Bone mineral density, or BMD, is the main indicator of bone strength. Bone densitometry is an advanced technology in modern medicine and has just been introduced as a routine orthopedic test in China. It provides valuable and comparable data to determine the bone mineral content of the examined person by means of scanning, which is very important for judging and studying the physiology and pathology of bones and the degree of human aging, as well as diagnosing the effects of various diseases of the whole body on bone metabolism.
It is mainly used in 3 areas
Bone densitometry has a wide range of clinical applications, mainly in 3 areas.
1, early diagnosis of osteoporosis and prediction of fracture risk.
2, the measurement of bone mass in endocrine and metabolic bone diseases, so as to develop a safe and optimal treatment plan and prevent fractures.
3. follow-up and evaluation of the efficacy of the disease.
Simple method, no special preparation
Nowadays, most bone densitometers have the advantages of being highly accurate, easy to operate and non-invasive. Patients do not need special preparation before the examination, and the measurement is painless, similar to CT and X-ray examination. The measurement results are statistically processed by computer. In general, BMD is performed part by part, and the results reflect the BMD value of a particular part, while a comprehensive assessment of the whole body is required.
Application to 8 groups of people
The following groups of people can be considered for bone densitometry –
1.Females over 65 years old and males over 70 years old without other risk factors for osteoporosis.
2. Women under 65 years of age and men under 70 years of age with more than one risk factor (postmenopause, smoking, excessive alcohol or coffee consumption, lack of physical activity, calcium and vitamin D deficiency in the diet).
3.People with a history of fragility fracture or family history of fragility fracture.
4.People with low sex hormone level caused by various reasons.
5.X-ray shows osteoporotic changes.
6.Those who receive osteoporosis treatment and need to be monitored for efficacy.
7.Patients with diseases affecting bone mineral metabolism (renal insufficiency, diabetes, chronic liver disease, hyperparathyroidism, etc.) or taking drugs that may affect bone mineral metabolism (such as glucocorticoids, anti-epileptic drugs, heparin, etc.).
8. Pregnant women should have their bone density measured once in the 3rd and 6th months of pregnancy in order to supplement calcium in a timely manner.
Bone densitometer will automatically calculate the T value and Z value based on the patient’s data, and the T value is the most meaningful value for diagnosing osteoporosis, as it is the standard deviation (SD) number of young people who are above (+) or below (-) the BMD obtained from the test compared with the BMD of normal young people. Although the Z value is not very meaningful for the diagnosis of osteoporosis, it can reflect the severity of osteoporosis.
The World Health Organization (WHO) has determined the following four indicators based on the standard deviation (SD) between measurements of BMD levels and data from healthy young people.
Normal: BMD within 1SD of the mean value for young people (+1 to -1SD)
Low BMD: BMD was 1 to 2.5 SD below the average of young people (-1 to -2.5 SD)
Osteoporosis: BMD below 2.5SD of the mean for young people (below -2.5SD)
Severe osteoporosis: BMD below 2.5 SD of the average value for young people, accompanied by one or more osteoporotic fractures.
In general, each standard deviation decrease in BMD, regardless of the method of measurement and where it is measured, reveals an increased risk of future osteoporotic fractures of about 50%. However, BMD measured at a particular site is a better predictor of future fracture risk than when measured at other sites. Therefore, it is wise to test BMD at the site where bone pain occurs more frequently or to review BMD regularly at the site where bone loss has been measured.
If you have symptoms of suspected osteoporosis, go to the hospital for a bone density test and follow up regularly to determine whether bone loss is occurring and to detect and treat it early.