Quantitative evaluation of humeral head defects by comparison with the opposite side

For many years, orthopedic surgeons have evaluated the size and shape of humeral head defects by comparing CT images of the right and left sides. However, this diagnostic method is strongly dependent on the clinical experience of the physician. It is therefore necessary to develop a quantitative method for diagnosing and evaluating humeral head defects. In this report, we propose a computer-aided quantitative diagnostic method for evaluating humeral head defects by comparing the shapes of the right and left humeral heads in three-dimensional (3-D) images reconstructed from multislice CT images based on the assumption that the humeral heads exhibit mirror symmetry. An active contour model, histogram and discrimination analysis, and a superimposition technique were developed to compare the differences between 3-D images of the right and left humeral heads. The results showed that the proposed method is very useful for the automatic extraction of the size and shape of humeral head defects. (author)