WHAT IS A DEXA SCAN

DEXA stands for Dual-energy X-ray absorptiometry. It is a scan used to assess bone density and therefore strength. 

A DEXA scan can be helpful in diagnosis and assessing osteoporosis and estimating fracture risk. 

WHAT IS THE PROCEDURE OF A DEXA SCAN?

When you have the scan you lay still on your back on a X-ray table while the arm of the machine passes over you. Low dose X-ray beams pass through your body and leave an image behind. This procedure is performed by a radiologist. It is a painless procedure and usually takes about 25-30 minutes.

UNDERSTANDING THE RESULTS OF A DEXA SCAN

The results of the scan compares your bone density with the expected bone density of a healthy adult and of a healthy adult of the same age, gender and ethnicity. 

The difference between you and the expected value is calculated as a standard deviation. When comparing to a young healthy person a T score is calculated and when comparing to someone of the same age, gender and ethnicity it’s called a Z score. 

A Z score is generally used for children and people still growing. 

T score is more commonly used in older adults.

If you are -1 standard deviation less than the young health adult this is normal. 

If your T score is between -1 and -2.5 then you have a reduced bone density and may be classified as osteopenic. 

Below -2.5 standard deviations is defined as osteoporosis. 

Keynotes for osteoporosis blogs : 

https://www.aihw.gov.au/reports/chronic-musculoskeletal-conditions/osteoporosis/contents/what-is-osteoporosis 

https://www.mayoclinic.org/diseases-conditions/osteoporosis/symptoms-causes/syc-20351968

https://www.mayoclinic.org/tests-procedures/bone-density-test/about/pac-20385273 

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Dr Mariella Berry (Osteopath)

BSC (Osteopathy), MHSc (Osteopathy)