The central goal is the development of new MRI techniques, or new combinations of established techniques, for distinguishing tumors from normal tissue or inflammation. This is an important clinical diagnostic problem when diagnosing or staging cancer. While conventional MRI can often detect tumors, it is often difficult to distinguish them from imflammation or edema. A secondary goal is relating MR images to tumor vascular patterns and tumor oxygenation. Tumor oxygenation is an important factor in determining the response to radiation therapy. These goals will be approached by combining the information obtained from images of protons, fluorine, and sodium. The proton images will be used for their anatomical detail. The fluorine images will be of fluorinated blood substitutes and will dilineate vascular anatomy and measure the vascular oxygen tension. The sodium images will be of endogenous sodium which in biological systems shows two components of T2 decay. Chemical shift reagents will be used to identify the intra and extracellular components. We will determine whether the short T2 component can be used to distinguish tumors from edema. The work will be done in a variety of animal tumors of known vascularity and radiosensitivity. If successful, the techniques can be transferred to human imaging and should lead to improved tumor diagnosis.
