Animal model of chronic pancreatitis in cats and MR imaging features / 中华胰腺病杂志

ABSTRACT

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.