There is not a feature alone which can be used for discriminating tissue in medical images. A number of different features may be used instead which may help in the correct discrimination. Such features are for instance, texture features which can be extracted from the liver and the rest of the organs. If you have a large number of images then you can extract features from both areas under investigation. Then you may perform statistical tests or comparisons. One such test is the Wilcoxon ranksum test which tests significant statistical difference between two populations. If your test shows lower statistical significance p

Thank you Christos P. Loizou for your answer.