What is a peripheral Bone Density Scan (DEXA)?

Bone density scanning, also called dual-energy x-ray absorptiometry (DXA or DEXA) or bone densitometry, is an enhanced form of x-ray technology that is used to measure bone loss.  Peripheral DEXA devices, measure the wrist and forearm, are used for screening purposes.

 

The main purpose of obtaining a bone density test is determining fracture risk. The bone mineral density correlates very well with risk of fracture. The peripheral devices are good screening tools because of their portability, availability and lower cost, but patients may still need central testing (looking at the hip and lumbar spine), even in light of a normal peripheral test.  Your provider will review your results with you and determine if further testing would be indicated.

 

What are some common uses of the procedure?

Peripheral Dexa testing is recommended if you:

 

**The peripheral DEXA is not intended to be used in monitoring the effects of the treatment of osteoporosis and other diseases that result in bone loss.

 

Women should always inform their provider if there is any possibility that they are pregnant.

 

How does the procedure work?

The DEXA machine sends a thin, invisible beam of low-dose x-rays with two distinct energy peaks through the bones being examined. One peak is absorbed mainly by soft tissue and the other by bone. The soft tissue amount can be subtracted from the total and what remains is a patient's bone mineral density.

 

DEXA machines feature special software that compute and display the bone density measurements on a computer monitor.

 

The pDEXA bone density test is usually completed within 3-5 minutes

 

Your test results will be in the form of two scores:

T score — This number shows the amount of bone you have compared with a young adult of the same gender with peak bone mass. A score above -1 is considered normal. A score between -1 and -2.5 is classified as osteopenia, the first stage of bone loss. A score below -2.5 is defined as osteoporosis. The T score is used to estimate your risk of developing a fracture.

Z score — This number reflects the amount of bone you have compared with other people in your age group and of the same size and gender. If this score is unusually high or low, it may indicate a need for further medical tests.

Small changes may normally be observed between scans due to differences in positioning and usually are not significant.

 

What are the benefits vs. risks?

Benefits

Risks

 

What are the limitations of a peripheral DEXA Scan?

 

Exclusion criteria for the pDexa –

 

Insurance coverage:

Most insurance carriers cover a peripheral dexa scan.  You should always check with your insurance regarding what services are covered under your plan.  Some plans will only cover a percentage of the cost.  The remaining cost will be the responsibility of the patient.