Quantifying "Information" Of Tumor CT Image Different Phases

I’m working with multiphase CT images of liver tumors. Visually we see better demarcation of tumors and intricate enhancement pattern within tumors on arterial phase vs portal venous phase.

Has anyone tried to use quantitative measurement for such an observation? Perhaps something as simple as a t-test vs some form of Shannon Entropy measurement using a histogram of the tumor voxels?