Deep Learning Framework for Skeletal Age Classification from Pelvic Radiographs using K-fold Cross Validation and Stacking of CNN Models
Keywords:
Bone age, Deep learning, Ensemble, Fine-tuning, K-fold cross-validation, Pelvic X-raysAbstract
Recent technological developments in deep learning environments have improved bone age evaluation, making it easier and more exact than classic methods in forensic radiology. Deep convolutional neural networks are highly effective at detecting bone age; however, their complexity arises from the number of parameters they need, making them resource-intensive to run on CPUs. To address this, the proposed work utilizes the transfer learning approach to build a two-stage deep learning model based on pelvic radiographs, comprising a vital bone extraction model and an age assessment model. Initially, UNet model combined with Attention Gate extracted the pelvic girdle bones by filtering insignificant regions from pelvis X-rays. For age assessment, a smaller classifier network was first developed and evaluated using K-fold cross-validation. Subsequently, the two deep networks were built by layering the new ones to the existing framework. To enhance performance further, the outputs of both the classifiers were stacked using a dense layer called an aggregator. This meta-learner combined the strength of each model to make decisions on final prediction. The whole framework was validated to analyse its ability to categorize human age in the range of 0–19 years using the collected pelvic radiographs and achieved an average classification accuracy of 97.50%, precision of 98.25%, recall of 96.65%, and F1-score of 97.20%. Thus, the proposed framework can increase the accuracy of multi-classification tasks while leveraging the limited computational resources.
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