Posts Tagged ‘bone density test’

Bone Density Testing: What is it and Why is it Important?

bone density testing at Peninsula Radiology

What is bone density testing?

Bone density testing—also known as dual-energy x-ray absorptiometry (DEXA or DXA)—uses x-ray images to assess bone mineral density (BMD). The absorption of dual x-ray beams by a patient’s bone is measured to determine the overall strength of the bone and the risk of fracture. The test is typically performed on the lower spine and hips.

What does bone density testing discover?

A bone density test is currently the only way to diagnose osteoporosis, a disease characterized by decreased bone density and quality. Osteoporosis and low bone density (osteopenia) increase the risk of bone fracture. Therefore, DEXA can be used to:

  • Diagnose osteoporosis, either before or after a bone fracture
  • Identify decreased bone density before you break a bone
  • Assess your risk of bone fractures
  • Monitor the success of osteoporosis treatment

When is bone density testing recommended?

Your healthcare provider will conduct a thorough health assessment to determine if you’re at risk for osteoporosis or decreased bone density. A bone density test may be considered if:

  • Further bone testing is recommended based on the results of a screening test such as a peripheral dual x-ray absorptiometry (pDXA), quantitative ultrasound (QUS), or peripheral quantitative computed tomography (pQCT)
  • You’ve lost height of at least ½ inch within a year
  • You’ve lost a total height of 1 ½ inches
  • You’ve had a break or bone loss in your spine
  • You are a woman aged 65 or older
  • You are a man aged 70 or older
  • You break a bone after age 50
  • You are a post-menopausal woman not taking estrogen
  • You have risk factors such as rheumatoid arthritis, chronic kidney disease, liver disease, type 1 diabetes, or a thyroid condition
  • You use medications that can cause bone loss, such as corticosteroids, anti-seizure medications, or high-dose thyroid replacement medications

How is bone density testing conducted?

Bone density tests are fast, easy, and noninvasive outpatient procedures. You will lay on a padded table while a mechanical imaging device passes over your body. You will be asked to stay still and perhaps hold your breath for a few seconds to ensure a clear image. The amount of radiation you’re exposed to is very small.

How are bone density test results interpreted?

Bone density test results are reported in T-scores and Z-scores:


Your T-score measures your bone mass compared to the bone mass of a healthy young adult of your gender.

  • -1 and above: Normal bone density
  • Between -1.1 and -2.5: Osteopenia (low bone density)
  • -2.5 and below: Osteoporosis


Your Z-score measures your bone mass compared to healthy adults of your age, gender, weight, and ethnicity. If your score is significantly higher or lower than normal, you may need further medical tests.


If you meet any of the above mentioned recommendations for considering bone density testing, give Peninsula Radiology a call at (757) 898-8830. We’d love to help!

What is a Bone Density Scan?

bone density Newport News VAbone density scan, or dual-energy x-ray absorptiometry (DEXA), is an enhanced type of x-ray used to measure bone density. The test is noninvasive and helps physicians to diagnose and treat conditions related to bone density. DEXA bone densitometry is a simple, painless procedure that  provides your physician with valuable data regarding your risk of developing a fracture.

Why is it used?

Bone density scans are commonly used to diagnose and track the effects of osteoporosis and other conditions that can cause bone loss. The DEXA test can identify conditions related to bone density and can be used to assess fracture risks. A DEXA test is recommended for many people, including (but not limited to):

  • women who are post-menopausal and not taking estrogen
  • a person with a personal or maternal history of hip fracture
  • a person who has experienced a fracture after only mild trauma
  • a person with type 1 diabetes, liver disease, kidney disease, or a family history of osteoporosis
  • post-menopausal women who are tall (over 5 feet 7 inches) or thin (less than 125 pounds)


This test requires very little preparation. Eat normally, but avoid taking calcium supplements for at least 24 hours before the examination. Wear comfortable clothing and avoid garments with metal (zippers, belts, buttons) as metal could interfere with the images from the x-ray.  Be sure to inform your physician if you have recently had a barium exam, been injected with any contrast material, or if there is any possibility that you could be pregnant as these could interfere with the test.


There are two types of machines for this procedure, a central device and a peripheral device. A central device, is used for testing the density of the hip and spine. During this test, the patient lies on a padded table and the machine is located below the patient with the image displayed above.

The peripheral device is used on the lower arm, wrist, finger, or heel. Each machine sends a beam of low-dose x-rays that will have energy peaks to calculate the bone density and display the information using a specialized computer software.


A radiologist, will interpret the results. The test is presented as one of two scores:

  • T score – This score will compare your results with that of a healthy adult. A score of +1 or -1 is considered normal while a score of -1 to -2.5 reflect low bone mass. Scores lower than -2.5 are indicative of osteoporosis with greater negative numbers showing the severity of the condition.
  • Z score – This score compares your bone density to what is considered normal for someone your age and body size. The Z-score is often misleading.

After tests have been completed and results analyzed, you doctor will consult with you about the best course of action. For any other questions about this procedure, please contact Peninsula Radiology Associates. We will be happy to provide you with the answers you need.