超顺磁性纳米氧化铁颗粒淋巴结成像及其与病理超微结构的比较  

Lymph Node Image with Ultrasmall Superparamagnetic Iron Oxide and Comparison with Pathological Result

作　　者：薛华丹[1] 雷晶[1] 李琢[1] 王德田[2] 周炜洵[2] 戴威[3] 金征宇[1] 

机构地区：[1]中国医学科学院北京协和医学院北京协和医院放射科,北京100730 [2]中国医学科学院北京协和医学院北京协和医院病理科,北京100730 [3]中国医学科学院北京协和医学院基础医学研究所电镜室,北京100005

出　　处：《中国医学科学院学报》2009年第2期139-145,I0003,共8页Acta Academiae Medicinae Sinicae

基　　金：国家高技术研究发展计划(863项目)(2007AA02Z400)~~

摘　　要：目的研究不同性质淋巴结超顺磁性纳米氧化铁颗粒(USPIO)的增强磁共振特征,探讨其与淋巴结超微结构的关系。方法36只健康新西兰兔随机分为炎症组及肿瘤转移组,兔足垫注射完全弗氏佐剂,用于建立腘窝淋巴结的炎性增生模型;兔后小腿肌肉接种VX2瘤株,用于建立腘窝肿瘤淋巴结转移模型。两组建模后动物均经静脉注射90μmolFe/kg的USPIO,于注射前及注射后24h分别行磁共振成像(MRI)扫描观察淋巴结信号强度及T2值变化并计算强化率,扫描后取出腘窝淋巴结行HE染色、普鲁士蓝染色及电镜切片,观察淋巴结超微结构的变化、铁颗粒在淋巴结内的分布特征,分析病理显微结构与淋巴结强化的关系。结果炎症组36枚淋巴结表现为不同程度的反应性增生,肿瘤转移组共26枚淋巴结为肿瘤转移性。平扫时炎性增生的淋巴结和肿瘤转移性淋巴结的T2信号强度差异无显著性,USPIO强化后,炎性增生淋巴结中心T2信号强度明显降低,肿瘤转移淋巴结则表现为均匀而不明显的T2信号下降,二者淋巴结强化率分别为57.39%和29.45%,差异具有显著性(P<0.01)。HE染色、普鲁士蓝染色及电镜切片显示淋巴结内的USPIO铁颗粒主要分布于淋巴结髓索结构内,副皮质区及皮质区巨噬细胞相对较少,与MRI图像相对应;电镜检查显示USPIO颗粒均存在于巨噬细胞的胞饮泡内。肿瘤转移淋巴结中,4枚正常淋巴结结构丧失,19枚仍存在部分淋巴结结构但其内含USPIO铁颗粒的巨噬细胞减少且巨噬细胞内铁颗粒数目减少,3枚仅见小片状包膜下转移灶。结论良恶性淋巴结USPIO强化特征与淋巴结的超微结构特别是巨噬细胞在结内的分布及其功能状态有较密切关系,可能影响USPIO对淋巴结性质的诊断准确性。Objective To assess the characteristics of enhanced magnetic resonance image with ultrasmall superparamagnetic iron oxide （USPIO） in the inflammatory and tumor metastatic rabbit model, and explore its relevance with histologic ultrastructural findings. Methods Totally 36 New Zealand white rabbits were randomly divided into lymphadenitis group and metastatic group. Complete Freund＇s adjuvant was injected into the bilateral dorsal footpads of 18 rabbits to set up ipsilateral lymphadenitis model. The other 18 rabbits received a subcutaneous implantation of VX2 tumor cell suspension （ 1.5 × 10^7 cells/ml） in both thighs to set up metastatic lymph node model. Magnetic resonance scan were performed 24 hours before and after USPIO （90 μmol Fe/kg） injection, T2 values of each lymph node were measured and lymph node T2 enhancement rate was calculated as well. HE staining, Prussian blue staining, and electronic microscopy were performed to observe the pathological microstructure changes and the distribution of the iron particle in lymph node. Relationship between lymph nodes USPIO enhancement and its microstructures were further analyzed. Results Thirtysix lymph nodes in lymphadenitis group showed different degrees of reactive hyperplasia. Twenty-six lymph nodes in metastatic group were invaded by tumor cell. Non-enhanced scan showed mild difference between T2 signal intensity of the two pathological lymph node types. After USPIO enhancement, inflammatory lymph nodes showed distinct T2 signal reduction at the center, signal reduction. Enhancement rate of benign and and metastatic lymph nodes showed homogenous and faint T2 malignant lymph nodes were 57.39% and 29.45% respectively （P 〈0.01 ）. HE staining and Prussian blue staining indicated USPIO particles located mainly in the macrophages at inflammatory lymphatic medulla, while paracortical area and cortical area contained relatively much less USPIO particles due to less macrophages distribution. MRI findings were correlated with the pathological resu

关 键 词：超顺磁性纳米氧化铁颗粒 淋巴结 磁共振成像 

分 类 号：R814.42[医药卫生—影像医学与核医学]