3.0T MRI Study Of Human Pancreatic Cancer In A Nude Mouse Model

This study adopted Siemens Magnetom Trio Tim 3.0 Tesla superconductive MRI,enhancement scanning by means of injecting contrast agent intraperitoneally and clinical breast coil first time.Took nude mouse as experimental materials,to perform MRI study of early human pancreatic cancer in a heterotopic nude mouse model,which was divided into three parts.Part One:Select the coil for nude mouse MRI scanningObjective:To select the best coil for nude mouse MRI scanning.Materials and Methods:Adopting Siemens Magnetom Trio Tim 3.0 Tesla superconductive MRI,head coil,neck coil,knee coil and breast coil,using same parameters,fifteen mice were scanned by four coils to acquire TSE-T₁-weighted and T₂-weighted transverse axial images.The SNR of liver,right kidney,right-posterior part muscle of back was calculated.The quality of images was analyzed.Result:Using same scanning condition,the SNR of breast coil's image was higher than the other's,the SNR of knee was higher than head and neck's,the SNR of head was approximate to neck's.Conclusion:Adopting same parameters,the SNR and picture quality of breast coil were the best,which were superior to the others.It was illuminated that anatomic structure of mouse could be clearly displayed by integrating of clinical application 3.0 Tesla MRI with breast coil. Part Two:Establish the nude mouse model of human pancreatic cancerObjective:The nude mouse model of human pancreatic cancer was established,and its histological characteristics of the transplanted tumor was studied.Materials and Methords:The animal model of human pancreatic cancer was developed by injecting human pancreatic cancer cells Panc-1 subcutaneously into the nude mice.The growing rate and volume of tumor were recorded every week.After seven weeks the animals were executed,the histological characteristics of the transplanted tumor and the neovascular status were studied by immunohistochemical staining.Results:The successful rate from transplantation was high(86.7 %,13/15)with rapid growing of the tumour.The vasculature was very rich in the tumor.Pathological examination showed that it was coincident to low grade adenocarcinom(?).Conclusion:This method was very simple and reproducible.The animal models are suitable for,studying the pancreatic cancer in vivo.Part Three:3.0T MRI early features of human pancreatic carcer in a heterotopic nude mouse modelObjective:The nude mice model of human pancreatic cancer were established,and their 3.0T clinical MRI early feature associated with histological characteristics of the transplanted tumor was studied. Materials and Methods:The animal model of human pancreatic cancer was developed by injecting human pancreatic cancer cells Panc-1 subcutaneously into the nude mice.The growing rate and size of tumors were recorded.The nude mice bearing tumors were sampling at 10 days after postinoculation of the cells for MRI plain and contrast enhancement scanning.The successive scanning was performed within 2 min and at 3,6,9 min postinjection of Gadodiamide intraperitoneally.Early MRI features of the tumor and its surrounding tissues were observed. Pathologic examination was done after MRI scanning.Results:(1)Eighteen of 20 nude mice were found total 22 tumors;(2) The successful rate of transplantation was 90%(18/20)with rapid growing of the tumors.Pathological examination showed that it was coincident to low grade adenocarcinoma.(3)The early MRI findings of the tumors were uniformly slightly hypo-intensity(50%,11/22), iso-intensity(32%,7/22)or hyper-intensity(18%,4/22) onTSE-T₁WI,uniformly(91%,20/22)or unevenly(9%,2/22) hyper-intensity on TSE-T₂WI;during post-contrast dynamic scanning,all the tumors were demonstrated gradually obviously enhancement.Conclusion:By integrating of Clinical 3.0T MRI,breast coil and enhancement scanning,the human pancreatic cancer cells Panc-1 subcutaneously implanted tumor mode in nude mouse smaller than 5mm can be observed;Tumors could be significantly intensified at 3min postinjection of the contrast agent intraperitoneally.Enhancement scanning could provide more biologic information,so as to confirm that intraperitoneal injection was a feasible mean for MRI enhancement scanning of nude mouse bearing tumor,thus can help finding an early,noninvasive,sensitive and specificities way for the diagnosis of pancreatic cancer under internal,forthcoming condition.