Does mirror imaging a radiograph affect reliability of age assessment using the Greulich and Pyle atlas?

Age estimation is routinely undertaken by comparing radiographs of the individual in question to published reference samples of individuals of known age. This study examines the reliability of age estimation utilizing the Greulich and Pyle atlas in relation to both left- and right-hand/wrist radiographs and explores whether reversing right-hand/wrist radiographs, so that they are in the same anatomical orientation as those images used in the atlas affects reliability. A total of 403 left-hand/wrist radiographs and 415 right-hand/wrist radiographs were age assessed using the Greulich and Pyle atlas. Analysis showed that there is no significant loss in reliability when radiographs of the right hand (women R(2) = 0.887 and men R(2) = 0.907) are utilized instead of the left (women R(2) = 0.939 and men R(2) = 0.940) or when they are assessed as mirror images to those printed in the reference atlas (reversed female left hand R(2) = 0.929 and reversed male left hand R(2) = 0.931).