同步辐射X线相衬成像对裸鼠胰腺癌的早期诊断

Early diagnosis of pancreatic cancer in a nude mice model on synchrotron radiation X-ray phase contrast imaging

目的通过建立裸鼠胰腺癌模型,结合磁共振成像(magnetic resonance imaging,MRI),探讨同步辐射X线相衬成像技术对胰腺癌的早期诊断。方法 32只nu/nu雌鼠,采用数字表法随机分为A、B两组:A组(n=24)为人胰腺癌细胞PANC-1胰腺原位移植瘤组,即于胰腺被膜下注射108×2μL单细胞悬浮液; B组(n=8)为空白对照组,即于胰腺被膜下注射2μL 0. 9%(质量浓度)氯化钠注射液。再根据术后1、2、3、4周处理时间的不同,将A、B两组分为4个亚组,即A1、A2、A3、A4(n=6)和B1、B2、B3、B4(n=2)。术后分别行MRI扫描、肿瘤标本相衬成像及病理学检查。结果①A组术后平均成瘤率73%(16/22),术后4周成瘤率最高,达到100%,成瘤率随观察时间的延长而升高,二者之间存在线性趋势关系(χ2线性趋势=4. 718,P=0. 030);病理组织学检查为胰腺低分化腺癌。②同步辐射X线相衬成像可显示直径为0. 5 mm的胰腺原位肿瘤,早期(两周)的灵敏度和特异度达到100%,明显高于MRI扫描(P=0. 029)。结论 PANC-1细胞原位移植是建立裸鼠胰腺癌模型的可靠方法;与MRI相比,同步辐射X线相衬成像能发现胰腺癌微小病变,有可能为胰腺癌的早期诊断提供了一种全新的技术手段。

Objective To explore the diagnostic value of synchrotron radiation X-ray phase contrast imaging compared with magnetic resonance imaging(MRI)in early diagnosis of pancreatic cancer with an orthotopic xenograft nude mice model of pancreatic cancer.Methods Thirty-two female nude mice were divided into 2 groups of 4 subgroups randomly,subgroups were labeled A1,A2,A3,A4(n=6)and B1,B2,B3,B4(n=2)as the different intervals at 1,2,3,and 4 weeks postoperatively,respectively.108 cells/m L×20μL PANC-1 cell suspension was injected into pancreatic capsula of group A but 20μL sterile saline was injected in the group B.MRI scans were performed at 1,2,3,and 4 weeks postoperatively and the specimens were excised from nude mice and fixed in 10%formalin immediately.Synchrotron radiation X-ray phase contrast imaging was performed followed by histopathological examination.Results①Low grade adenocarcinoma was confirmed with pathology,and the average rate of tumorigenesis in group A was 73%(16/22),and the rate was the highest after 4 weeks,which was 100%.With the time passing,the rate of tumorigenesis increased with the linear trend test(χ2=4.718,P=0.030).②The image of tumor with a diameter of 0.5 mm in pancreas was observed with synchrotron radiation phase contrast imaging.The sensitivity and specificity of the early(two weeks)reached 100%,significantly higher than that of magnetic resonance imaging(P=0.029).Conclusion PANC-1 cells injected into pancreatic capsula was a reliable method for establishment of pancreatic cancer model.Compared with MRI,synchrotron radiation contrast imaging could detect tiny lesions of pancreatic cancer,which may provide a new method for early diagnosis of pancreatic cancer.