钆喷替酸葡甲胺-脂质体在兔MRI淋巴成像的应用研究

目的 研究钆喷替酸葡甲胺(Gd-DTPA)脂质体载体的淋巴组织靶向增强效果.材料与方法采用乙醇诱导法制备包裹Gd-DTPA的交错融合脂质体.将12只新西兰兔以数字表法随机分为对照组和反应性增生组,每组6只.反应性增生组采用兔大腿肌肉和腰窝皮下注射蛋黄乳胶的方法建立胭窝、腹股沟和腹膜后淋巴结三组相连续的反应性增生模型.分析各组淋巴结在Gd-DTPA脂质体增强前后的MRI特征,并采用配对t检验进行比较.结果 Gd-DTPA脂质体平均粒径2.2μm,平均包封率为82%,平均载药量为53%.平扫时两组腹膜后淋巴结大小有差异(t=164.21,P<0.01),而信号强度在T_1WI和脂肪抑制T_1WI上均无差异(P值均>0.05).Gd-DT-PA脂质体增强后,腘窝和腹股沟淋巴结在15 min时达到最大强化,SNR与平扫时相比差异有统计学意义(t值分别为76.32和48.39,P值均<0.05).腹膜后淋巴结强化较轻,约在30 min时达到最大强化,但SNR与平扫时相比差异无统计学意义(t=0.57,P>0.05).结论 Gd-DTPA可包裹于脂质体载体内,并可以用MRI显示载体淋巴组织靶向增强效果,为下一步鉴别肿瘤转移性淋巴结与反应性增生淋巴结打下了良好的基础.

Application of Liposomal Gadolinium-Diethylenetriamine Pentaacetic Acid in the Magnetic Resonance imaging of rabbit Lymph Nodes

Objective To synthesize a novel liposome loaded with gadolinium and to explore its application in the magnetic resonance imaging of the rabbit lymph nodes in vivo.Materials and Methods The interdigitation-fusion method are adopted to synthesize the Liposomal Gd-DTPA.Twelve New Zealand rabbits were divided randomly into reactive hyperplasia group and control group with 6 in each.Reactive hyperplasia lymph node animal models were established by injected egg yolk emulsion into flank and hindlegs of six rabbits.All twelve rabbits underwent MR scanning were performed before and after subcutaneous administration of Liposomal Gd-DTPA.The signal of popliteal lymph nodes,inguinal lymph nodes and retroperitoneal lymph nodes were analyzed using t test.Results The mean diameter of liposomal Gd-DTPA was 2.2 μm.The mean encapsulation efficiency and loading capacity of Gd-DTPA were 82%,51.23% respectively.On pre-enhancement MR images,the size of the normal and reactive hyperplasia retroperitoneal lymph nodes had significant difference(t=164.21,P=0.000),while the signal intensity on T_1WI and T_1WI FS images had no significantdifference(P>0.05).After administration of liposomal Gd-DTPA,a significant increase occurred in the signal intensity of popliteal lymph nodes and inguinal lymph nodes with the peak at the 15th minute(P<0.05).However,the signal intensity of retroperitoneal lymph nodes did not increase significantly.Conclusion Liposome modified with Gd-DTPA is an ideal positive MR contrast agent of lymph nodes in MR lymphography.