title: Microbubble-induced increase in ablation of liver tumors by high-intensity focused ultrasound.
abstract: We studied the possibility of using high-intensity focused ultrasound (HIFU) together with a microbubble agent to treat hepatocellular carcinoma. Development of liver tumors in rats was induced by administration of Dimethylnitrosamin (100ppm). Rats with liver tumors were anesthetized, underwent laparotomy, and were given the microbubble agent Levovist or saline intravenously. After the injection, the liver was exposed to HIFU for 30s (2.18MHz, 600W/cm(2), 40mm in diameter). Immediately after HIFU exposure, ultrasound images of the HIFU area were evaluated. Then the liver was excised and the volume of coagulated tissue was measured. The mean volumes of hyperechoic areas after HIFU were as follows (mm(3), Levovist versus saline: 355.3+/-180.7 versus 47.4+/-35.6, P<0.001, n=13). The volumes of liver tissue coagulated by HIFU were as follows (mm(3), Levovist versus saline: 275.3+/-120.0 versus 60.1+/-23.6, P<0.001, n=13). On microscopic examination of areas exposed to HIFU, implosion cysts were seen, and many cancer cells were found to have been destroyed completely (loss of cell membranes or nuclei). In conclusion, the microbubble agent Levovist can increase the volume of tissue coagulated by HIFU.
authors.affiliation: Department of Gastroenterology, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8655, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hanajiri
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Maruyama
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mitsui
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Watanabe
authors.forename: Masataka
authors.initials: M
authors.lastname: Sata
authors.forename: Ryozo
authors.initials: R
authors.lastname: Nagai
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kashima
authors.forename: Junji
authors.initials: J
authors.lastname: Shibahara
authors.forename: Masao
authors.initials: M
authors.lastname: Omata
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Matsumoto