Quantification Of The Morphohistological Features Of The Pancreas And Its Correlation With Postoperative Pancreatic Fistula

Purpose:To study the morphological and histological features of the pancreas,to quantify them by pathological and imaging study,and to analyze its correlation with postoperative pancreatic fistula.Materials and Methods:From July 2015 to February 2016,a total of 100 patients(57men,43 women;median age,59 years)underwent preoperative 1.5-T MR imaging and subsequent pancreatectomy.The width,thickness and area of the pancreatic stump,main pancreatic duct sizes,T1,T2,fat fractions,and ADC values were measured,and were compared with the fat fractions,the percentage of the exocrine gland and fibrosis degrees of specimens.The clinical,pathological and imagery parameters were compared between groups with postoperative pancreatic fistula and those without.The relationship between postoperative pancreatic fistula and the parameters was evaluated by using logistic regression analysis.Results:Pancreatic fistula developed in 73 of 100 patients while clinically relevant pancreatic fistula developed in 20,the preoperative amylase,postoperative hospital stay,transfusion,procedure,fibrosis,T1,ADC value,major complication,reoperation,readmission and death related to the hospitalization were significantly different between group with clinically relevant pancreatic fistula and group without(P<0.05).Pancreatic fraction in histology was highly positively correlated with the value measured by MR(r=0.896,P<0.01);The percentage of the exocrine gland and the grade of inflammation and fibrosis was negatively correlated(r=-0.388,P<0.01);The areas calculated by CTA and by MR was positively correlated(r=0.540,P<0.01);Univariate analysis between the morphohistological features and pancreatic fistula showed percentage of the exocrine gland more than 97.91%,fat fraction more than 1%,grade one of the inflammation and fibrosis,non-opacification of MPD in CT,MPD size measured by MRI smaller than 3mm and the area of the stump calculated by CT or MR smaller than 3.00cm~2,T1 value shorter than600ms and T2 value shorter than 54ms were all significantly correlated with postoperative pancreatic fistula.Univariate analysis also showed preoperative low amylase,non-pancreaticoduodenectomy,percentage of the exocrine gland more than 97.91%,MPD size measured by MRI smaller than 3mm and the area of the stump calculated by CT smaller than 3.00cm~2 was significantly correlated with clinically relevant pancreatic fistula.Multivariate analysis showed medial pancreatectomy or enuleation,and percentage of the exocrine gland more than 97.91%were independent risk factors for postoperative pancreatic fistula.The establishment of clinically relevant pancreatic fistula risk prediction model by logistic regression analysis showed an area of 0.802(95%CI:0.703-0.901)under the ROC curve.Conclusion:Multiparametric MR imaging of the pancreas,including a multi-echo three-dimensional gradient echo acquisition,with initial guesses for the fat and water signal fractions based on a Dixon decomposition of two selected echoes,may yield quantitative information regarding pancreatic steatosis and fibrosis,the pancreatic texture should be evaluated by the fat fraction together with the grade of the inflammation and fibrosis.High percentage of the exocrine gland and fat fraction,low grade of the inflammation and fibrosis,fine pancreatic duct and wide stump were related with postoperative pancreatic fitstula.Pancreatic fistula of grade A seemed to be more affected by the morphohistological features.Pancreaticoduodenectomy had fewer clinically relevant pancreatic fistula and the activity of pancreatic exocrine glands played a key role in this process.Further studies with more samples and randomized controlled trials are still needed.