sentences:  vessels).Gadolinium contrast is not necessary as it does not give additional information over noncontrast studies, though some current researchers argue that dynamic, contrast-enhanced MRI may help determine the amount of necrosis within the tumor, thus help in determining response to treatment prior to surgery.Computed axial tomography (CT) can also be used to define the extraosseous extent of the tumor, especially in the skull, spine, ribs, and pelvis.