Microbubble-induced increase in ablation of liver tumors by high-intensity focused ultrasound.
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.
Hanajiri
Kazuyuki
K
Department of Gastroenterology, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8655, Japan.
Maruyama
Toshiyuki
T
Kaneko
Yukio
Y
Mitsui
Hiroshi
H
Watanabe
Shunsuke
S
Sata
Masataka
M
Nagai
Ryozo
R
Kashima
Takeshi
T
Shibahara
Junji
J
Omata
Masao
M
Matsumoto
Yoichiro
Y