Medical instruments for use in determining plaque lipid content as indicator of plaque vulnerability; for determining the size of stented vessels; for determining stent area; for determining spatial ablation; for preparing veins and pre-arterializing veins for CABG procedures; for controlling blood pressure; for unloading the heart; treatment of aortic aneurysm; for preventing migration and endoleaks types I and II; and for GI organ remodeling