title: Hyperecho in ultrasound images during high-intensity focused ultrasound ablation for hepatocellular carcinomas.
abstract: High-intensity focused ultrasound (HIFU) is a noninvasive method that can cause complete coagulation necrosis without requiring the insertion of any instruments. The hyperechoic grayscale change (hyperechoic region) is used as a sign that the treated lesion has been completely coagulated. The purpose of this study was to evaluate the first hyperechoic region during treatment using HIFU ablation according to various conditions, such as the sonication power, the depth of the tumor from the surface of the skin, and the shield rate. HIFU treatment was performed in 20 patients. The HIFU system (Chongqing Haifu Tech, Chongqing, China) was used under ultrasound guidance. Complete coagulation was achieved in 17 cases. Hyperechoic region were detected after HIFU ablation in 17 patients. The size of the hyperechoic region at a depth of >50 mm was significantly smaller than that at a depth of ≤50 mm. The number and power of the sonications for areas at a depth of >50 mm were significantly larger than those for areas at a depth of ≤50 mm. The number and power in cases with a shield rate of 31-60% were significantly larger than those in cases with a shield rate of 0-30%. When the shield rate was 0%, a hyperechoic region occurred, even when a maximum sonication power was not used. In all three cases with tumors located at a depth of greater than 70 mm and a shield rate of larger than 60%, a hyperechoic region was not seen. In conclusion, hyperechoic regions are easy to visualize in cases with tumors located at a depth of ≤50 mm or shield rates of 0-30%.
authors.affiliation: Gastroenterological Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama, Kanagawa 232-0024, Japan. fukuhiro1962@hotmail.com
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukuda
authors.forename: Kazushi
authors.initials: K
authors.lastname: Numata
authors.forename: Akito
authors.initials: A
authors.lastname: Nozaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kondo
authors.forename: Manabu
authors.initials: M
authors.lastname: Morimoto
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Tanaka
authors.forename: Ryu
authors.initials: R
authors.lastname: Ito
authors.forename: Masao
authors.initials: M
authors.lastname: Ohto
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ishibashi
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Oshima
authors.forename: Ayao
authors.initials: A
authors.lastname: Ito
authors.forename: Hui
authors.initials: H
authors.lastname: Zhu
authors.forename: Zhi-Biao
authors.initials: ZB
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000628:therapy*; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D008297:Male; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014464:Ultrasonic Therapy; D014463:Ultrasonography / Q000379:methods*