Bone Density Scans

Date

The Test Women Don’t Think About

Editor’s Note: Osteoporosis is one of the most insidious degenerative diseases plaguing Westernized countries. Radiologist Edward Strauss, M.D., with comments by Ken Faulkner, Ph.D. and Susan Brown, Ph.D., director of The Osteoporosis Education Project, tell about an advanced form of bone screening called DEXA.

Most women know they need to be screened for breast cancer but how many think about being tested for something that is much more likely to affect them, osteoporosis? Women have a lifetime risk of 40 percent of getting osteoporosis. That’s equal to the combined risk of breast cancer, uterine cancer and ovarian cancer. Yet they don’t routinely get themselves screened for the early signs of this disease.

The need for regular mammograms is something most women understand and that’s good, but they don’t think about bone density scans. Regular screenings for osteoporosis can allow a woman to protect herself from a disease that could cripple and even kill her. It would be tragic to have something so easily treatable go undetected.

Women have been conditioned to think that osteoporosis is an inevitable part of aging. You get old, you get shorter. That’s just the way it is, many women reason. Not so. There are steps that can be taken to prevent the disease. Or if that’s not possible, there are new treatments to halt bone loss and even rebuild bone mass. With early detection and intervention, many women can avoid this crippling and life-threatening disease.

Osteoporosis is a silent, progressive disease characterized by decreased bone density and increased bone fragility. It affects 15 to 20 million people in the U.S. at any given time and is responsible for $13 billion in healthcare costs. Fractures of the hip and spine have the most dramatic effect on people’s lives.

One-quarter of the deaths experienced by elderly people are a direct or indirect result of hip fractures. Half of the older adults who survive hip fractures will not be able to walk without assistance and 25 percent of these survivors will require nursing home care. Spinal fractures result in constant pain, deformity and loss of height, a stooped posture and disability.

What many women don’t know is that osteoporosis is treatable and the earlier it’s caught, the better. New advances in bone density scanning have allowed us to identify women who are at risk decades before any signs of the disease appear. A bone density scan isn’t one of those tests that just alerts you to the presence of the disease so you can worry about it. It gives you the information to do something about it before it has any effect on your life. But first you have to detect it.

At Norwalk Radiology and Digital Mammography Center we prefer to use an advanced form of bone density screening called DEXA to detect precursors to the disease. We find that DEXA is the most accurate and reproducible of the bone density measurement tests. This means we can pinpoint the need for treatment and gauge the response to that treatment precisely. We also like the fact that it produces these results with extremely low doses of radiation—less than 1/100th of a chest x-ray.

DEXA stands for Duel Energy X-ray Absorptiometry. It uses an x-ray beam of two different energies that enables doctors to measure bone strength without being confused by other tissue, like muscle, fat and skin. This is especially important because it allows doctors to measure bone density in the two most important areas: hips and spine. These areas used to be almost impossible to measure because they are deep in the body surrounded by tissue. But it is critical to find out about bone density in these two areas because that’s where the most disabling fractures occur.

DEXA also allows doctors to compare a woman’s results to those of women similar to them. This technology lets us see how a woman compares to others of the same age, race, weight and height and gives us the ability to extrapolate her results into the future. For example, suppose we scan a 35-year-old premenopausal woman. Her bones are not so bad, maybe a bit below average if you measure her against the general population. But relative to other 35-year-olds who are at her height, weight and race, she’s lower than she should be.

She doesn’t have a problem now but she could be headed for real trouble in 20 years. We’ll want to look at things like her family history and lifestyle. We will also look into the medications she’s taking that lower bone density and see about any hormonal imbalances. After that we can decide whether there should be changes in her lifestyle, diet, exercise or her use of supplements. We may even look into the possibility of medication to build bone mass today in advance of menopause. Women in menopause suffer an accelerated loss of bone mass.

• The following groups should be concerned about a bone density screening:
• All women within a few years of menopause, particularly if it could have an impact on their decision to take hormones or not.
• People with risk factors such as a positive family history. If you’ve got a mother or grandmother who had problems with fractures or what is called a dowager’s hump, you are at particular risk for osteoporosis.
• Women who had early menopause (in their 30s) due to the removal of ovaries or other reasons.
• People on medications. Certain medications such as steroids, blood thinners or treatments for thyroid problems may decrease bone mass.
• People with a known history of fractures or bone injuries that are not caused by massive trauma. If you are someone who gets stress fractures from something as simple as jogging, that could be a warning sign.
• Postmenopausal women.

The bottom line is that osteoporosis is not inevitable. It is detectable and treatable. Often what needs to be done are things that should be part of any healthy lifestyle like eating a varied diet, taking in enough calcium and participating in a regular exercise program.

All women need to be aware of their risk of osteoporosis and protecting themselves against it. It’s an important part of taking control of your own health.

Dr. Edward Strauss is a board-certified radiologist who specializes in analytical studies. An expert in the field, he has served as an examiner for the American Board of Radiology and has been named for several consecutive years as one of the country’s “Top Doctors.” Norwalk Radiology is a full-service diagnostic imaging center staffed by fellowship trained radiologists. For more information on detecting and treating osteoporosis visit www.norwalkradiology.com

BONUS CONTENT

An interview with Dr. Ken Faulkner, chief scientist, GE Lunar Densitometers, manufacturer of the DEXA device.

TH:Dr. Faulkner, please give us a brief overview of the DEXA devices and how they compare to other forms of x-ray exposure.

KF: DEXA devices were introduced in 1987. This was the first time we had x-ray beam devices to measure bone density at the spine and hip. However, due to the fact that there were not many effective treatments for osteoporosis, the devices weren’t used much at the time. The field began to change in 1995 when effective treatments for strengthening bones and treating osteoporosis began to enter the market. DEXA measurements use a fraction of a dose of conventional x-rays. X-rays are used but it is not the image, it is the bone density measurement. Because we don’t have to get nice images, the amount of x-rays we use is extremely small—about a tenth or even a hundredth of a mammogram or chest x-ray. This is equivalent to a transcontinental airplane flight—even actually less than that. Very, very low decimal radiation.

TH: How many bone densitometers are currently in use?

KF: I think in the U.S. there are about 6,000. Globally there are about 12,000.

TH: Do you have any idea how many individuals are benefiting from this technology every year?

KF: Many are not benefiting, I am sorry to say. Recently a paper in the Journal of the American Medical Association (JAMA) indicated half the women over the age of 50 potentially have low bone density but are not being measured. There is also data from the drug companies indicating that 77 percent of women who have osteoporosis are currently not being evaluated or treated. This is not surprising since it is a relatively young technology—it takes a while to catch on.

TH: Are there guidelines on when women should begin to have bone density tests?

KF: According to the National Osteoporosis Foundation, they recommend that all women over 65 have a bone density test. Also, all postmenopausal women, even if they are under 65, should have the test if they have one risk factor for osteoporosis besides menopause. Things like if they have had a facture, if relatives have had a fracture, or risk factors like smoking, drinking or low calcium intake and low exercise, those are big risk factors for osteoporosis so it is recommended that they are screened as well.

TH: Thank you, Dr. Faulkner.