Determination of lung regions on chest ct images with diffuse lung diseases by use of anatomical structures and pulmonary textures

To analyze diffuse lung diseases based on chest region computed tomography (CT) imaging by using a computer-aided diagnosis (CAD) system, it is necessary to first determine the lung regions subject to analysis. The lung regions can be selected relatively easily for healthy individuals, by applying a threshold. Selecting an area by using a threshold-based method can be difficult when dealing with lungs with diffuse lung diseases, owing to the abnormal opacities that characterize the diseases. Trials for determining the lung regions were conducted in this study, through texture analysis and machine learning, by narrowing down the lung regions to rough regions, and by referring to ribs and the diaphragm. This method can be used for determining lung regions for analysis of diffuse lung diseases.