Quantitative Analysis Of Pancreatic Exocrine Function Of Chronic Pancreatitis In Cat Models

ObjectiveTo make quantitative analysis of pancreatic exocrine function of minimal, moderate and advanced chronic pancreatitis using secretin-stimulated magnetic resonance cholangiopancreatography (s-MRCP) in cats.Preliminary investigation on the accuracy of evaluating pancreatic exocrine function using ultrasmall superparamagnetic iron oxide marked secretin-stimulated magnetic resonance cholangiopancreatography (USPIO-S-MRCP) in cats.MethodsForty cats were included in this study, including normal control group (n=8), experimental group with the ligation of pancreatic duct (n=32). MRCP on MR scanner was performed after secretin which was by marked USPIO stimulation on all cats. According to the histological analysis of the pancreas, all the cats were classified into normal CP, minimal CP, moderate CP, advanced CP. The increasing degree of fluid volume (FVID) in the region of interest which encompassed the stomach and small bowel on each image was measured, and they were compared between control group and experimental group, separately. Compared the irons which was stained by Prussian blue between control group and experimental group,separately.Results1. Six cats were sacrificed after one to two weeks of duct ligation in the CP group.In the left26cats,4cats had normal pancreas and22had chronic pancreatitis.including8cats with grade1,8cats with grade2, and6cats with chronic pancreatitis grade3. The successful rate of induction was68.75%(22/32) in the cats.The severity of CP was partially correlated to the duration after pancreatic duct ligattion.2. They were divided into four groups based on pathology, including eight normal cats and seven, five and three cats with grade I, II and III CP, respectively. The normal cats had normal pancreatic duct morphology and a good qualitative response to secretin, and the gastrointestinal fluid has had an obviously increasing after injecting secretin. There was a significant difference for the FVID between CP-0and CP-II, CP-0and CP-III, CP-I and CP-III. Although there were no significant difference between CP-0 and CP-I, CP-I and CP-II, CP-II and CP-III, the FVID was a trend down with worsening degrees of CP. Conclusion S-MRCP can be used to quantify pancreatic exocrine function by observing the FVID, which were correlated to the severity of CP.3. MRI was performed after administration of secretin marked by USPIO, there was a significant signal decreased. In Prussian blue staining, we can observer blue staining of iron in the nomal cats, there is no difference of blue staining iron in the severity of CP.Conclusion1. S-MRCP can be used to quantify pancreatic exocrine function by observing the FVID, which were correlated to the severity of CP.2. The secretin marked by USPIO caused signal decreases in the MR images which can evaluate the pancreatic exocrine function preliminary.