Auto-detection of non-isolated pulmonary nodules connected to the chest walls in X-ray CT images

In this paper, we develop an auto-detection method of non-isolated pulmonary nodules for computer-aided diagnosis (CAD) of lung cancers using X-ray CT images. An essential core of the method is to transform the non-isolated nodules connected to the walls of the chest into isolated ones that can be detected more easily by CAD systems developed previously. To this end, an active contour model is proposed to extract the lung area from the original CT image. The proposed model can solve the local optimum problem of the contour model by using anatomical features of the lung in X-ray CT slices. Some experimental results demonstrate the usefulness of the proposed method by using clinical CT images.