Application of 18F-FDG PET/CT metabolic parameters in differentiating focal autoimmune pancreatitis from pancreatic cancer / 中华胰腺病杂志

ABSTRACT

Objective To evaluate the diagnostic value of the metabolic parameters for differentiating focal autoimmune pancreatitis (F-AIP) and pancreatic cancer (PC) by dual time 18F-FDG PET/CT scan.Methods Ten F-AIP patients and 20 PC patients in Changhai Hospital from May 2011 to November 2014 were enrolled in this study.All the AIP patients were histological confirmed or diagnosed by clinical follow up.The PC patients were histological confirmed and gender-and age-matched with F-AIP patients.50％ SUVmax was set as the threshold to fine-tune the boundary of interest.The extracted parameters included SUV SUV metabolic tumor volume (MTV),total lesion glycolysis (TLG),target-to-background ratio (TBR) and the retention indexes(RI) of all the parameters above.The PET/CT imaging features were also observed.Results The high metabolic lesions were observed in both F-AIP patients and PC patients.There were 6 F-AIP patients whose lesion was located in pancreas head,4 F-AIP patients whose lesion was located in pancreas body and tail.There were 12 PC patients whose lesion was located in pancreas head,8 PC patients whose lesion was located in pancreas body and tail.In F-AIP patients,2 cases had dilated pancreatic duct,6 had dilated biliary duct,8 had increased metabolism in mediastinal lymph node and 2 had abdominal lymphadenopathy,which were 8,5,5 and 14 cases in PC patients.The positive rate of mdeiastinal lymphadenopathy in F-AIP patients was statistically higher than that in PC patients,while the positivity rate of abdominal lymphadenopathy in AIP patients was lower than that in PC patients.The difference was statistically significant (both P ＜ 0.05).There were no statistical differences on the positivity rate of the dilated pancreatic duct,intra-and extra-hepatic bile duct between two groups.SUVmax,SUVmean and MTV in F-AIP were 5.37 ± 0.88,3.48 ± 0.66,21.79 ±15.60 in early stage and 6.45 ±1.51,4.23 ± 1.10,19.36 ± 14.63 in delayed stage,and those in PC were 8.31 ±3.08,5.41±1.95,9.26±8.35 in early stage,and 9.75±3.86,6.36±2.56,9.09±10.71 in delayed stage.SUVmax and SUVmean in F-AIP were lower than those in PC,whereas MTV were larger in F-AIP than that in PC.ROC curves for SUVmax,SUVmean and MTV were made.The AUC of SUV was the highest at 0.85,the cut-off value was 4.45,the corresponding sensitivity was 65％ and the specificity was 90％.TLG,TBR and RI of all the parameters were not statistically different in F-AIP and PC.Conclusions The 18F-FDG PET/CT metabolic parameters,such as SUVmax,SUVmean,MTV,could be of special diagnostic significance in discriminating F-AIP from PC.