体外高功率聚焦超声破坏肝组织的实验研究

High intensity focused ultrasound extracorporeal ablation of liver tissues in rabbits *

目的探讨体外高功率聚焦超声（ＨＩＦＵ）无损伤破坏兔肝组织的有效性和可行性．方法体外ＨＩＦＵ照射采用频率１１ＭＨｚ，声功率７５０Ｗ／ｃｍ２，连续超声波照射时间为２０ｍｉｎ．动物兔１６只随机分为两组：单纯体外ＨＩＦＵ照射组（Ⅰ组，ｎ＝８）和肝内碘化油注射＋体外ＨＩＦＵ照射组（Ⅱ组，ｎ＝８）．两组又根据超声波入路途径不同，各再分为肋间隙治疗组（ｎ＝４）和肋下治疗组（ｎ＝４）．结果无论超声波通过肋间隙或是肋下途径照射，肝内均发现有超声杀伤病灶（发生率为１００％）．Ⅱ组病灶体积（ｃｍ３）显著大于Ⅰ组（分别为１９±０５和０６±０３，Ｐ＝０００４）．通过肋间隙途径照射，易致肺、肋间隙和膈肌损伤，而通过肋下治疗则易致胃损伤体外ＨＩＦＵ无损伤破坏肝组织或肿瘤在技术上有潜在应用价值。

AIM To determine the technical feasibility of extracorporeal high intensity focused ultrasound (HIFU) to ablate liver tissues. METHODS HIFU was administered with a focused 1 1MHz transducer with a peak intensity of 750W/cm 2 for a continuous exposure duration of 20min. Sixteen rabbits were divided into two groups: group Ⅰ ( n =8) received HIFU alone and group Ⅱ ( n =8) received injection of iodized oil into the liver combined with HIFU. Both groups Ⅰ and Ⅱ were randomly divided into two subgroups of 4 rabbits each according to the difference of ultrasonic beam approaching, intercostal space or subcostal. RESULTS Sonoablated lesions in the liver were found in all treated animals, with an occurrence rate of 100%, with the ultrasonic beam either through intercostal space or subcostal. The volume (cm 3) of sonolesion in group Ⅱ was larger than in group Ⅰ, (1 9±0 5 vs 0 6±0 3, P =0 004). In the meantime, complications occurred through intercostal treatment such as the damage of lung, intercostal space tissue and diaphragm, while the damage of stomach was prone to be induced through subcostal therapy. CONCLUSION Extracorporeal HIFU is feasible to ablate liver tissues technically and iodized oil might enhance the effect of HIFU .