Computer-Aided Detection of Solid and Ground Glass Nodules in Thoracic CT images using two independent CAD systems

In computed tomographic lung cancer screening, both solid and ground glass nodules are regularly encountered. Ground glass nodules may or may not have a solid component and it has been shown that they have a much higher chance of being malignant in comparison to solid nodules. Computer-aided detection (CAD) systems designed for solid nodules perform poorly on detection of ground glass nodules, and vice versa. Therefore, a CAD system that combines the output of two prototype CAD systems aimed at detection of ground glass nodules and solid nodules, respectively, could lead to efficient detection of the entire spectrum of lung nodules in chest CT scans. In this study, we combine the output of two prototype CAD systems and show results on a data set of 73 CT examinations containing both solid and ground glass nodules. The main category of nodules which are found by both CAD systems are ground glass nodules with a solid component.