[Reproducibility of bone density measurements of the distal radius using a high resolution special scanner for...

Reliable determination of bone loss in the skeletal system depends on the accuracy of bone mineral density (BMD) measurements. We investigated short-term and long-term accuracy in vitro and in vivo using a new, commercially available special-purpose computed tomography scanner (Single Energy Peripheral QCT: XCT 900, Stratec FRG) for BMD measurements. Using a phantom, the long-term accuracy (3 months) in vitro yielded a coefficient of variation (cv) of 0.18%. Repeated measurements in 37 patients showed excellent reproducibility, with a cv of 0.71%. The differentiation into groups of low, average and high trabecular bone density demonstrated values of 0.61%, 0.59% and 0.98%, respectively for cv. BMD determination with pQCT is a high-precision method. It seems to be suitable for detection of trabecular bone loss in the range of the annual decrease in bone mass, provided the forearm is positioned with maximum care.