Beyond DEXA: Other Bone Mineral Density Tests

What are other methods of measuring BMD?

There are small DXA scanners called peripheral DXA machines. Regular DXA machines have a standard reference (called NHANES III) that can be used for all machines no matter the manufacturer. However, peripheral DXA machines do not yet have a uniform reference standard for the normal peak young adult bone mass that can apply to all machines and all manufacturers. This is necessary for peripheral DXA to be ready for more widespread use. Efforts are in progress to make the peripheral DXA technique more standardized.

Quantitative computed tomography (QCT) can be used to assess BMD. A standard CT scanner is used in this method. However, the amount of radiation exposure is higher than with DXA and the cost is greater. For these reasons, QCT is not in general clinical use.

Ultrasound is a relatively new diagnostic tool to measure BMD. There is no radiation source with this procedure. An ultrasound beam is directed at the area being analyzed. The scattering and absorption of the waves allow for an assessment of bone density. The results are not as precise as with the other methods mentioned. This technique is relatively new and there is considerable research being conducted in this area. Since ultrasounds can easily be performed in a physician's office, this method may become valuable for screening larger populations if its accuracy becomes more refined.