猪正常胰腺的CT、MRI表现及多期增强扫描方案的研究

目的：探讨大动物猪正常胰腺的CT、MRI表现及多期增强扫描的最佳方案，为猪作为胰腺病模型动物提供参考资料。方法：健康幼猪10只，行CT平扫及薄层动态增强扫描，其中6只同时行MRI扫描，序列包括T1WI、T2WI、DWI、MRCP。扫描结束后10只猪均剖腹及离体观察胰腺的形态及位置，并与影像学表现对照。结果：①猪胰腺分为胰头及左、右两叶，呈“三叶草”形。其中左叶为胰腺的主体部分，其解剖位置、大体形态、胰周血管、胰实质密度、MRI T1加权像、T2加权像信号、弥散加权成像（DWI）信号及ADC值等均与人类胰腺十分相近；②MRCP显示猪的胰胆管系统与人不同，分别开口于十二指肠，相距约5—9cm；胆管较粗，直径约5～6mm，易显示；而胰管纤细，值径约1～1．5mm，生理状态下MRI对其显示欠佳；③螺旋CT多期增强扫描时间密度曲线与人类相似，但胰腺三期增强扫描即动脉期、胰实质期、门脉期最佳延迟时间较人早，分别为15s、35s、45s。结论：大动物猪胰腺的CT、MRI表现及多期增强扫描方案与人类有许多相似之处，可作为胰腺疾病影像学研究的理想平台。

Study of the CT and MRI features of normal pig's pancreas and the optimal protocol of multi-phase enhanced CT

Objective：To study the CT and MR/features and the optimal protocol of multi-phase enhanced CT of normal pig＇s pan- creas and compare them with human beings.Methods： CT plain scanning and thin-shce dynamic eullanced scanning were performed respectively in 10 tlealthy pigs. Six of them underwent MIlI at the same time, including TIWI, T2WI, DWI and MRCP sequences. All of the pigs were cuted to observe pig pancreas shape and position with naked eyes. The cr and MRI findings were compared with surgery. Results：（1）The pancreas of pig which liked ＂dover＂ was divided into three parts, pancreas head, left lobe and right lobe. The left lobe was the main part of pig＇s pancreas. It was resemble considerably to human being＇ pancreas, such as dissection location, general morphologic, the per-pancreatic vessels, CT density, MR/signals of T1WI,T2WI and diffusion-weighted imaging （DWI） and ADC value; （2） The images of pancreasticobiliary of normal pigs on MRCP were different from those of human being. It＇ s bile duct and pancreatic duct converged at the duodenum respectively. The bile duct was comparatively wider with diameter of 5 ～ 6mm, while the pancreatic duct was narrow with diameter of 1 ～1.5 mm and it was difficult to be shown by MRCP; （3） Multihase enhanced CT protocol： the results of enhanced CF scanning indicated that the time-density curve was similar with that of human beings. The optimal scanning protocol was： 15 s for arterial phase, 35s for the pancreatic parenchyma,45 s for tbe peripancreatic portal vein phase. Conclusion： The CT and MRI features and muhi-phase enhanced CT scanning protocols of pancreas of pigs are considerable similar with fllat of human beings. Therefore, the pig may be an ideal model of big animal in imaging research of pancreas diseases.