1. A non-transitory computer-readable storage medium storing computer executable instructions that when executed by a computer control the computer to perform a method for characterizing a ground glass (GGO) nodule in a region of lung tissue, the method comprising: accessing an image of a region of lung tissue; delineating a GGO nodule in the image; extracting a set of texture features from the GGO nodule; selecting a subset of texture features from the set of texture features; extracting a set of shape features from the GGO nodule; selecting a subset of shape features from the set of shape features; generating a phenotypic signature for the nodule; and controlling a computer aided diagnosis (CADx) system to generate a classification of the GGO nodule in the image based, at least in part, on the subset of texture features, the subset of shape features, or the phenotypic signature.