MR扩散加权成像评价兔VX2肝肿瘤射频消融疗效的实验研究  

Experimental Study on the Therapeutic Effects of Radiofrequency Ablation of Hepatic VX2 Carcinoma in the Rabbit Model with MR Diffusion-Weighted Imaging

作　　者：梁惠宏[1,2] 张耀军[1,2] 陈敏山[1,2] 蔡木炎[1,3] 谭国胜[4] 冯仕庭[4] 张亚奇[1,2] 李锦清[1,2] 

机构地区：[1]华南肿瘤学国家重点实验室,广东广州510060 [2]中山大学肿瘤防治中心肝胆科 [3]中山大学肿瘤防治中心病理科 [4]中山大学附属第一医院放射科

出　　处：《实用放射学杂志》2010年第11期1670-1674,共5页Journal of Practical Radiology

摘　　要：目的 通过对兔VX2肝肿瘤模型作动物实验,探讨MR扩散加权成像（diffusion-weighted imaging, DWI）在评价射频消融疗效的可行性与可靠性.方法 9例兔VX2肝肿瘤模型做射频消融术（radiofrequency ablation, RFA）,治疗后1周做常规MRI检查确定肿瘤平面后,选择b值（扩散敏感度）为100 s/mm2,300 s/mm2和1000 s/mm2分别做水扩散加权成像扫描,与病理作比较分析正常肝组织、残留肿瘤灶和消融坏死灶的DWI图、表观扩散系数（apparent diffusion coefficient,ADC）差异.结果 由于受患兔呼吸与心跳影响,DWI图像均存在不同程度伪影.以DWI图像上正常肝组织信号作为对比,对应于病理观察到的存活肿瘤组织区域在DWI图像上表现为更低信号,而消融坏死灶区域表现为高信号.而在选定平面所重建的ADC图像上则刚好相反,存活区域色彩鲜明,而消融坏死区域色彩暗淡.正常肝组织、存活肿瘤组织与消 融坏死组织的ADC值（单位：×10-3mm2/s）分别为1.658±0.866、2.011±0.925、0.709±0.511（b＝100 s/mm2）;1.242±0.651、1.436±0.425、0.529±0.387（b＝300 s/mm2）;0.819±0.357、1.136±0.217、0.558±0.332（b＝1000 s/mm2）.在同一b值下,ADC值由高到低依次为存活肿瘤组织、正常肝组织与消融坏死组织,而存活肿瘤组织与消融坏死组织在同一b值下均存在显著性差异;随着b值的升高,不同组织的ADC值普遍降低,在b值分别为100 s/mm2和1000 s/mm2时,同一组织的ADC测量值也存在统计学差异（消融坏死组织除外）,消融坏死组织在不同b值下测量ADC值无显著性差异.结论 MR扩散加权成像能从微观、功能成像的角度区别消融坏死灶与肿瘤残留灶,是有发展潜力的新型RFA评价手段,但图像质量有待改进.Objective To explore the feasibility and reliability of MR diffusion--weighted imaging （DWI） in assessing the tumor cell death after radiofrequency ablation （RFA） in a rabbit model with hepatic VX2 carcinoma. Methods 9 rabbit models with hepatic VXz carcinoma were treated by RFA, MR scan was performed 1 week after RFA followed by diffusion--weighted imaging at the plane of the tumors, and the b values were set at 100 s/mm2 , 300 s/mm2 and 1000 s/mm2 respectively. After the DWI scan, the animals were sacrificed and the tumors were removed to do hiostopathological examination. Images of DWI were analyzed and the apparent diffusion coefficient （ADC） of normal liver parenchyma, residual viable tumor and necrosis tissue induced by RFA according to histopathological finding were compared. Results Macro--movement including breath and heart beat of the rabbit brought artifacts to DWI images. It appeared to be low MR signal intensity for residual viable tumor and high for necrosis tissue compared with the signal intensity of normal liver parenchyma on DWI images. Bright color was seen for residual viable tumor and gray color for necrosis tissue in ADC images. The ADC values in normal liver parenchyma, residual viable tumor and necrosis tissue were （1. 658±0. 866）×10^-3mm^2/s, （2.011±0.925）×10^-3mm^2/s, （0.709±0.511）×10^-3mm^2/s（b=100 s/mm2）;（1.242±0.651）×10^-3mm^2/s, （1. 436±0. 425） ）×10^-3mm^2/s, （ 0. 529±0. 387）×10^-3mm^2/s（b=300 s/mm^2 ） ;（0. 819±0. 357） ×10^-3mm^2/s, （1. 136 0.05）. The ADC value for necrosis at different b value level showed no statistical significance （P〈0.05）. Conclusion As a func- tional MR imaging, DWI can help to differentiate the necrosis tumor tissue from residual viable tumor by comparing their ADC value. The quality of the DWI images was under improvement.

关 键 词：动物 肝 肿瘤 射频消融 磁共振成像 

分 类 号：R735.7[医药卫生—肿瘤] R-332[医药卫生—临床医学]