What is a DEXA scan?

St. Joseph’s/Candler Certified Clinical Densitometrist answers seven questions about bone mineral density testing

You may not think of osteoporosis as a serious condition compared to heart disease or cancer. However, the numbers may be eye opening.

A woman’s lifetime risk of hip fracture alone is equal to the combined risk of developing breast, uterine and ovarian cancer. And, up to 20 percent of women who suffer hip fractures die within one year of the fracture than those of similar age who haven’t suffered a hip fracture.

Early detection using bone density measurement is the best way to protect you from the potentially debilitating effects of osteoporosis.

Osteoporosis is a disease that gradually weakens bones, causing them to become brittle and prone to fractures. Osteoporosis and its associated fractures can rob you of your mobility and your independence.

“We know that fractures, especially hip fractures, tend to send people into other co-morbidities,” says RaDonna Pirkle, Physician’s Assistant and Certified Clinical Densitometrist at St. Joseph’s/Candler. “They tend to develop a sedentary lifestyle, gain weight and get depressed.”

It’s not just women who should be concerned about osteoporosis. About 54 million Americans have osteoporosis and low bone mass, according to the National Osteoporosis Foundation. Studies suggest approximately one in two women and one in four men age 50 and older will break a bone due to osteoporosis at some point in their remaining lifetime.

There are numerous contributing factors that can cause osteoporosis. Some of these are:

• Family history of osteoporosis
• Smoking
• Heavy alcohol use
• Getting little or no exercise
• A diet low in foods containing calcium, phosphorus and Vitamin D
• Certain medical conditions such as hypothyroidism or rheumatoid arthritis
• Certain medications
• Soft drink intake

Related Article: Another reason to avoid soda: help prevent osteoporosis

To learn if you have osteoporosis or osteopenia (when your bone density is lower than normal but not low enough to be osteoporotic), a machine can measure your bone density. The machine used at St. Joseph’s/Candler imaging centers is called dual-energy X-ray absorptiometry, or DEXA.

“Osteoporosis is more common than lung cancer and breast cancer put together, but it’s not one of the big C’s so it gets put to the side,” Pirkle says. “Chances are if you end up with osteopenia or osteoporosis you are going to get hurt and became fragile, and once you are fragile, it’s hard to come back from that.”

Medicaid’s recommendation for a bone mineral density test is every two years in post-menopausal women. Men over the age of 50 to 55 also should begin testing.

Here are seven things you should know about a DEXA scan.

1. What is a bone density measurement?
Bone density measurement will determine your bone mineral deposit (BMD) for the areas measured and compare that result with the average BMD of the same age, race and sex, as well as someone with peak bone mineral density, which is typically a 30-year-old of the same race and sex. The areas of the body measured during a DEXA scan are the non-dominant hip (cancellous bone) and lower lumbar spine (cortical bone). If there’s been a hip replacement, the dominant hip will be measured, and if both hips have been replaced, the forearm can be used, Pirkle says.

2. Who is it for?
Most DEXA scans are done on post-menopausal women, Pirkle says. However, she has read results for younger women, men and even young children. Certain drugs, such as steroids or anti-seizure medications, and autoimmune disorders, such as Crohn’s disease, can lead to bone density loss regardless of age. Chemotherapy and radiation also can cause low bone density.

If you are concerned about your bone density or you have a family history of osteoporosis, talk to your doctor. Some insurance companies may cover a bone density mineral test depending on your medical and family history.

3. How long does it take?
A DEXA scan is a simple, safe, non-invasive and painless X-ray. It can be as short as a couple of minutes up to 20 minutes. Patients should plan to arrive early to their appointment as they will have to fill out a questionnaire about their medical and medication history. This questionnaire can help explain test results and may determine if a bone density test is needed every year versus every two years, Pirkle says.

4. What should I wear?
Wear comfortable clothing, preferably something without metal buttons, buckles or zippers. Body jewelry, such as belly button rings, need to be removed. Facial and wrist jewelry should be fine, Pirkle says.

5. How much radiation will I be exposed to?
You will be exposed to very little radiation. In fact, in most cases, less than a standard chest X-ray.

“Being in the sun for 10 minutes exposes you to more radiation than the exposure from a DEXA Scan,” Pirkle says. “It’s the lowest energy they make.”

As with any procedure, be sure to tell your doctor and the technician if you are pregnant.

6. What do the results mean?
Test results from a bone density test produce a T-score and a Z-score. The T-score compares your BMD to the peak of a 30-year-old healthy adult of your sex. The Z-score compares your BMD to someone of your age, weight, height, sex and ethnic or racial origin.

T-score results are:

• Above -1.0: Bone mass is about normal
• -1.0: Bone mass is about 10% below normal
• -1.5: Bone mass is about 15% below normal
• -2.0: Bone mass is about 30% below normal
• -2.5 or less: You are osteoporotic

If your Z-score is -2 or lower it may mean something other than aging is causing abnormal bone loss. Pirkle typically reads results the same day as the scan. Patients will learn their results from their referring physician.

7. Where can I get this scan?
Bone density screening is available at the Telfair Pavilion at Candler Hospital, SJ/C Imaging Center – Pooler, SJ/C Imaging Center – Bluffton and Telfair Breast Imaging Center – Eisenhower. A physician’s referral is required for testing. For more information or to schedule your appointment, call:

• 912-819-7000 (Telfair Pavilion)
• 912-748-0068 (Pooler)
• 843-836-4300 (Bluffton)
• 912-691-1460 (Eisenhower)

Treatment

If a DEXA scan determines you have osteoporosis, there isn’t need to despair. Proper treatment, such as increasing vitamin intake and exercise, can help protect and strength your bones.

“I have seen a lot of cases where patients have increased their bone density just by taking over-the-counter calcium, Vitamin D and a multivitamin,” Pirkle says. “Just be sure to talk to your doctor.”

Continue to read Living Smart every week for more health topics, including a follow-up to this post that goes more into osteoporosis treatment.