Objective To explore the value of enhanced MRI for differentiating hypovascular pancreatic neuroendocrine tumors from pancreatic ductal adenocarcinoma.

Methods From January 2015 to December 2020, the clinical data of 39 patients with pancreatic neuroendocrine tumors confirmed by pathology and 37 patients with pancreatic cancer confirmed by operation pathology or biopsy pathology from January 2020 to December 2020 in Zhongshan Hospital, Fudan University were retrospectively analyzed. Multivariate regression analysis was used to analyze the imaging features affecting the differential diagnosis, and the ROC curve was drawn according to the clinical and imaging features.

Results Compared with pancreatic ductal adenocarcinoma, patients with hypovascular pancreatic neuroendocrine tumors have a younger age of onset (years vs years, P < 0.001), clearer borders (81.1% vs 43.6%, P=0.001), and lower main pancreatic duct dilatation rate (23.1% vs 70.3%, P < 0.001), lymph node metastasis (25.6% vs 48.6%, P=0.038) and peripheral fat infiltration is less common (43.4% vs 89.2%, P < 0.001), the three-stage enhancement rate after enhancement is higher than the pancreatic cancer group (all P < 0.001). Among the imaging features, the main pancreatic duct dilatation, peripheral fat infiltration, and enhancement mode were independent predictors of differential diagnosis. Combined with multi-factor ROC curve analysis, the measured area under the curve is 0.93, the diagnostic sensitivity is 91.7%, and the specificity is 83.3%.

Conclusions The clinical symptoms, tumor boundary, contrast enhancement rate, and metastasis are considered to be the typical imaging findings of hypovascular pancreatic neuroendocrine tumors.