Bone Mineral Density

A DEXA bone assessment sends two low-dose X-ray beams through a selected region and estimates how much mineral is present. The result is usually reported in grams per square centimetre. Because it is an areal measurement, bone size and scan geometry can influence the number; it is not a direct three-dimensional measurement of bone strength.

Reports often include a T-score or Z-score in addition to the absolute value. These are comparisons with reference populations, but they use different reference frames and are not interchangeable. Age, sex, scan site, hardware, software, positioning, and image artefacts all belong to the interpretation.

Bone mineral density is one component of skeletal assessment. It does not capture every feature of bone architecture, turnover, fall exposure, or personal history. Serial comparison is most useful when the same site and compatible equipment and analysis are used, because apparent movement can otherwise reflect methodology rather than biological change.

Whole-body and site-specific scans should also be distinguished. A body-composition scan may report bone mineral content across the body, while a diagnostic bone-density assessment emphasizes defined skeletal sites and standardized analysis. Similar words on the reports do not make these outputs interchangeable.

When serial scans are compared, the facility may use a least-significant-change value based on measurement precision. This helps distinguish a difference large enough to exceed expected technical variation from a small numerical shift that may reflect ordinary scan variability.

Related Previvo services: DEXA Scan Winnipeg | Previvo.