Transcript History of Bone Mineral Density Measurement

What is a
bone mineral
density test?
Who gets this
test done?
Why is it
needed?
How many
different
types?
HHHOLDORF
What do the
results mean?
What is a bone mineral density
test?
 A bone mineral density test or BMD measures how
much calcium and other types of minerals are in an area
of your bone.
 It is usually done to help your health care provider
detect osteoporosis and to predict the risk of bone
fractures.
Osteoporosis is characterized by progressive loss
of bone density, thinning of bone tissue and
increased vulnerability to fractures.
May result from disease, dietary or hormonal
deficiency or advanced age
Who gets this test done?
 You should have a BMD test or screening done if you are at
increased risk for osteoporosis
 You are more likely to get osteoporosis if you are
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A man over 70
A woman over 65
 Women under 65 and men the ages between 50-70 are at
increased risk of osteoporosis if:
 A broken bone, caused by normal activities, such as a fall from
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standing height or lower
Chronic rheumatoid arthritis, chronic kidney disease, eating
disorders
Early menopause
Smoking
Loss of height due to compression fractures in the back
Strong family history of osteoporosis
3 or more alcoholic beverages per day on most days
Taking corticosteroid medications everyday for more than 3 months
Why is it needed?
 Bone mineral density tests are used to:
 Diagnose bone loss and osteoporosis
 See how well you are responding to osteoporosis
medication
 Predict the risk of future bone fractures
How
many
different
types?
Bone density testing can be done several different ways.
 Most common and accurate way uses a dual-energy x-ray
absorptiometry (DEXA) scan.
 It uses lose-dose x-rays
 You receive more radiation
with a chest x-ray
 2 different types of DEXA scans:
 Central DEXA. You lay on a soft table while the scanner passes over
your lower spine and hip. Best to predict bone fractures.
 Peripheral DEXA. These are smaller machines which measure the
bone density in your wrist, fingers legs or heel.
What do the results mean?
 Normal results: Results are reported as a T-score and Z-
score
 T-score compares your bone density results to a healthy,
generally 30 year old of the same gender
 Z-score compares your bone density results to other people
your age, race and gender
 With either score, a negative number means your bones are
thinner. The more negative a number, the more apt the
bones are to fracture.
 A normal T-score range is between -1.0 and above.
What do the results mean? Cont’d
 Bone density tests DO NOT diagnose bone fractures. It helps
predict, along with other factors, the risk of a bone fracture
in the future.
 -1 to -2.5 signifies the beginning of bone loss (osteopenia)
 -2.5 or greater indicates osteoporosis
Hoffman, Matthew MD. “Living with Osteoporosis” WebMD. 3 June, 2013. http://www.webmd.com/osteoporosis/living-withosteoporosis-7/tests
Strock, Susan MD. “Bone Mineral Density Test” Medline Plus. 3 June, 2013.
http://www.nlm.nih.gov/medlineplus/ency/article/007197.htm
BMD measurement dates back as far as the 1940s’
It was measured using a plain radiograph (x-ray)
It was noted that bone lost was not apparent on an x-ray film until the
patient lost approximately 40% bone mass, making it too late to treat
 In 1960, a young medical physics professor from the
University of Wisconsin invented bone densitometry.
Bone densitometry is the measurement of bone
mineral content utilizing a precise amount of radiation.
 Since the radiation doses were in small amount, often
his graduate students would volunteer to be research
subjects.
 He discovered that lactating mothers had a small
change in their bone mineral, thus making it
impetrative for young mothers to supplement during
lactating years.
One of Johns’ early bone densitometry
publications (Invest. Radio. 3:141; 1968) was
listed as its single most cited article on the 25th
anniversary of Investigative Radiology.
As we get older we all
loss some bone mass
Our bones become
thinner, and this is
called osteopenia
Therefore making
them (bones) less
dense and porous
It makes the bones
lighter and weaker,
and a chance of
breaking
This can happen to
men, but is more
prevalent in women
who are65 or older .
The bone density
scan was invented
to help measure
When this occurs, our
bones lose calcium and
other important
minerals (due to
hormonal decline)
Osteopenia leads
to osteoporosis
The amount of
matter in bone,
sucked out as
calcium.
John was deeply concerned with excess radiation exposures in diagnostic
radiology. He developed simple test tools and techniques to measure radiation
and to evaluate the quality of x-ray images. These efforts led to the creation of
Radiation Measurements, Inc. (RMI), a pioneering manufacturer in qualityassurance measurements, materials, and devices. This also led to product
developments by several companies and to several standard techniques for
radiation measurement and image quality assurance.
The Lunar Radiation was developed by GE in the late 90s’ and was an extension
of what John Cameron developed some 30 years prior
John died on 16 March 2005 at age 82 in Gainesville,
Florida, where he lived during the winter months and
served as a Visiting Professor in the Department of
Radiation Oncology at the University of Florida.
Case Study
Patient History
• A 60-year-old Caucasian female is in for an annual
checkup. The patient experienced menopause in her
early 50’s and has been in good health. Other than
hormone therapy (HT) the patient is on no other
medications.
• The patient has no history of fractures, stands at 5’7”.
112 lbs. and rarely exercises. Smokes cigarettes and
is a regular coffee drinker.
• Although no personal injuries, her sister has past
experience of a hip fracture.
Risk Factors
• Although the patient has no history of fractures,
she does have characteristics that put her at
higher risk of fractures significantly seen in
Caucasian women.
• Risk factors which may increase fractures:
• Increased fractures as an adult
• Family history of fractures
• Low body weight (Less that 130 lbs.)
• Smoking
Patient Evaluation
• After annual checkup, no abnormalities were
found.
• No signs of loss of height were noted
• Patient’s vitamin D and calcium
levels remained consistent with
past examinations
• Although there were no abnormalities during
checkup, BMD testing was recommended due to
normal risk factors with age.
BMD Test Results
• BMD tests reveled a left hip T-score of -1.5, which
is considered a fairly low score and prompted
consideration of what could be causing a low
score and bone-loss.
• All other test results were said to be
normal, including normal serum thyrotropin,
serum 35-hydroxyviatmin D, and cortisol
levels.
• With a low T-score for the hip, the patient is
considered to have low BMD, also known as
osteopenia, which increases the patient’s risk
for future fractures.
Recommended Preventative Strategies and
Treatment for Osteopenia
• Patient is highly encouraged to quit
smoking – women smokers are typically
thinner and undergo menopause at an
early age, there is a higher risk facture for
fractures
• Calcium supplements are recommended to
ensure intake of daily calcium requirements
– about 500 mg at a time
• Weight-bearing exercise is highly
recommended to build muscle mass and
tone for protection. Although swimming is
not weight-bearing, many patients chose
swimming to improve strength without
high impact risk.
• Fall prevention- Studies have proved that over 90% of hip and wrist
fractures are results of a fall, so taking measures to reduce the risk
of falls in your home and work are recommended – especially for
elderly
Hormone Therapy
• Controlled studies have demonstrated that hormone
therapy has decreased vertebral fractures by at least
one/third
• Hormone therapy has decreased overall fractures by 2430%
• Although hormone therapy is
effective, it is not recommended as
the sole treatment or used for disease
prevention – there can be risk factors
such as stroke, cognitive impairment,
and deep vein thrombosis
• Increased risk of breast cancer
can also be seen in HT
Patient Summary
• With risk factors included in HT, the patient
discontinued use.
• Discontinue raises the patient’s risk up to 4% in
the first year for increased BMD
• Patient is recommended calcium and vitamin D
supplements, and adequate daily exercise to
increase body mass.