Measurement of bone mineral density (BMD) by quantitative computed tomography (QCT) uses most standard CT scanners with software packages that allow them to determine bone density in the hip or spine. This technique is unique in that it provides for true three-dimensional imaging and reports BMD as true volume density measurements.
The advantage of QCT is its ability to isolate the area of interest from surrounding tissues. It can, therefore, localize an area in a vertebral body of only trabecular bone leaving out the elements most affected by degenerative change and sclerosis.
Peripheral Quantitative Computed Tomography (pQCT) devices are QCT instruments that have been adapted for measurements at peripheral sites such as the wrist.