Central bone densitometry: what to expect from a DEXA scan

The scan uses low-dose X-rays and is non-invasive. It does not directly show bone pain or arthritis, and the result is interpreted alongside your age, medical history, medicines and any previous fractures.

Central refers to measurements taken at the central skeleton, most often the lumbar spine and hip. These areas matter because loss of bone strength there can have a major effect on mobility and independence. A scanning arm passes over you while you lie on a padded table; nothing is injected into the body.

A report may include a T-score, which compares your bone density with that of a healthy young adult, and a Z-score, which compares it with people of a similar age and sex. The clinician also checks whether arthritis, spinal changes, a prior operation or metal hardware could distort a measurement. A score alone does not determine every treatment decision.

Follow the imaging centre's instructions about calcium supplements, and wear clothing without metal fasteners if possible. Tell the team if you may be pregnant, recently had imaging that used contrast or barium, or have metal implants, spinal surgery or a hip replacement. These details may affect timing, positioning or which site is measured.

During the scan, keep still and follow the technologist's positioning instructions. Afterwards, you can usually return to normal activities. Review the report with the requesting clinician, who may discuss food sources of calcium, vitamin D, weight-bearing and strengthening activity, fall prevention, possible blood tests or medication according to your overall fracture risk.

A low bone-density result is generally handled through a planned follow-up rather than emergency care. Arrange a timely review if you have had a fracture after a minor fall, have lost noticeable height, or develop persistent new back pain, because these details may change the assessment.

Seek urgent medical assessment after a fall if you have severe hip or back pain, cannot stand or bear weight, notice a limb looks deformed, or develop new weakness, numbness, or loss of bladder or bowel control. These symptoms require assessment for an acute injury or pressure on nerves, regardless of a previous DEXA result.

Ask which body sites were measured, whether anything affected the image quality, how the T-score and Z-score apply to you, and whether another scan should be performed later on the same machine. You can also ask how your fracture history, medicines, balance and other health conditions influence the plan beyond the scan result.