DEXA bone density scan

What it means

A DEXA scan (short for dual-energy X-ray absorptiometry) is an imaging test that measures bone mineral density using two low-dose X-ray beams. It is not the same kind of scan as a CT or MRI ordered to look for tumors or organ problems — its entire purpose is to check how much calcium and mineral is packed into your bones, most commonly at the hip and lower spine, since these are the sites most predictive of fracture risk and most often affected by osteoporosis.

Why it appears on a CT or MRI report

You'll typically encounter the term "DEXA" as a standalone scan report of its own rather than buried inside a CT or MRI report, though radiologists sometimes reference prior DEXA results when interpreting spine or hip imaging done for other reasons, since bone density context can help explain findings like a vertebral compression fracture. A DEXA report itself centers on your T-score, which compares your bone density to that of a healthy young adult, and sometimes a Z-score, which compares you to others your own age and sex.

What it usually means

DEXA scans are the standard screening tool for osteoporosis, recommended for most women starting around age 65, earlier for those with risk factors, and for some men and younger adults with conditions or medications that weaken bone. A T-score of -1.0 or above is considered normal bone density. A score between -1.0 and -2.5 indicates osteopenia, a lower-than-ideal but not yet osteoporotic bone density that often calls for lifestyle changes and monitoring. A score of -2.5 or below meets the definition of osteoporosis, which raises fracture risk and often prompts a conversation about calcium, vitamin D, weight-bearing exercise, and sometimes bone-strengthening medication.

When to follow up

Discuss your T-score and Z-score results with your doctor, who will weigh them alongside your age, fracture history, family history, and other risk factors like smoking or long-term steroid use to decide on next steps. Osteopenia usually means a repeat scan in a couple of years to watch the trend, while osteoporosis usually prompts a more active treatment plan. A new fracture from a minor fall or bump, especially in the hip, wrist, or spine, deserves prompt medical evaluation regardless of when your last DEXA scan was done.

A plain-language way to picture it

Think of your bones like the wooden beams holding up a house. Over the decades, beams can quietly lose density and become more porous, even though the house still looks the same from the outside. A DEXA scan is like a specialized sensor that checks how solid those beams really are without needing to tear open the walls. A high reading means the beams are sturdy; a lower one means it may be time to reinforce them before they're put under real strain.