Bone Density DEXA Scans

A Dual-energy X-ray absorptiometry scan (also known as a bone densitometry, DEXA or DXA scan) is a low-dose form of an X-ray. It is used to check the density (strength) of your bones to assess your risk of osteoporosis, a condition which can cause bone weakness or bone loss, making you prone to breaks and fractures.

A bone density DEXA scan is most commonly carried out on the spine or hip, but other body areas may be included. You'll be asked to lie on a flat bed with a scanning arm above you. The arm will move over the area being scanned:

Spine - The spine is checked for bone weakness and bone thinning. Your legs will be supported on a padded box, which lets your pelvis and lower spine (lumbar) lie flat.

Hip - The hip is scanned as it has a higher break and fracture risk from osteoporosis. Your foot will be positioned in a brace or strap to rotate the hip inward for imaging.

Forearm, hand or wrist - Your forearm may be scanned if you have a hip replacement, or cannot lie flat for a spine scan. The same machine or smaller peripheral devices may be used on the hand, wrist or forearm.

Each section of the spine takes between 10-30 minutes to scan, and a whole spine MRI can take up to 60 minutes.

Depending on where your back pain is coming from, you may only need a scan on a single section of your spine (e.g. lumbar spine, or thoracic spine). The pre-scan clinician consultation included with your scan will ensure you’ve selected the right area for your symptoms.

Your DEXA report shows your bone density via 'T-score', comparing you to a young, healthy adult, and possibly a 'Z-score', comparing you to an adult of your same demographic. The T-score values are:

• +1 to -1: Normal bone density
• -1 to -2.5: Lower bone density or osteopenia
• -2.5 and below: Osteoporosis

T-scores in osteopenia or osteoporosis ranges simply flag a potential risk for osteoporosis and fractures, and may not be a cause for concern. Your clinician will offer advice and guidance about your results and the next steps.

If you have arthritis, are postmenopausal or experienced early menopause, broke a bone after a minor fall, or have a family history of hip fractures, a DEXA scan might be suggested due to a potentially higher osteoporosis risk. Typically, these scans are done every two years, as it can be difficult to measure significant changes at shorter intervals.

DEXA bone density scans are the best method to diagnose osteoporosis, with results given as a T-score to compare your bone density to healthy adults or other people in your demographic. For diagnosing bone cancer, arthritis or other musculoskeletal disorders, a CT or MRI would usually be recommended instead. Nevertheless, a DEXA scan may form part of your treatment or monitoring plan.