Bone Density Scans
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
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
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
- 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
- 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
An interview with Dr.
Ken Faulkner, chief scientist, GE Lunar Densitometers,
manufacturer of the DEXA device.
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
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.
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.
there guidelines on when women should begin to
have bone density tests?
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
you, Dr. Faulkner.