PURPOSE: To establish a preoperative protocol for ultrasonographically guided percutaneous radiofrequency (RF) ablation of large liver tumors that is based on mathematic models and clinical experience and to evaluate the role of this protocol in RF ablation. MATERIALS AND METHODS: A regular prism and a regular polyhedron model were used to develop a preoperative protocol for liver tumor ablation. This protocol enabled the authors to minimize the number of ablation spheres, optimize the overlapping mode, and determine the electrode placement process. One hundred ten patients with 121 liver tumors were treated by using this protocol. Sixty-nine patients had 74 hepatocellular carcinomas (HCCs), and 41 had 47 metastases to the liver (ie, metastatic liver carcinomas [MLCs]). Patients underwent follow-up helical computed tomography (CT) 1 month and every 2-3 months after RF ablation. Ablation was considered a success if no contrast enhancement was detected in the treated area on the CT scan obtained at 1 month. RESULTS: A total of 536 ablations were performed in the 121 tumors. The ablation success rate was 87.6% (106 of 121 tumors); the local recurrence rate, 24.0% (29 of 121 tumors); and the estimated mean recurrence-free survival, 17.1 months. Twenty-five patients underwent 38 re-treatments for local tumor recurrence. Major complications occurred in seven patients. Of these patients, only one, who had a tumor close to the colon, had a colon perforation 1 week after RF and required surgical intervention. CONCLUSION: The described protocol for treatment of large tumors had a success rate of 87.6% and a local recurrence rate of 24.0%.

PURPOSE: The purposes of this study were to investigate a treatment strategy to increase liver tumor necrosis and minimize complications with ultrasound-guided percutaneous radiofrequency (RF) ablation and to evaluate its therapeutic efficacy. MATERIALS AND METHODS: A total of 332 patients with 503 liver malignancies underwent RF ablation according to a mathematical protocol with adjunctive measures. In the 332 patients, 205 had 308 hepatocellular carcinomas (HCCs) with a mean largest diameter of 4.1cm and 127 had 195 metastatic liver carcinomas (MLCs) with a mean largest diameter of 3.9cm. In patients with HCC, 60 (29.3%) had stage I/II disease and 145 (70.7%) had stage III/IV disease. Depending on tumor size, shape, and location, a defined treatment strategy was adopted that consisted of a mathematical protocol, an individualized protocol, and adjunctive measures. The mathematical protocol was followed for tumors larger than 3.5cm. The individualized protocol was used for tumors located adjacent to the diaphragm, gastrointestinal tract, or gallbladder. Some adjunctive measures such as supplementary fine needle localization, local saline solution injection, and feeding vessel ablation were used to deal with different features of these liver tumors. Patients were followed regularly to assess treatment efficiency, and the tumor was considered to have early complete necrosis if no viability was found on enhanced computed tomography 1 month after RF ablation. RESULTS: In this series, the early necrosis rates were 95.8% for HCC (295 of 308 tumors), 94.9% for MLC (185 of 195 tumors), 91.3% for tumors larger than 3.5cm (189 of 207 tumors), 90.7% for tumors near the gastrointestinal tract (49 of 54 tumors), 91.5% for tumors near the diaphragm (86 of 94 tumors), and 90.6% for tumors near the gallbladder (48 of 53 tumors). The local recurrence rates were 10.7% for HCC (33 of 308 tumors) and 14.9% for MLC (29 of 195 tumors). The 1-, 2-, and 3-year overall survival rates were 89.6%, 69.4%, and 59.6%, respectively, for HCC and 80.3%, 52.8%,and 30.9%, respectively, for MLC. The 1-, 2-, and 3-year survival rates in 60 patients with stage I/II HCC were 93.7%, 87.1%, and 76.2%, respectively. The incidence of major complications was 1.4% (eight of 574 sessions), which included of three hemorrhages, four injuries to adjacent structures, and one case of needle tract seeding. CONCLUSION: In RF ablation of hepatic tumors, application of a proper protocol and adjunctive measures play important roles in improving tumor necrosis rate and minimizing potential complications.

Background The advent of second generation agent-SonoVue arid low mechanical index real-time contrast enhanced uhrasonography (CEUS) imaging have been shown to improve the diagnostic performance of ultrasonography in hepatocellular carcinoma (HCC). But no report has described the effect of high mechanical index (MI) post-CEUS This study aimed to investigate the value of post-CEUS in displaying tissue structures of HCC. Methods Seventy-six HCCs in 65 patients were included in the study Each patient undm~ent three scans, high-MI (MI: 0.15-1.6) pre-contrast ultrasound, low-MI (Mi: 0.04-0.08) CEUS with contrast agent SonoVue, and high-MI post-contrast ultrasound, which was performed within 3 minutes after CEUS The size, boundary, echogenicity, internal echotexture arid posterior acoustic enhancement of the HCCs in the conventional scans before and after CEUS were evaluated According to pathological evidence, diagnosis rates of pre-contrast, CEUS arid post-contrast scans were determined arid compared The potential mechanism of post-contrast ultrasound imaging was also discussed. Results Compared with pre-contrast, post-contrast ultrasound showed improvement in image quality in most HCCs: twenty-six (34.2%) more lesions showed well defined margins and fourteen (18.4%) more nodules showed halo sign; twenty-three (30.3%) lesions demonstrated enlarged in sizes; changes in echogenicity were seen in 30 lesions(39.5%): eighteen(23.7%) more lesions showed heterogeneeity and 20 (26.3%) more lesions showed "mosaic" or "nodule-in-nodule" sign: twelve (15.8%) more lesions showed posterior acoustic enhancement Post-contrast ultrasound showed increased diagnostic accuracy of 93.4% (71/76), compare with 88.2% (67/76) of CEUS alone. Conclusions High-MI post-contrast ultrasound utilizes harmonic signals during the rupture of microbubbles, and significantly improves the display of echo-characteristics of HCCs in ultrasound images, which adds diagnostic values for CEUS Post-contrast ultrasound could play an important role in tissue characterization, and may be included in CEUS protocols.

目的：探讨射频消融(RFA)规范化治疗及综合措施对提高肝肿瘤疗效的应用价值。方法：302例计476个肝脏恶性肿瘤行RFA治疗，应用规范化治疗方案及附加治疗方法，总结疗效。原发性肝癌(HCC)181例，282个癌灶，肿瘤大小平均412cm。肝转移癌(MLC)121例，194个癌灶，肿瘤大小平均319cm。根据肿瘤大小、形态及邻近膈肌、胆囊、胃肠等不同位置，采用相应的规范化方案及个体化方案相结合治疗；重视相邻重要结构区域的消融布针方法及操作技巧；应用辅助定位、局部注水、加强肿瘤血管消融等附加方法综合治疗。结果：综合应用以上方法，RFA后1个月增强CT或超声造影显示肿瘤灭活率HCC为9517%（270/282），MLC为9418%（184/194）；邻近肠管肿瘤为9111%（51/56），邻近膈肌肿瘤为8815%（69/78），邻近胆囊肿瘤为9413%（49/52）。随访3～57个月，局部复发率HCC为1013%（29/282），MLC为1414%（28/194）。患者1年、2年、3年的生存率HCC为8716%、6714%、5816%；其中50例Ⅰ～Ⅱ期肝癌的生存率分别为9017%、8519%、7317%。MLC为8714%、4812%、2513%。并发症占212%（13/583）；分别为出血5例，采用局部消融、全身用药等处理措施；肠穿孔1例，对邻近肠管肿瘤采用治疗后延长禁食时间等措施进行预防。余7例为邻近脏器结构轻度损伤，无与射频治疗相关死亡。结论：采用规范化RFA治疗方案及适宜的个体化治疗方案，重视附加方法的应用，有助于提高肝肿瘤灭活率；掌握主要并发症的类型及对应预防措施，是提高疗效及推广RFA治疗的重要环节。

目的：分析≤2cm微小肝癌的超声造影增强模式，探讨超声造影新技术对微小肝癌的早期诊断价值。方法:应用新型超声造影剂SonoVue及CnTI实时灰阶超声造影匹配成像技术（CEUS）对392例肝脏局灶性病变行超声造影检查，其中经穿刺活检确认肝硬化合并≤2cm肝细胞癌（HCC），并有病理组织学分类诊断的36例38灶为本文研究对象。全部病例造影后即刻或半个月内均行穿刺活检或手术病理检查。最终确诊为中分化癌22个灶，高分化癌12个灶，透明细胞癌4个灶。结果:造影前常规超声仅对16个灶（42.1%）作出恶性诊断或可疑恶性。造影后38个HCC灶动脉期均不同程度增强；其中中分化癌22个灶均发生快速增强，并在实质期快速消退，呈典型的“快进快出”HCC增强模式;高分化癌12个灶中有9个灶（75.0%）呈“快进慢出”模式；透明细胞癌4个灶中1个灶呈“快进快出”，1个灶呈“快进慢出”模式，2个灶呈“轻度慢进慢出”模式。根据CEUS后增强表现，本组76.3%（29个灶）被确认为恶性，18.4%（7个灶）诊断为可疑恶性，另2个≤1.5cm灶（513%）造影增强不典型，未能获得定性诊断。结论:超声造影新技术对肝硬化背景下不同组织类型微小肝癌增强模式的认识为提高微小肝癌的诊断率提供依据。初步结果显示，新型超声造影可作为CT等影像学诊断的互补手段，在小肝癌的早期诊断中发挥重要作用，值得重视推广。