Osteodensitometry (DEXA)

Osteodensitometry (DEXA) is a diagnostic scan that determines bone mineral density. The mineral content of bones in certain parts of the skeletal system is precisely measured. With the help of this test, doctors can determine and monitor the loss of bone density that occurs in aging or hormonal disorders. Modern DEXA devices also measure body composition – the ratio of muscle mass and fat tissue in the body, which is very important for determining the risk of certain diseases, as well as monitoring the results of training in athletes or the results of a diet the patient is adhering to.

A DEXA scan is a type of radiology exam that uses very low levels of X-rays to measure how dense a patient’s bones are. DEXA stands for “dual-energy X-ray absorptiometry”. The medical world considers the DEXA scan to be the most useful and practical test for diagnosing osteoporosis.

Osteoporosis is a term used to describe brittle bones that, most often with aging, lose mass and strength. This disease occurs when the bones weaken faster than the body can create new bone tissue.

Osteopenia is the loss of bone density to a lesser degree than in osteoporosis. Reduced bone density means your bones do not have as much mineral content as they should. This can make them weaker and increase the risk of fracture. If you have osteopenia, your bone density is lower than average and can further progress to osteoporosis.

It is recommended that all patients above the age of 50 years and women entering menopause (due to hormonal changes) monitor and check their bone density every few years.

What are the indications for osteodensitometry?

Women aged 65 years or older are at high risk of losing bone density, which can easily lead to fractures. You may also be at risk of low bone density if:

• you have a very low body weight.
• you have had one or more fractures after the age of 50.
• you have lost 1.5 cm or more in height over a period of one year.
• you are a man older than 70 years.
• you have a family history of osteoporosis.

Other risk factors include the following:

• Lack of physical activity
• Smoking
• Excessive alcoholintake
• Insufficient amounts of calcium and vitamin D in the diet
• Long-term use of corticosteroids

Preparing for a DEXA scan

Before the imaging procedure, it is important to follow the simple instructions provided by your doctor. Guidelines may refer to discontinuing calcium supplements 24 to 48 hours before the test. You should also avoid wearing metal jewelry or clothing with metal parts, such as buttons or clasps, during the scan.

We advise that you wear comfortable clothing which can easily be removed at the request of the doctor if they assess that the clothing will interfere with a particular area of the scan.

Inform your doctor if you are pregnant or suspect pregnancy, so that theycan consider alternative tests and assess whether DEXA is necessary and appropriate for you.

How is DEXA scanning performed?

Before starting the scan itself, the radiology technician will measure your height. You will then be asked to lie down on an examination table where it is important to be completely still while the DEXA scanner moves over a specific area of the patient’s body – usually the lower spine and hips.

The recording itself usually takes up to 15 minutes. As the scanning machine moves over your lower spine and hips, at the same time another scanning machine called a photon generator passes underneath you. The images from the two machines are then combined and sent to the computer.

To measure bone density in the forearm, finger, hand, or foot, a doctor may use a portable scanner known as a peripheral DEXA (p-DEXA) scan.

A bone density scan is used for the following:

• Diagnosing osteopenia (low bone mass)
• Diagnosing osteoporosis
• Predicting the risk of future fractures
• Checking if osteoporosis treatment is working

What can you expect after a DEXA scan?

After the scanning is complete, the images and scan report are analyzed by a radiologist and the results are then sent to the doctor who referred you for this scan or they are issued to you personally.

Your DEXA scan results are obtained using the so-called “T-score”. This means that the scan results are compared with the maximum bone mass – the normal bone density in healthy people between the ages of 23 and 35 years. A term also known in this field is the “Z-score“, which is obtained by comparing your results with the bone density of people your age.

If your results show that you have low bone density, your doctor will recommend steps to prevent further bone loss. This may include the following:

• More exercise, with activities such as walking or dancing
• Adding calcium and vitamin D to your diet
• Taking the prescribed therapy/medications to increase bone density

If you have questions about your results and/or bone loss treatments, talk to the medical team of the MD Clinic.