Clinical Utility of FDG PET/CT in Patients with Autoimmune Pancreatitis: a Case-Control Study

Abstract

Autoimmune pancreatitis (AIP) shares overlapping clinical features with pancreatic cancer (PC).Importantly, treatment of the two conditions is different. We investigated the clinical usefulness of 18 F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with suspected AIP before treatment. From September 2008 to July 2016, 53 patients with suspected AIP at National Taiwan University Hospital had PET/CT prior to therapy to exclude malignancy and evaluate the extent of inflammation. Their scans were compared with those from 61 PC patients. PET imaging features were analyzed using logistic regression. Significant differences in pancreatic tumor uptake morphology, maximum standardized uptake value, high-order primary tumor texture feature (i.e. high-gray level zone emphasis value), and numbers and location of extrapancreatic foci were found between AIP and PC. Using the prediction model, the area under curve of receiver-operator curve was 0.95 (P < 0.0001) with sensitivity, specificity, positive predictive, and negative predictive values of 90.6%, 84.0%, 87.9%, and 87.5% respectively, in differentiating AIP from PC. FDG PET/CT offers high sensitivity, albeit slightly lower specificity in differentiating AIP from PC. Nonetheless, additional systemic inflammatory foci detected by the whole body PET/CT help confirm diagnosis of AIP in these patients before initiating steroid therapy, especially when biopsy is inconclusive.

Radiomics analysis for the differentiation of autoimmune pancreatitis and pancreatic ductal adenocarcinoma in 18F‐FDG PET/CT

“…This study was approved by the ethics committee of Changhai hospital. 18 F-FDG PET/CT images of 45 patients with AIP and 66 patients with PDAC were retrieved from our hospital database within the period from February 2011 to November 2017. AIP patients were confirmed based on the 14th International Association of Pancreatology diagnostic criteria and 18 F-FDG PET/CT imaging results before treatment for AIP.…”

“…Detailed patient information is listed in Table I. 18 F-FDG PET/CT images were obtained by the Siemens Biograph64 PET/CT (52-ring LSO crystal and 64-slice spiral CT). 18 F-FDG (radiochemical purity >95%) was provided by Shanghai Atom Kexing Pharmaceutical Co., Ltd, Shanghai, China.…”

“…18 F-FDG PET/CT images were obtained by the Siemens Biograph64 PET/CT (52-ring LSO crystal and 64-slice spiral CT). 18 F-FDG (radiochemical purity >95%) was provided by Shanghai Atom Kexing Pharmaceutical Co., Ltd, Shanghai, China. Subjects were instructed to fast for at least 6 h, and 3.70-5.55 MBq/kg of 18 F-FDG was intravenously injected when blood glucose (BG) <11.1 mmol/ L. Then, after resting in the waiting room for 60 min, a body topogram scan was performed using an electric current of 35 mA at a voltage of 120 kV, a scan time of 10.5-15.6 s and a scan thickness of 0.6 mm.…”

“…Although features like "sausagelike" enlargement of the pancreas with a "capsule-like" rim accompanied by narrowing of the main pancreatic duct 7 are characteristic imaging findings of AIP, contrast-enhanced CT or magnetic resonance imaging does not provide specific information for AIP, especially in patients with atypical imaging features such as a focal pancreatic mass, pancreatic ductal dilatation, or distal atrophy, 5 which can be difficult to noninvasively differentiate from PDAC. 7 Compared to traditional imaging methods, 18 F-fluorodeoxglucose positron emission tomography/computed tomography ( 18 F FDG PET/CT) imaging has been reported to be particularly helpful in differentiating between AIP and PDAC, 8 especially when biopsy is inconclusive. Functional information obtained by positron emission tomography (PET) can be combined with anatomic information obtained by CT to provide a specific guide for the differentiation of AIP and PDAC.…”

“…Purpose: To perform a radiomics analysis with comparisons of multidomain features and a variety of feature selection strategies and classifiers, with the goal of evaluating the value of quantified radiomics method for noninvasively differentiating autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC) in 18 F-fluorodeoxglucose positron emission tomography/computed tomography ( 18 F FDG PET/CT) images. Methods: We extracted 251 expert-designed features from 2D and 3D PET/CT images of 111 patients, and recombined these features into five feature sets according to their modalities and dimensions.…”