Dual Energy X-Ray Absorptiometry (DEXA or DXA)

What is Dual Energy X-Ray Absorptiometry? It is a simple radiology scan designed to measure the density of the bone. Measurements are taken at the spine, hip and wrist.

Why measure the thickness of the bone? The density of the bone can be used to predict the risk of bone fractures. By using this test, we can identify those who will benefit from more therapy.

Does the test hurt? Absolutely not. The test takes around ten minutes and you don't even know they are doing the scan.

Is the test safe? Yes! The total amount of radiation is 1/10 the dose of a standard chest x-ray.

I have gotten the results of my DEXA Scan and I don't understand them. Can you explain what the results mean? The results are given in numerical form and require physician interpretation. In lay terms, the results are given as two different scores-the T-Score and Z-Score.

The T-Score compares your bone density to that of a person who is thirty years old. This age was chosen since it is the time when you attain your peak bone mass. Comparison to this number allows the physician to see how much bone loss has occurred. The scores are reported as standard deviations (SD) above or below peak bone mass. One standard deviation below is approximately equal to a 10-15% decrease in bone density. The scores are given in positive and negative numbers where a negative number represents bone loss.

Bone goes through various stages of thinning: normal-osteopenia-osteoporosis.

The World Health Organization classifies T-score values above -1 as normal. A score between -1 and -2.5 is considered osteopenia. Any score below -2.5 is defined as osteoporosis.

With each increase in the negative T- Score of one, the risk of fracture increases 1.5 to 3 fold! So, even if you are diagnosed with osteopenia, you are still at an increased risk of injury.

The Z-Score compares your bone density to that of a person your own age. It is the number of standard deviations above or below the mean for your age. It is not used in making medical decisions but gives you an idea of how you stack up to your peers.

I still don't understand osteopenia? Remember that bone is not like concrete. It's a dynamic living tissue. Normal bone goes through a continual growth and destruction. If the breakdown of bone is greater than the rebuilding, bone is lost. Osteopenia is the first stage of bone loss. When the T-Score is between -1 and -2.5, it is classified as osteopenia.

Is there anything I should do if my T-Score is normal? Yes. Speak with your physician regarding your specific risk factors. Remember, osteoporosis is a progressive and silent disease. Normal bone density today shouldn't make you complacent. Calcium supplementation and exercise are an absolute minimum. Preventative therapies should be discussed with your physician.

What should I do if I have osteopenia? A discussion with your physician is imperative and treatment should be considered. Exercise and calcium should be an important part of any program.

What should I do if have osteoporosis? Consultation with a physician is very important. Although most cases of osteoporosis in women are related to menopause, there may be an underlying medical condition. A complete check-up is necessary before starting treatment. Calcium supplementation in conjunction with a specific osteoporosis exercise program should be part of any treatment program.