Results: The correlation between actual BD and BD normalized to the reference was improved by
changing PP from clinical (R2 ผ 0.96) to minimal (R2 ผ 0.98). Higher tube voltage [kilovolt (kV)] improvedthe correlation further. Even for clinical PP, average standard deviation (SD) was 0.97 mmAl, much smaller than the change of 2.51 mmAl clinically observed in early OA, which implies the feasibility of BD measurements on digital radiographs.
Conclusion: Changing PP and acquisition settings in clinical practice can have profound effect on
outcome. If done with care, accurate BD measurement is feasible using plain digital radiography.
_ 2011 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.