CT Imaging And Texture Analysis In The Differential Diagnosis Between Mass-forming Pancreatitis And Pancreatic Cancer

Objective To explore the value of CT imaging findings and texture analysis parameters in the differentiation of mass-forming pancreatitis and pancreatic cancer,and further develop CT findings,texture analysis on different phase and CT findings combined with texture analysis prediction models.Evaluate and compare the diagnostic performance of each prediction model.Methods A retrospective study collected eligible patients with mass-forming pancreatitis and pancreatic cancer who visited Jiangsu Province Hospital of Chinese Medicine and Yijishan Hospital from January 2014 to December 2017.The inclusion criteria for mass-forming pancreatitis were patients confirmed as chronic pancreatitis by surgical pathology,needle biopsy or clinical,laboratory and imaging methods.Except for confirmed by surgical pathology,all patients should be followed-up.The lesion must be smaller within three months.The inclusion criteria for pancreatic cancer was patients confirmed as pancreatic ductal adenocarcinoma by surgical pathology.The exclusion criteria were incomplete CT examination,poor image quality,and lesions less than 10 mm at the largest level of CT cross-section and patients with pancreatic cancer who received radiotherapy or chemotherapy before CT examination.Thirty patients with mass-forming pancreatitis(25 males,5 females,age range 24?78 years,mean age 61.5 years)and 79 patients with pancreatic cancer(56 males,23 females,age range 45?83 years,mean age 65.2 years)were collected.The clinical symptoms and CT imaging findings of all patients were reviewed.CT signs include the location,size,shape(round-like,lobulated or irregular),boundary(well-circumscribed or not),CT value,enhancement(homogenous or heterogenous),cystic change or calcification,pancreaticobiliary changes(penetration or truncation,dilation or not,degree of dilatation,the beaded or uniform dilation),peripancreatic vessels involvement,peripancreatic lymph nodes enlargement,peripancreatic exudation,changes of pancreatic parenchyma outside the lesion(CT value and morphology)and CT values of the psoas muscle.Texture feature parameters were obtained on non-enhanced,late-arterial and portal venous phase,including histogram,grey level co-occurrence matrix and run length matrix parameters.Lasso analysis was used for dimension reduction of abundant texture parameters to obtain the most distinguishing parameters.Two independent sample t-test or Mann-Whitney U test was used for continuous variables based on the result of Shapiro-Wilks normality test.Categorical variables were tested by chi-square or Fisher test.Multivariable logistic regression analysis was performed to develop models.The calibration of models was valuated by Hosmer-Lemeshow test and diagnostic performance by receiver operating characteristic(ROC)curve.The difference of the area under ROC(AUC)between every two models was compared by DeLong test.Results There are no significant differences in gender,age and clinical symptoms between the two groups.Mass-forming pancreatitis and pancreatic cancer mainly occurred in elderly males.The most common symptom was abdominal pain,and some patients had jaundice,nausea,weight loss,and fever.The size and CT value on late-arterial phase of the lesion and the ratio of CT value of the lesion to that of the psoas major muscle were higher in the mass-forming pancreatitis group than those in the pancreatic cancer group(4.05±1.02cm vs 3.41±1.16cm,60.57±11.24Hu vs 51.82±11.36Hu and 1.12±0.24 vs 0.96±0.21),and the CT value on late-arterial phase of the pancreas and the difference of CT value between the pancreas and the lesion were lower(73.52±13.96Hu vs 81.51±17.31Hu and 13.22±14.45Hu vs 29.12±14.49Hu).The incidence of pancreatic duct penetration sign,pancreatic duct bead-like change,pancreatic head mass with upstream pancreatic parenchymal enlargement were higher in the mass-forming pancreatitis group than that in the pancreatic cancer group(66.7%vs 19.0%,63.6%vs 17.0%and 41.7%vs 12.8%),and the incidence of peripancreatic vascular involvement,pancreatic duct dilation,pancreatic head mass with upstream pancreatic parenchymal atrophy,common bile duct truncation and double duct sign were lower(16.67%vs 53.2%,36.7%vs 59.5%,12.5%vs 36.2%,70.2%vs 20.8%and 4.2%vs 51.1%).The CT findings prediction model was developed with CT value of lesion on late-arterial phase and pancreatic duct penetration sign,of which the AUC,sensitivity,specificity,+LR and-LR were 0.841,74.7%,86.7%,5.60 and 0.29,respectively.For each phase,160 texture feature parameters were extracted from CT images.After LASSO analysis,the number of remaining parameters were 9,8 and 5 of non-enhanced,late-arterial and portal venous phase,respectively.Only 4,3 and 2 texture parameters were included in the models,respectively.DeLong test showed that the AUC of CT findings combined with texture analysis prediction model was significantly higher than that of CT findings model,texture analysis model of late-arterial and portal venous phase.There was no statistical difference of AUC between the other prediction models.The AUC,sensitivity,specificity,+LR and-LR of CT findings combined with texture analysis prediction model were 0.841,74.7%,86.7%,5.60 and 0.29,respectively.Conclusion The CT findings model and the texture analysis model have equivalent diagnostic performance in the differentiation of mass-forming pancreatitis and pancreatic cancer.The enhanced CT combined with texture analysis model has the best diagnostic efficiency and can further improve the diagnostic ability.