Bone Densitometry

What is a bone density test?

A bone density examination is used to measure bone mineral content and density. It may exist washed using X-rays, dual-energy X-ray absorptiometry (DEXA or DXA), or a special CT scan that uses computer software to determine bone density of the hip or spine. For various reasons, the DEXA scan is considered the "gold standard" or most authentic test.

This measurement tells the healthcare provider whether there is decreased os mass. This is a status in which bones are more brittle and prone to break or fracture easily.

A bone density test is used mainly to diagnose osteopenia and osteoporosis . It is also used to make up one's mind your future fracture risk. The testing procedure typically measures the os density of the bones of the spine, lower arm, and hip. Portable testing may use the radius (1 of the ii bones of the lower arm), wrist, fingers, or heel for testing, merely is not as precise equally the nonportable methods because merely one bone site is tested.

Standard X-rays may show weakened basic. Only at the point when os weakness tin be seen on standard X-rays, it may exist besides far advanced to treat. Bone densitometry testing tin can find decreasing bone density and strength at a much before stage when treatment can exist beneficial.

Illustration of T-score and what it means

Bone density test results

A bone density test determines the os mineral density (BMD). Your BMD is compared to 2 norms—good for you young adults (your T-score) and age-matched adults (your Z-score).

First, your BMD result is compared with the BMD results from good for you 25- to 35-year-old adults of your same sex and ethnicity. The standard difference (SD) is the difference between your BMD and that of the good for you young adults. This result is your T-score. Positive T-scores indicate the bone is stronger than normal; negative T-scores point the bone is weaker than normal.

According to the World Health Organization, osteoporosis is defined based on the post-obit bone density levels:

  • A T-score inside 1 SD (+1 or -i) of the young adult hateful indicates normal bone density.

  • A T-score of 1 to 2.5 SD beneath the immature adult mean (-ane to -2.5 SD) indicates depression bone mass.

  • A T-score of 2.five SD or more than below the young adult hateful (more than -2.v SD) indicates the presence of osteoporosis.

In general, the risk for os fracture doubles with every SD beneath normal. Thus, a person with a BMD of i SD below normal (T-score of -1) has twice the risk for os fracture as a person with a normal BMD. When this information is known, people with a high risk for bone fracture can be treated with the goal of preventing future fractures. Astringent (established) osteoporosis is defined equally having a bone density that is more than 2.5 SD below the young adult mean with one or more by fractures due to osteoporosis.

Secondly, your BMD is compared to an age-matched norm. This is called your Z-score. Z-scores are calculated in the same fashion, but the comparisons are fabricated to someone of your age, sexual activity, race, height, and weight.

In addition to bone densitometry testing, your healthcare provider may recommend other types of tests, such as blood tests, which may be used to find the presence of kidney disease, evaluate the function of the parathyroid gland, evaluate the effects of cortisone therapy, and/or assess the levels of minerals in the body related to bone strength, such as calcium.

Why might I need a bone density test?

A bone density exam is mainly done to look for osteoporosis (thin, weak basic) and osteopenia (decreased bone mass) so that these issues tin can be treated every bit soon as possible. Early handling helps to prevent bone fractures. The complications of broken bones related to osteoporosis are oft severe, particularly in the elderly. The earlier osteoporosis tin can be diagnosed, the sooner treatment can be started to improve the status and/or keep information technology from getting worse.

A bone density testing may be used to:

  • Ostend a diagnosis of osteoporosis if yous take already had a bone fracture

  • Predict your chances of fracturing a bone in the futurity

  • Determine your rate of bone loss

  • See if treatment is working

There are many risk factors for osteoporosis and indications for densitometry testing. Some common chance factors for osteoporosis include:

  • Post-menopausal women not taking estrogen

  • Advancing age, women over 65 and men over 70

  • Smoking

  • Family history of hip fracture

  • Using steroids long-term or certain other medicines

  • Certain diseases, including rheumatoid arthritis, type ane diabetes mellitus, liver disease, kidney disease, hyperthyroidism, or hyperparathyroidism

  • Excessive alcohol consumption

  • Low BMI (trunk mass alphabetize)