The full form of DXA is “dual-energy X-ray absorptiometry.” A DXA scan is a type of medical imaging test. It uses very low levels of x-rays. It is considered the gold standard to measure the body composition-bone, fat and muscle health.
DXA or the bone densitometry tests measure the mineral content of the bones in certain areas of the skeleton. It’s a way to measure bone loss with ageing and diagnosisosteoporosis. It is considered the gold standard to measure the body composition-bone, fat and muscle health.
According to the World Health Organisation, DXA scan is the gold standard to diagnose osteoporosis.
– Track bone health changes over time
– Monitor your response to treatment, such as an osteoporosis medication
– Evaluate body composition, such as how much fat and muscle mass your body has (and where)
Understanding body composition is important for prediction of health and disease. It helps in understanding and planning the lifestyle management techniques for good health. It helps plan performance, improves quality of life and increases longevity. A well toned body with good posture enhances appearance
– No calcium supplements for at least 24 hours before test.
– Avoid cloths with metals e.g. zippers, buttons
– Wait for 10-14 days if you had a barium enema examination or have been injected a contrast material for CT or radioisotope
– Should not be done if you are pregnant
There are two types of reports
1. Bone density reports: Bone is most easily seen in white, while the fat and muscle tissue look like shadows in the background on the technologist’s computer monitor
2. Body composition report: Gives the percentages and the content of bone seen in white, fat as yellow and and muscle as brown and BMI. It gives the amount of visceral fat, segmental analysis of muscle mass and bone and also gives the resting metabolic rate
You will be asked to lie on a special DXA x-ray table. The technologist will help position your correctly and use positioning devices such as foam blocks to help hold the desired position. The scanner translates the bone density measurement data into pictures and graphs.
DXA is quick and painless. But you’ll only need to stay in a position for a few minutes. It takes about 10–30 minutes, depending on the areas being scanned.
Indications for DXA- Indian Guidelines
• All postmenopausal women more than 5 years of menopause.Postmenopausal women less than 5 years of menopause with risk factors
• Women in menopause transition with secondary causes. Radiological evidence of osteopenia and the presence of vertebral compression fracture
• Women with fragility fractures by radiology or DXA
• Ideally, before initiating pharmacotherapy for osteoporosis
• Emerging indications are to measure total body and regional fat, lean tissue mass.
DXA scans offer a high degree of precision and accuracy. Unlike x-ray machines, DXA machines are checked daily for their ability to measure bone mineral accurately, and no two DXA machines are exactly alike. That is why your healthcare provider will insist that you have all of your DXA tests done on the same machine. These results are then reviewed and interpreted by a physician trained in DXA interpretation