慢性胰腺炎的猫模型制作及磁共振影像表现

目的 制备猫慢性胰腺炎(CP)模型,观察其MRI与MRCP的影像学表现.方法 32只猫按数字表法随机分为对照组及制模后3、5、7周组.采用胰管不全结扎法制备CP模型,术后3、5、7周行MRI平扫及MRCP检查,观察胰腺形态,测量胰管直径及感兴趣区(ROI)的T1信号强度值(Tls),计算同层胰腺及肝脏Tls比值.结果 制模的24只猫中存活19只,其中15只形成CP,病理证实轻、中、重度CP分别为7、5、3只,制模成功率为62.5％.在MRI上,猫的正常胰腺显示清晰,T1加权像信号强度高于肝脏,T2加权像信号强度低于肝脏；在MRCP图像上,4只正常猫显示主胰管,胰管最大径(0.79±0.18)mm,并可见胰管及胆总管共同开口于十二指肠降部.正常胰腺及轻、中、重度CP感兴趣区的rTls值分别为1.03±0.06、0.95±0.08、0.90±0.10、0.80±0.11,各CP组与正常对照组间差异均有统计学意义(t=2.18,P＜0.05；t =2.89,P＜0.05；t =4.63,P＜0.01)；胰管最大径分别为(0.79±0.18)、(0.95±0.24)、(1.26±0.31)、(2.67±0.71)mm,中、重度CP组与正常对照组间差异均有统计学意义(P＜0.05或＜0.01).结论 胰管不全结扎可制备猫的CP模型.猫的胰腺解剖形态、CP的MRI及MRCP表现与人类相似.

Animal model of chronic pancreatitis in cats and MR imaging features

Objective To establish an animal model of cat with chronic pancreatitis (CP),and to investigate the imaging features of MRI and MRCP of normal pancreas and CP.Methods Thirty two cats were randomly divided into control group ( n =8 ) and experimental group ( n =24) ( 3,5,7 weeks after model establishment,eight cats in every group).Partial ligation of the pancreatic duct was used to induce chronic pancreatitis.All cats underwent MRI plain scanning,MRCP scanning 3,5,and 7 weeks after modeling to observe the pancreas morphology.The values of T1 signal intensity of pancreas were obtained using a region of interest (ROI) method,and the diameter of pancreatic duct was measured.The ratios of T1 signal intensity ( rT1 s) between pancreas and liver were calculated and compared.Results Nineteen of 24 cats survived,and 15 cats developed CP,and the pathologic examinations showed mild,middle,severe CP developed in 7,5,3 cats,suggesting a successful model induction rate of 62.5％.The pancreases of cats were displayed clearly on MRI.The signal intensity of pancreas was higher than that of liver on T1WI,whereas it was lower than that of liver on T2WI.Meanwhile,there were four cats' pancreatic ducts were shown on MRCP,the maximum diameter of pancreatic duct was (0.79 ±0.18) mm,and the opening orifice of pancreatic duct was located at descendant duodenum with common bile duct.The rT1 s of ROI of normal pancreas,mild,middle,severe CP was 1.03 ±0.06,0.95 ±0.08,0.90 ±0.10,0.80 ±0.11,and the difference among these groups was statistically significant (t =2.18,P ＜ 0.05 ; t =2.89,P ＜ 0.05; t =4.63,P ＜ 0.01).The maximum diameter of pancreatic duct was (0.79 ±0.18),(0.95 t0.24),( 1.26 ±0.31),(2.67 ±0.71 )mm,and maximum diameter of pancreatic duct of middle,severe CP was significantly different when compared with that of normal pancreas ( P ＜ 0.05 or ＜ 0.01 ).Conclusions The method of partial ligation of pancreatic duct can induce CP in cats.The normal pancreas and CP of cats are similar with human with respect to anatomy,morphology,MR and MRCP imaging features.