tokens: ROI : region of interest ; HU : Hounsfield Unit ; IH : intensity histogram ; FBS : fixed bin size ; FBN : fixed bin number ; IVH : intensity - volume histogram ; GLCM : grey level co - occurrence matrix ; NGTDM : neighborhood grey tone difference matrix ; NGLDM : neighbouring grey level dependence matrix ; GLSZM : grey level size zone matrix ; GLDZM : grey level distance zone matrix .