Autoimmune pancreatitis (AIP) is a unique subtype of chronic pancreatitis, which shares many clinical presentations with pancreatic ductal adenocarcinoma (PDA). The misdiagnosis of AIP often leads to unnecessary pancreatic resection. 18F-FDG positron emission tomography/ computed tomography (PET/CT) could provide comprehensive information on the morphology, density, and functional metabolism of the pancreas at the same time. It has been proved to be a promising modality for noninvasive differentiation between AIP and PDA. However, there is a lack of clinical analysis of PET/CT image texture features. Difficulty still remains in differentiating AIP and PDA based on commonly used diagnostic methods. Therefore, this paper studied the differentiation of AIP and PDA based on multi-modality texture features. We utilized multiple feature extraction algorithms to extract the texture features from CT and PET images at first. Then, the Fisher criterion and sequence forward floating selection algorithm (SFFS) combined with support vector machine (SVM) was employed to select the optimal multi-modality feature subset. Finally, the SVM classifier was used to differentiate AIP from PDA. The results prove that texture analysis of lesions helps to achieve accurate differentiation of AIP and PDA.
ObjectiveTo analyze the R0 resection rate and survival time of pancreatic cancer with serum IgG4 elevated, and to discuss whether serum IgG4 can distinguish autoimmune pancreatitis from pancreatic cancer.MethodsThe retrospective cohort study was adopted. The clinical data of 146 patients with pancreatic cancer confirmed by histology in Affiliated Hospital of Qingdao University from January 2016 to December 2019 were analyzed retrospectively. According to the level of serum IgG4, they were divided into normal IgG4 group (<1.35 g/L, n=124) and IgG4 elevated group (≥1.35 g/L, n=22). The tumor R0 resection rate, survival time and whether complicated with AIP of the two groups were compared.ResultsOne hundred and one patients (81.5%) with normal serum IgG4 underwent radical surgery, while only 13 patients (59.1%) with elevated serum IgG4 underwent radical surgery, the difference was significant (P=0.019). The median survival time of patients with normal serum IgG4 was 18.7 months, while patients with elevated serum IgG4 was 8.1 months, there was no significant difference between the two groups (P=0.121). Subgroup analysis showed that the median survival time of patients with pancreatic ductal adenocarcinoma in the normal IgG4 group was 17.5 months, while the IgG4 elevated group was 6.8 months, the difference was significant (P=0.016). Only 1 case of pancreatic cancer with AIP in the 2 groups.ConclusionsSerum IgG4 ≥1.35 g/L indicates low radical resection rate in pancreatic cancer and poor prognosis in pancreatic ductal adenocarcinoma. Serum IgG4 can only be used as an auxiliary index to distinguish pancreatic cancer from autoimmune pancreatitis.