Multicentre European COMAC-BME study on the standardisation of bone densitometry procedures.

26 European centres participated in a concerted research action Biomedical Engineering: Quantitative Assessment of Osteoporosis. With a newly designed European spine and forearm phantom, the stability, accuracy, precision of dual energy absorption (DXA) and quantitative computer tomography (QCT) densitometry machines have been evaluated. Marked and clinically significant differences were found between brands and between techniques. Cross-calibration formulae have been made and normative data evaluated for different regions (spine, femoral neck, femoral trochanteric and forearm). A general fit for all data obtained from different machines was established.The cross-calibration formulae will allow a sensitivity analysis to assist the choice of equipment for clinical management of different categories of patients with bone disease. The present results obtained with an internationally accepted European spine and forearm phantom can now serve to stimulate the manufacturers to improve the comparability of bone measurements between machines.