DEXA stands for dual-energy X-ray absorptiometry, meaning two X-ray beams are aimed at the bones during the scan.
It is also called a central DEXA scan,bone densitometry scan, or DXA scan.
This article explains a DEXA scan, who might need one, the procedure, and the results.
Illustration by Cindy Chung
What Is a DEXA Bone Scan?
A DEXA scan can diagnose if someone has osteoporosis or bone thinning.
It usesX-raysand determines a bone mineral density (BMD) score.
BMD allows you and your healthcare provider to understand how strong your bones are.
BMD from a DEXA scan can help identify osteopenia, osteoporosis, and fracture risk.
Nearly one-fifth of females over the age of 50 will develop osteoporosis in their lifetime.
Osteoporosis can affect men, too, although it is less frequent.
These other tests that look at BMD include:
A DEXA scan is solely used to assess BMD.
An MRI can identify causes of bone pain (e.g., in cases of back pain) or cancer.
A qCT scan is a CT scan specifically used to measure BMD.
A DEXA scan uses X-rays, which are less radiation than a CT scan.
This is one reason why a DEXA scan is generally preferred over a CT scan for BMD.
Who Should Have a DEXA Scan?
Females are at ahigher risk of osteoporosisthan men.
This is because men are at a lower risk of osteoporosis than females.
Medication effectiveness may differ between males and females due to differences in hormones, such as estrogen andtestosterone.
Limitations and Contraindications DEXA Scans
Certain conditions can make DEXA scans less accurate.
Instances where DEXA scans may not be as accurate include:
Different machines have various weight limitations.
If you are pregnant, discuss the risks and benefits of the exam with your healthcare provider.
They may recommend delaying the scan until after pregnancy or until you are farther along.
Is a DEXA Scan Safe?
The main safety concern with DEXA scans is radiation.
These scans utilize very little radiation.
Since the test utilizes X-rays, any metal can interfere with the results.
You will also be asked to remove any jewelry.
T score: The T score compares your bones with bones that are considered healthy.
So, a T score is comparing your bone density with that of young, healthy adult bones.
Z score: The Z score compares your bones with those of others who are of similar age.
The T-score is what is commonly looked at because it shows age-degenerative changes.
T scores fall into the following categories:
Several treatment options exist.
However, certain conditions must be met in order for insurance to cover the test.
Contact your carrier prior to your scan to understand if you are responsible for any out-of-pocket costs.
They can also be used to monitor the effectiveness of treatment for these conditions.
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