BACKGROUND/AIMS: The Tanner-Whitehouse (TW) method for bone age determination has been the basis for many population studies and it is used in many clinics. However, TW bone age raters can differ systematically from each other. The aim of the study was to present a new standard version of TW bone age rating implemented by the automated BoneXpert method and calibrated on the manual TW stage ratings of the First Zurich Longitudinal Study.
SUBJECTS: Hand radiographs of 231 children born in 1954-1956 were recorded annually from an average age of 5-20 years. For validation, 76 X-rays of Tanner's original Gold Series from eight boys were used.
RESULTS: The root mean square deviation between manual and automated TW ratings in the Zurich data was 0.67 years for boys in the TW bone age range 5-15 years and 0.63 years for girls, 5-14 years. The new standard TW rating differs systematically from two previous TW versions of the automated method, based on different raters.
CONCLUSION: The new automated TW ratings show good accuracy relative to the manual ratings of the Zurich data and the Gold Series. There are significant differences between manual TW raters, an effect which is eliminated with the automated method.