骨密度试验

定义

A bone mineral density (BMD) test measures how much calcium and other types of minerals are in an area of your bone.

This test helps your health care provider detect 骨质疏松症 or bone loss and predict your risk for bone fractures.

选择的名字

BMD test; Bone density test; Bone densitometry; DEXA scan; DXA; Dual-energy x-ray absorptiometry; p-DEXA; 骨质疏松症 - BMD; Dual x-ray absorptiometry

如何执行测试

Bone density testing can be done in several ways.

The most common and accurate way uses a dual-energy x-ray absorptiometry (DEXA) scan. DEXA使用低剂量 x射线. (You receive more radiation from a chest x-ray.)

DEXA扫描有两种类型:

• Central DEXA -- You lie on a soft table. The scanner passes over your lower spine and hip. In most cases, you do not need to undress. This scan is the best test to predict your risk for fractures, especially of the hip.
• Peripheral DEXA (p-DEXA) -- These smaller machines measure the bone density in your wrist, 手指, 腿, 或跟. These machines are found in some health care offices, 药店, 购物中心, 在健康博览会上.

如何准备考试

If you are or could be pregnant, tell your provider before this test is done.

DO NOT take calcium supplements for 24 hours before the test.

You'll be told to remove all metal items from your body, such as jewelry and buckles.

考试的感觉如何

扫描是无痛的. You need to remain still during the test.

为什么要进行测试

Bone mineral density (BMD) tests are used to:

• 诊断骨质流失和骨质疏松症
• See how well 骨质疏松症 medicine is working
• Predict your risk for future bone fractures

Bone density testing is recommended for all women age 65 and older.

There is not full agreement on whether men should undergo this type of testing. Some groups recommend testing of men at age 70, while others state that the evidence is not clear enough to say whether men will benefit from screening.

年轻的女人, 以及任何年龄的男人, may also need bone density testing if they have risk factors for 骨质疏松症. 这些风险因素包括:

• 50岁以后骨折
• 强烈的骨质疏松家族史
• History of treatment for prostate cancer or breast cancer
• 病史，如 类风湿性关节炎, diabetes, thyroid imbalances, or anorexia nervosa
• 早期 更年期 (either from natural causes or hysterectomy)
• Long-term use of medicines such as corticosteroids, thyroid hormone, or aromatase inhibitors
• Low body weight (less than 127 pounds or 57 kilograms) or low body mass index (less than 21 kilograms per square meter)
• 显著的高度损失
• Long-term tobacco or excessive alcohol use

正常的结果

The results of your test are usually reported as a T-score and Z-score:

• T-score compares your bone density with that of a healthy young woman.
• Z-score compares your bone density with that of other people of your age, sex, and race.

With either score, a negative number means you have thinner bones than the comparison group. The more negative the number, the higher your risk for a bone fracture.

A T-score is within the normal range if it is -1.0或以上.

异常结果意味着什么

骨密度试验ing does not diagnose fractures. Along with other risk factors you may have, it helps predict your risk for having a bone fracture in the future. Your provider will help you understand the results.

如果你的t分数是:

• 从1到2.5、你可能有骨质流失(osteopenia)
• 低于2.5、你可能有骨质疏松症

Treatment recommendations depend on your total fracture risk. This risk can be calculated using the FRAX score. Your provider can tell you more about this. You can also find information about FRAX online.

风险

Bone mineral density uses a slight amount of radiation. Most experts feel that the risk is very low compared with the benefits of finding 骨质疏松症 before you break a bone.

参考文献

刘建军，刘建军，刘建军. Dual x-ray absorptiometry and measurement of bone. In: Hochberg MC, Gravallese EM, Smolen JS, van der Heiide D, Weinblatt ME, Weisman MH, eds. 风湿病学. 8日艾德. Philadelphia, PA: Elsevier; 2023:chap 48.

Compston JE, McClung先生，Leslie WD. 骨质疏松症. 《十大赌博平台排行榜》. 2019;393(10169):364-376. PMID: 30696576 pubmed.ncbi.nlm.国家卫生研究院.gov / 30696576 /.

US Preventive Services Task Force; Curry SJ, Krist AH, Owens DK, et al. Screening for 骨质疏松症 to prevent fractures: US Preventive Services Task Force recommendation statement. 《十大赌博靠谱网络平台》. 2018;319(24):2521-2531. PMID: 29946735 pubmed.ncbi.nlm.国家卫生研究院.gov / 29946735 /.

韦伯TJ. 骨质疏松症. 参见:Goldman L, Schafer AI主编. Goldman-Cecil医学. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 230.