肝退变结节癌变及超声下微波治疗后的MRI随访观察

MRI of dysplastic nodules and cancerous nodules of liver after microwave therapy under ultrasound guidance:a follow-up observation

目的:探讨肝退变结节癌变及超声下微波治疗后MRI的随访价值。方法:对经临床和病理证实的16例肝退变结节(DN)和其中5例小癌变结节超声引导下微波治疗前后的MRI资料进行回顾性分析。所有病例行常规横轴面梯度回波序列,同、反相位T1WI、抑脂T2WI及三期增强扫描。结果:16例DN中,同、反相位T1WI上呈等信号者4个,呈稍高信号者12个,抑脂T2WI上均呈相对等信号-低信号;增强方式呈"缓升速降"型14例(88%),15例可见不规则网状纤维分隔强化;5例肝退变结节癌变,均表现为T1WI上等、高信号基础上出现低、等信号,T2WI低信号基础上出现等、高信号,强化方式呈"速升速降"型3例,呈"缓升速降"型2例。所有癌变结节经微波治疗后1周内MRI平扫显示结节区信号范围扩大,在T1WI和T2WI上均呈高、低混杂信号,增强检查病灶不强化4例,病灶局部呈"速升速降"型1例。结论:肝退变结节定期MRI随访能够早期检测和观察肝退变结节癌变,并有助于癌变结节微创介入治疗术后的疗效观察。

Objective：To evaluate the role of MR imaging follow up in dysplastic nodules （DN） and stepwise carcino genesis of hepatocellular carcinoma （HCC） and changes after percutaneous microwave therapy. Methods： MR imaging data of 16 patients with 16 DN including 5 cancerous nodules proved by clinic and pathology were reviewed retrospectively,and the 5 patients with cancerous nodules accepted MRI examination before and after microwave therapy. All the examinations were performed using a 1.5T MR unit with SE and GE sequences including in/ out phase TI weighed and fat saturated T2 weighed imaging,and triphasic enhanced scanning. Results： Out of 16 patients with DN, 4 were isointense and 12 were slightly hyperintense on in/out phase T1 WI,On fat saturated T2WI,all DN were isointense or hypointense; 14 DN showed synchronous enhancement with normal hepatic parenchyma （ Ⅱ type） on gadolinium enhanced scans, i. e. 88 % （14/16）, while irregular reticular fibrous septum in 15 DN showed slight enhancement during delayed phase,i, e. 93 % （15/16）. Of 5 patients with carcinogenesis of HCC,all were isointense and hypointense on in/out phase TlWI, On fat saturated T1WI, cancerous nodules were slightly hyperintense or heterogeneous intense. Among the 5 patients 3 showed obvious enhance ment during arterial phase,decreased during the portal phase （type Ⅰ ） and 2 showed synchronous enhancement with nor-mal hepatic parenchyma （type Ⅱ ） on gadolinium enhanced scans. MR examination within one week after percutaneous mi crowave therapy, 4 showed iso-or hyperintence on T1 WI, iso-or hypointence on fat saturated T2 WI, and no enhancement on dynamic scanning,one patient showed similar findings to the previous MR imaging performed before microwave therapy in some parts of the tumor. Conclusion： MR imaging provides insight in various pathways of stepwise carcinogenesis of develo ping HCC in cirrhosis,This may facilitate early detection and better observation of patients for follow-up, it can be used to assess the efficacy of liver microwave therapy.