Dynamic Contrast Enhanced MRI For Pancreatic Perfusion In Acute Pancreatitis

Objective: To assess the characteristics of perfusion for normal pancreas and acute pancreatitis(AP)by using dynamic contrast enhanced MRI(DCE-MRI),and to investigate the value of DCE-MRI in the grading of severity of acute pancreatitis.Methods: Twenty six patients without any pancreatic disorders(Control group)and eighty five patients with clinically proved AP were recruited in this study.All patients had performed conventional MRI sequence,multiple flip angles T1WI-LAVA and T1WI-LAVA dynamic contrast enhanced scan sequence.The Omitk DCE MRI Tool of Omni-Kinetics Version V2.0.10(GE)was used to analyze the multiple flip angles T1WI-LAVA and T1WI-LAVA dynamic contrast enhanced imaging.The Ktrans,Vp and AUC values were measured in both AP group and Control group.The perfusion parameters of the head,body and tail of normal pancreas were compared by using the Wilcoxon singned-rank test,and the perfusion parameters of AP group and Control group,the edematous pancreatitis and necrotizing pancreatitis were compared by Wilcoxon rank sum test.According to MR severity index(MRSI),the perfusion parameters in different severity grades of AP were compared by Kruskal-Wallis H test.According to the revised Atlanta classification of AP,the perfusion parameters in different severity grades of AP were compared by Kruskal-Wallis H test.Result: In the twenty six patients with normal pancreas,the Ktrans,Vp and AUC values of normal pancreas were(0.783,0.416-1.073)mL/min,(0.299,0.12-0.477),(6.793,5.486-9.397),respectively.The Vp value of normal pancreas was no statistically significant difference among the head,body and tail(all P >0.05).The Ktrans and AUC values of normal pancreas were statistically significant difference between the head and body(all P<0.05),as well as between the head and tail(all P<0.05).But no statistical difference was found between the body and tail(all P>0.05).The Ktrans,Vp and AUC values of AP were(0.511,0.274-0.74)mL/min,(0.089,0.037-0.201),(5.415,3.902-8.337)respectively,which were lower than those of control group(all P<0.05).According to MRSI,the Ktrans and AUC values were significant difference between mild and moderate AP,mild and severe AP(P<0.05),except for between the moderate and severe AP(P>0.05);there was no significant difference for pancreatic Vp value in the different severity grades of AP(P>0.05).According to the revised Atlanta classification of AP,the Ktrans value was significant difference between mild and moderately severe AP,mild and severe AP(P<0.05),except for between the moderately severe and severe AP(P>0.05);there were no significant difference for pancreatic Vp and AUC values in the different severity grades of AP(P>0.05).And the Ktrans was significant difference between the edematous pancreatitis and necrotizing pancreatitis(P<0.05),except for the Vp and AUC values(P>0.05).Conclusion: The application of DCE-MRI to evaluate pancreatic perfusion contributes to AP diagnosis and AP severity grade.Pancreatic perfusion is significantly lower in patients with AP than that in normal pancreas,and with the increase of the severity of acute pancreatitis,pancreatic perfusion tends to decrease.