The BoneXpert Method for Automated Determination of Skeletal Maturity

Abstract

Bone age rating is associated with a considerable variability from the human interpretation, and this is the motivation for presenting a new method for automated determination of bone age (skeletal maturity). The method, called BoneXpert, reconstructs, from radiographs of the hand, the borders of 15 bones automatically and then computes "intrinsic" bone ages for each of 13 bones (radius, ulna, and 11 short bones). Finally, it transforms the intrinsic bone ages into Greulich Pyle (GP) or Tanner Whitehouse (TW) bone age. The bone reconstruction method automatically rejects images with abnormal bone morphology or very poor image quality. From the methodological point of view, BoneXpert contains the following innovations: 1) a generative model (active appearance model) for the bone reconstruction; 2) the prediction of bone age from shape, intensity, and texture scores derived from principal component analysis; 3) the consensus bone age concept that defines bone age of each bone as the best estimate of the bone age of the other bones in the hand; 4) a common bone age model for males and females; and 5) the unified modelling of TW and GP bone age. BoneXpert is developed on 1559 images. It is validated on the Greulich Pyle atlas in the age range 2-17 years yielding an SD of 0.42 years [0.37; 0.47] 95% conf, and on 84 clinical TW-rated images yielding an SD of 0.80 years [0.68; 0.93] 95% conf. The precision of the GP bone age determination (its ability to yield the same result on a repeated radiograph) is inferred under suitable assumptions from six longitudinal series of radiographs. The result is an SD on a single determination of 0.17 years [0.13; 0.21] 95% conf.

Automatic determination of Greulich and Pyle bone age in healthy Dutch children

“…The new computerized approach for BA assessment (BoneXpert, v1.0; Visiana, Holte, Denmark, www.Bone Xpert.com) consists of three computational layers [9]:…”

“…1 The first two layers, which are by far the most complex, were developed from the radiographs of Danish and Fig. 1 BoneXpert reconstructs the borders of 15 bones (metacarpals 2 and 4 are reconstructed in order to determine bone mass by radiogrammetry) and estimates the GP BA for 13 bones as indicated Belgian children (age range 7-17 years), supplemented by radiographs from various sources to extend the age range to 2.5-19 years for boys and 2-18 years for girls; in total 1,678 images [9]. BoneXpert's accuracy is recognized to be poor for boys above 17 years and girls above 15 years, so the intended age range for the clinical use of BoneXpert v1.0 is GP BA 2.5-17 years for boys and 2-15 years for girls, and the performance tested in this work was therefore restricted to these age ranges.…”

“…The previous version of BoneXpert (v0.9) has been described [9]. This version did not use the Erasmus and Tübingen data to adjust layer C, but only the GP atlas.…”

Bone age and height prediction of young Brazilian goalkeepers

“…The difference between biological age and chronological age will define if the individual is on time mature(chronological age~biological age), early mature(chronological age<biological age) or late mature(chronological age>biological age). After this procedure it was estimated the predicted height through the Bone Expert protocol made by the platform available in the domain Bone Expert.com [9] .…”

Bone Age Classification Using the Discriminative Generalized Hough Transform

“…However, the classification still has to be carried out manually. A fully automatic method is given by the BoneXpert-System [3], which determines the age according to the method of GP or TW using active appearance models and regression. Fischer et al [4] developed another fully automatic method using content-based image retrieval.…”