多时间点动态增强MRI评价裸鼠皮下移植瘤的实验研究

目的：探讨多时间点动态增强MRI在评价裸鼠皮下移植瘤模型中的价值。方法裸鼠20只，建成BGC-823细胞株皮下瘤模型，随机分成A、B两组进行磁共振成像，应用3.0TMR对肿瘤先进行 T1WI、T2WI成像，A组通过尾静脉注入磁共振造影剂Gd-DTPA后再进行T1WI增强扫描，分别在4min、30min、1h、2h各个时间点进行扫描。B组通过尾静脉注入生理盐水进行对照，同样在以上4个时间点进行T1WI扫描，采用信号增强率评价每个时间点图像的增强效果。结果 T2WI肿瘤呈高信号，境界清楚，肿瘤信号欠均匀。T1WI肿瘤呈等信号或稍低信号，信号尚均匀。在4min、30min、1h、2h各个时间点，A组信号增强率分别为2.8%、4.7%、3.5%、1.5%，B组信号增强率分别为0.1%、0.2%、0.1%、0.1%，A组信号增强率明显高于B组（t=4.302，P=0.001；t=6.872，P=0.000；t=5.458，P=0.000；t=2.701，P=0.002）。结论3.0T磁共振可以客观、清楚显示裸鼠皮下移植瘤，通过尾静脉注射造影剂对皮下瘤有较好的增强效果，多时间点动态增强MRI显示皮下瘤在注射造影剂后30min信号增强率最高。

Objective To evaluate the dynamic contrast-enhanced MRI in detecting subcutaneous transplanted tumor in nude mouse.Methods Twenty nude mouses with subcutaneous transplanted tumor were randomly assigned into A and B groups and underwent T1weighted imaging、T2 weighted imaging with a 3.0 Tesla MR scanner. The nude mouses of Group A were underwent T1weighted imaging after contrasted with Gd-DTPA injection at 4min、30min、1h、2h. As a control group, the nude mouses of Group B were underwent T1weighted imaging after injected with saline via tail vein at 4min、30min、1h、2h. The effect of contrast was evaluated by signal enhancement rate.Results The tumors were uneven hyperintensity on T2WI and hypointensity on T1WI. The signal enhancement rates of group A were separately 2.8%、4.7%、3.5%、1.5% and the signal enhancement rates of group B were separately 0.1%、0.2%、0.1%、0.1%. The signal enhancement rates of group A were significantly higher than those of group B（t=4.302, P=0.001;t=6.872,P=0.000;t=5.458,P=0.000;t=2.701,P=0.002）.Conclusion MR imaging can evaluated ＊＊ transplant tumor accurately, objectively by 3.0 Tesla MR scanner. Good enhancement effect can be acquired by tail vein injection. The signal enhancement rate of the transplant tumor can achieve the highest at 30 minute after injecting contract using dynamic contrast-enhanced MRI.