MRI Showed Changes In The Pancreaticobiliary Duct:Usefulness For Differentiating Mass Forming Chronic Pancreatitis From Pancreatic Carcinomas

Objective To investigate the value of MRI showing the change of the pancreaticobiliary duct system in the differentiation of mass forming chronic pancreatitis(MFCP)and pancreatic carcinomas(PC).Methods Analyze the MRI data of 23 MFCP patients and 49 PC patients in our hospital from February 2016 to May 2020.All patients undergo routine sequence and MRCP scanning in the MRI examination equipment,and compare the morphological differences of the main pancreatic duct,branch pancreatic duct and common bile duct between the two groups of patients.Combined the identification points to establish a Combined diagnostic model,use the Logistic regression equation to calculate the combined predictor,and compare the diagnostic sensitivity and specificity of the combined diagnostic model with any single identification method.Results The characteristics of the pancreaticobiliary duct in the MFCP group include:(1)The pancreatic duct can penetrate the lesion area(73.91%);(2)Side branches dilated at uncinate process(78.26%),and the cystic dilatation of side branches in MFCP were significantly more than PC(34.78% vs 10.20%,P<0.05);(3)The distal end of the common bile duct was conical stenosis(52.17%)or normal(39.13%),and abrupt truncation was rare(8.70%).The characteristics of the pancreaticobiliary duct in the PC group include:(1)"double duct sign" is more common(63.27%);(2)the pancreatic duct is often truncated at the mass(61.22%);(3)the distal end of common bile duct is often truncated(65.31%);(4)The main pancreatic duct diameter/pancreatic parenchymal width is larger than that in the MFCP group(0.36±0.16 vs 0.27±0.17,P<0.05),and the ratio ≥0.32 is helpful for the diagnosis of PC.There was no statistically significant difference in the degree of expansion of the main pancreatic duct and branch pancreatic ducts and the morphology of the main pancreatic duct between the two groups.The five most characteristic identification points,including double duct sign,pancreatic duct penetrating sign,main pancreatic duct diameter/pancreatic parenchyma width,uncinate partial branch pancreatic duct expansion,and distal common bile duct truncation,are combined to calculate the joint diagnosis model.Use the Logistic regression equation to calculate the diagnostic sensitivity and specificity of the combined diagnostic model and draw the ROC curve.The area under the ROC curve is 0.914,and its 95% confidence interval is(0.844～0.983).The sensitivity of the combined diagnosis model is 83.3%,and the specificity is 91.3%,which is greater than the remaining five independent indicators.The combined diagnosis model has good differential diagnosis ability.The Hosmer-Lemeshow statistics(P=0.751)show that the predicted value and the observed value are not significantly different,so the model fits well.Conclusion MRI shows that pancreaticobiliary duct change plays an important role in distinguishing MFCP and PC.Combined with changes in the pancreaticobiliary system can improve the accuracy of the differential diagnosis of the two disease,and has reference significance for clinical diagnosis.