Epiphyseal fusion assessment based on wavelets decomposition analysis

Epiphyseal fusion is a finding frequently analysed in hand wrist radiographs. It is tested in the bone age assessment, the gonadal dysgenesis, etc. The computerized fusion analysis is performed on an automatically selected region of interest containing the lower edge of epiphysis and the upper edge of metaphysis. In the analysis a wavelets decomposition approach is employed. The wavelets decomposition components are first subjected to a preliminary test which rejects the overexposed images whose analysis would not give reasonable results. This increases the accuracy of the algorithm and a chance for an unsupervised application. Then, a quantitative measure is found. Its value decreases while the epiphyseal fusion proceeds. The analysis yields an assignment of fusion to one of four stages: no fusion, early stage of fusion, advanced stage of fusion, and fusion completed. The results show that wavelets decomposition components may efficiently be applied to a texture analysis. (C) 1996 Elsevier Science Ltd.