人胰腺癌裸鼠皮下移植瘤模型MRI表现与病理对照研究

MRI Features and Pathology of Human Pancreatic Cancer Subcutaneously Implanted Tumor Model in Nude Mice

目的探讨人胰腺癌裸鼠皮下移植瘤磁共振成像（MRI）检查技术及其影像学表现的病理机制。方法建立人胰腺癌Patu8988细胞株裸鼠皮下移植瘤模型20只,细胞接种后2、4、6、7、8周随机抽取4只荷瘤鼠,进行大体观察、MRI检查和病理检查。大体观察荷瘤鼠和肿瘤的生长后进行MRI扫描,MRI平扫后,腹腔注射钆贝葡胺后4min行增强扫描,观察肿瘤影像学表现和周围组织情况;MRI检查后处死荷瘤鼠,解剖瘤灶,进行病理学研究,并与MR图像进行对照。结果肿瘤接种成功率为100%。2周时瘤灶T1WI和T2WI信号较均匀,4~8周时瘤灶T1WI呈均匀等信号或稍高信号,T2WI呈不均匀混杂信号,增强扫描瘤灶不均匀强化,以瘤灶周缘强化明显,内可见斑片状无强化区,随着肿瘤的生长,其内无强化区逐渐扩大。结论常规MR扫描技术能对胰腺癌皮下移植瘤的发生发展进行动态观察,移植瘤MRI表现可从病理学角度进行解释。

Objective To investigate the MRI features of human pancreatic cancer subcutaneously implanted tumor in nude mice and the pathomechanism of the MRI features. Methods Twenty nude mice were subcutaneously injected with human pancreatic cancer cells Patu8988 to establish the animal model. Every 4 mice were randomly sampled at 2, 4, 6, 7, and 8 weeks after inoculation of the cells to conduct gross observation, MR scanning, and pathological examination. After gross observation, the bearing tumors were scanned by MR and enhanced MR（4min after Gd-BOPTA injection）, and then the mice were sacrificed for pathological examination. MRI findings were compared with pathological findings. Results The successful rate of inoculation was 100%. The signal of two-week-old tumors showed iso-intensity on T1 WI and T2 WI, the signal of four- to eight-week-old tumors showed iso-intensity or slight hyper-intensity on T1 WI, and mix-intensity on T2 WI. The tumors were intensified at 4min postinjection of the contrast agent.The edge of the tumors was intensified more than the center and the no-reinforcement area was observed in the center. Along with the growth of tumor,the no-reinforcement area enlarged gradually. Conclusion Routine MRI can be used to dynamically observe the transplanted tumor of pancreatic cancer,and the MRI features of implanted tumors have corresponding pathological findings.