A covenant or agreement between two or more persons, with a lawful consideration or cause. Jacob. A deliberate engagement between competent parties, upon a legal consideration, to do or abstain from doing, some act. Wharton.
Enhancing means that the mass brightens up with contrast, meaning that there is a lot of blood vessels feeding the mass. These are imaging terms that radiologists use to describe a picture. <br /><br /> Inhomogeneous means that the whole mass does not look the same; the best I can describe is that it looks speckled. For example, a cyst that is filled with fluid will be homogeneous. Every part of what's inside the cyst will look identical, because it's just fluid in there.
A catalyst in the same phase (usually liquid or gas solution) as the reactants and products is called homogeneous catalyst. A catalyst that is in a separate phase from the reactants is said to be a heterogeneous, or contact, catalyst. Contact catalysts are materials with the capability of adsorbing molecules of gases or liquids onto their surfaces. An example of heterogeneous catalysis is the use of finely divided platinum to catalyze the reaction of carbon monoxide with oxygen to form carbon dioxide.