超顺磁性氧化铁粒子增强MRI在骨肿瘤动物模型中的实验研究

Experimental Study of SPIO-Enhanced Magnetic Resonance Imaging in the Bone Tumor Model

目的评价超顺磁性氧化铁粒子(SPIO)增强MRI在正常兔骨髓成像及兔的骨肿瘤模型中的应用价值。材料与方法新西兰兔12只(2.0～2.5 kg)随机平均分为正常组和肿瘤组。分析正常组注射SPIO(200μmol/kg)前后骨髓6 h～16天的信号变化;分析肿瘤组中髓内肿瘤及周围正常骨髓在SPIO增强前后的MRI信号特征,并与病理检查对照。结果SPIO增强后正常组骨髓信号强度下降,24 h后骨髓负性强化达到高峰,第16天骨髓基本恢复正常信号;肿瘤组髓内肿瘤的信号强度在SPIO增强后保持不变,肿瘤周围骨髓信号明显降低。结论静脉注射SPIO后正常骨髓可较长时间保持负性强化水平;SPIO增强MRI能够提高骨髓内肿瘤的显示效果。

Objective To evaluate value of SPIO enhancement magnetic resonance imaging of normal bone marrow in New Zealand White Rabbits and assess the application of SPIO in a bone tumor model of rabbits. Materials and Methods 12 New Zealand Whites Rabbits were randomly assigned into two groups including normal and bone tumor group. The MR signal intensity of bone marrow was measured before and 6hr to 16d after injection of SPIO into an ear vein at a dose 200μmoL/kg in normal group. The MR signal intensity of tumor and surrounding normal marrow was analyzed before and 24hr after injection SPIO into an ear vein at a dose 200μmol/kg, then the inoculated tibias were dissected free for the aim of pathological study. Results In normal group ： After administration of SPIO, the SI reduction of the normal bone marrow was significant and lasted almost 15 day, and the maximal reduction of SI occurred at 24hr. In. tumor group： On enhanced images, the SI of the bone tumor remained unchanged, while the normal marrow reduced significantly. The contrast between normal bone marrow and bone tumor increased significantly. Conclusion The bone marrow enhanced MR image may be optimally obtained 6 -24hr after injection ASPIO into an ear vein. SPIO may be used to improve the contrast between normal bone marrow and bone tumor and may allow distinction of normal marrow from bone tumor by means of their different pathological activities.