Overview
Years ago, the only time osteoporosis — the disease that causes bones to become more fragile and likely to break — could be detected was after you broke a bone. By then, however, your bones might already be quite weak. Today a bone Densitometry test, also called densitometry, can determine if you have osteoporosis or are at risk of osteoporosis before you break any bones.
A bone Densitometry test uses special X-rays to measure how many grams of calcium and other bone minerals — collectively known as bone mineral content — are packed into a segment of bone. The higher your mineral content, the denser your bones are. And the denser your bones, the stronger they are and the less likely they are to break. Doctors use a bone Densitometry test to determine if you have, or are at risk of, osteoporosis.
Bone Densitometry tests are not the same as bone scans. Bone scans require an injection beforehand and are usually used to detect fractures, cancer, infections and other abnormalities in the bone.
Preparing For Your Bone Densitometry Test
The Bone Mass Densitometry Test is a very gentle experience and requires very little preparation.
You are encouraged to wear loose, comfortable clothes that are free of metal zippers, buttons or clasps. Alternately, you may wear one of our discreet cotton robes for the duration of the examination.
The test involves a small amount of radiation, about one tenth the amount used in regular x-ray. As with any medical procedure, if you are pregnant, you should alert your physician before you come in for your test.
What is a bone Densitometry test?
A bone Densitometry test uses special X-rays to measure how many grams of calcium and other bone minerals — collectively known as bone mineral content — are packed into a segment of bone. The higher your mineral content, the denser your bones are. And the denser your bones, the stronger they are and the less likely they are to break. Doctors use a bone Densitometry test to determine if you have, or are at risk of, osteoporosis.
Bone Densitometry tests are not the same as bone scans. Bone scans require an injection beforehand and are usually used to detect fractures, cancer, infections and other abnormalities in the bone.
What does the procedure consist of?
A bone Densitometry test (also called bone densitometry examination or scan) is an easy, comfortable procedure - you simply lie on your back on the cushioned platform of the densitometer and remain as still as possible. The arm of the bone densitometer moves over you, collecting the x-ray images as it goes.
Sessions last from 10-15 minutes, making it a quick, comfortable and simple test. When the images have been obtained, your session is over and you can resume your daily activities.
Who should have a bone Densitometry test?
Woman age 65 or older
Age 60 and at increased risk of osteoporosis
The older you get, the higher your risk of osteoporosis because your bones become weaker as you age. Your race also makes a difference.
You're at greatest risk of osteoporosis if you're white or of Southeast Asian descent. Black and Hispanic men and women have a lower but still significant risk.
Other risk factors for osteoporosis include low body weight, a personal history of fractures, a family history of osteoporosis and using certain medications that can cause bone loss.
How do you prepare for a bone Densitometry test?
Bone Densitometry tests are easy, fast and painless. Virtually no preparation is needed. In fact, some simple versions of the bone Densitometry tests can be done at your local pharmacy or drugstore.
Be sure to tell your doctor beforehand if you've had recent oral contrast or nuclear medicine tests. These tests require an injection of radioactive tracers that might interfere with your bone Densitometry test.
How is a bone Densitometry test done?
Bone Densitometry tests are usually done on bones that are most likely to break because of osteoporosis. These sites include the lumbar vertebrae, which are in the lower region of your spine, and the narrow neck of your femur bone adjoining the hip.
The equipment for bone Densitometry tests includes large machines on which you can lie down (central devices) as well as smaller, portable machines that measure bone Densitometry on the periphery of your skeleton, such as in your finger, wrist or heel (peripheral devices).
What can you expect after the test?
No recovery is needed after the test.
What are the results of a bone Densitometry test?
The results of your bone Densitometry test are reported in two numbers: T-scores and Z-scores.
T-score
Your T-score is your bone Densitometry compared with what is normally expected in a healthy young adult of your sex. Your T-score is the number of units - standard deviations (SD) - that your bone Densitometry is above or below the standard.
T-score What your score means
Above -1 Your bone Densitometry is considered normal.
Between -1 and -2.5 Your score is a sign of osteopenia, a condition in which bone Densitometry is below normal and may lead to osteoporosis.
Below -2.5 Your bone Densitometry indicates you have osteoporosis.
Keep in mind that these scores apply mostly to white postmenopausal women, who tend to have lower bone Densitometry as compared with other racial groups and men. Interpretations may vary if you're a woman of color or a man.
Z-score
Your Z-score is the number of standard deviations above or below what's normally expected for someone of your age, sex, weight, and ethnic or racial origin. This is helpful because it may suggest you have a secondary form of osteoporosis through which something other than aging is causing abnormal bone loss. A Z-score less than -1.5 might indicate these other factors are to blame. Your doctor would then try to determine if there's any underlying cause for the low bone mass. If he or she can identify a cause, that condition can often be treated and the bone loss slowed or stopped.
What are the pros and cons of the bone Densitometry test?
Bone Densitometry testing is a valuable tool in the diagnosis of osteoporosis and is a fairly accurate predictor of your risk of fractures. Significant differences in the various testing methods do exist, however. Central devices are more accurate, but cost significantly more than peripheral devices do.
A bone Densitometry test can confirm that you have low bone Densitometry, but it can't tell you why. To answer that question, you need a complete medical evaluation, including a history and physical. This information can help your doctor better interpret the results of the bone Densitometry test, as follows: