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.
Technically speaking, an intrusion is any formation of intrusive igneous rock; rock formed from magma that cools and solidifies within the crust of the planet. In contrast, an extrusion consists of extrusive rock; rock formed above the surface of the crust.