As you age, your bones start becoming fragile and weak. There can be other reasons for weakening of bones such as prolonged illness, addiction and genetic conditions. Bone densitometry is a test suggested to determine the peripheral bone mineral density (BMD). A snapshot of the bone is taken that helps identify your risk to fractures, osteoporosis and your chances of recovery.
Central dual-energy x-ray absorptiometry or central DXA test is the most recommended and recognized BMD test. It is painless, almost similar to having an X-ray and measures the bone density at your spine and hip. The test is carried out for the screening purposes. The BMD test measures the mineral density of the bone, compares it to the standard or the established norms for bone density, and present to you a score.
What is a T-score?
Even though, 100 percent bone density or accuracy is impossible, the test predicts whether your bones are more vulnerable to breakage and fractures. The score is compared to the bone density score of a healthy 30-year-old individual and accordingly you get a T-score. For example, if you are given a score of 0, it means that your BMD score is equivalent to the score of a normal healthy individual.
Standard deviations (SDs) are a unit used to measure the difference between your BMD and the score of a healthy young adult. If your SDs is below zero it means your score is negative. Higher the BMD, lower your risk of getting fracture and vice-versa.
Significance of Bone Densitometry
A bone densitometry test helps the doctors to identify whether you have normal, low (osteopenia) density or osteoporosis. At present, it is the only test that can identify osteoporosis. The test helps your caregiver identify:
- Whether your bones are weak, vulnerable to breakage
- Whether you are suffering from osteoporosis
- Whether the medications are improving your bone density, staying the same or getting worse
Who Should Undergo BMD Test?
You must undergo a BMD test if:
- You are a woman aged 65 years or more
- You are a man aged 70 years or more
- You are a woman in menopausal age with several health risks
- You have a history of bone breakage in the fifties
- You are postmenopausal women below 65 years of age
- You are a man in between 50 to 90 years with health risks
You may also be advised a bone densitometry test if you suffer from either of the following:
- Loss of height of half inch or more in the last one year
- Your spine X-ray shows bone loss or bone breakage in the spine
- Pain in the back with a possibility of breakage in the spine
- Total loss of height of around one and a half inches from the original height
Should you repeat a BMD Test?
People who are undergoing osteoporosis treatment should repeat the BMD test every one to two years.
What are the Benefits of Bone Densitometry Test?
The benefits of BMD test include:
- It is noninvasive, quick and simple
- It does not require anesthesia
- The use of radiation is in very small amount, almost 1/10 of that used for a standard chest X-ray and much lesser than the exposure you get through natural radiation.
- It is one of the most accurate methods currently available for diagnosing osteoporosis.
- It is also considered to be the most accurate estimator of fracture risk
- The equipment is widely available making the test convenient for the doctors and the patients alike
- The chances of radiation entry into the body of the patient after the test is almost none
- It usually does not cause any side effects, as is the case after most of the diagnostic examinations.
What are the Risks of BMD Test?
Excessive exposure to the radiation can increase your chances of cancer, though the benefits outweigh this slight risk.
Women should inform the radiologist or the physician if they are pregnant prior to the test as the radiation can stunt the growth of the fetus.