.) The test result is reported as a “T-score” – which compares a patient’s bone mineral density to that of a healthy young person.

What is Osteoporosis?
Osteoporosis is defined by the World Health Organization as abnormally low bone mineral density (BMD), with a T-score of –2.5 or less. This means that bone mineral density has dropped to a dangerous level when bones have weakened so much that the chance of a fracture occurring, even with minimal trauma, is significantly increased. It is common to gradually lose bone strength after the age of 30, and osteoporosis is unfortunately very common in older individuals, especially women.

When is Bone Densitometry used?
Bone densitometry is usually indicated for women who are over age 65, are considering starting or stopping hormone replacement therapy, or are menopausal/perimenopausal with any risk factors.

Bone densitometry 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 (0ver 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 (formally 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

Other risk factors that have to do with your heredity and lifestyle include:
Family history of osteoporosis or fractures caused by osteoporosis, such as hip fractures, wrist fractures, loss of height, dowager’s hump
Being Caucasian or Asian descent
Slender, thin frame, small-boned
Early menopause
Sedentary lifestyle—lack of regular exercise
Low calcium in your diet
Alcohol or tobacco use
Eating disorders, including anorexia nervosa and bulimia
Long term use of certain drugs, such as steroids and anticonvulsants

Why is early detection of Osteoporosis so important?
There are now several medications that can effectively treat osteoporosis, and reduce the chance of a debilitating fracture. The likelihood of osteoporosis occurring in the future can even be predicted by noting the presence of a lower-than-average bone mineral density, a condition called “Osteopenia”. By beginning early treatment, osteoporosis can usually be prevented.

The DEXA bone densitometry examination
You will be asked to lie still on a comfortable table while low-dose X-rays are used to analyze the mineral content of both your spine and hip bones. The exam takes about 15 minutes and is completely painless. The amount of X-ray used is extremely small – equivalent to about 1/10 the dose received from a chest X-ray.

What is Vertebral Assessment?
Vertebral Assessment, called VA, is performed using state-of-the-art bone density equipment now available at River Radiology. VA allows the simultaneous diagnosis of existing vertebral fractures and bone mineral density in a single, brief exam session. The procedure exposes the patient to only about 1/100th of the radiation dose of a conventional x-ray. The analyzed report of the combined bone density and VA test results better help identify patients at risk for osteoporosis and more accurately determine their individual fracture risk.

When can my physician expect a copy of my report?
In most cases, reports are provided within two business days.

For more information about osteoporosis and bone densitometry, speak to your physician or contact the National Osteoporosis Foundation, 1150 17th St. N.W., suite 500, Washington D.C. 20036-4603 (phone: 202-223-2226; website: www.nof.org).