Utility of Contrast Enhanced Ultrasonography with Sonazoid in Radiofrequency Ablation (RFA) for Liver metastasis E. Goto 1 , S. Shiina 1 , R. Tateishi 1 , R. Masuzaki 1 , K. Enooku 1 , T. Sato 1 , J. Imamura 1 , T. Goto 1 , Y. Sugioka 2 , H. Ikeda 1,2 , H. Yoshida 1 , M. Omata 1 1 Department of Gastroenterology, University of Tokyo, 2 Department of Clinical Laboratory, Tokyo, Japan