Abstract: Objective: To investigate the value of virtual monoenergetic images (VMI) in dual-energy CT (DECT) for optimizing peripancreatic vein imaging. Methods: Dual-energy CT enhanced scans (100 kV/Sn 150 kV) of 65 patients with pancreatic ductal adenocarcinoma (PDAC) and 60 healthy controls were retrospectively analyzed, and portal stage images were reconstructed at 45 keV monoenergetic and linear fusion reconstruction with a weight factor of M0.6. CT values of the pancreatic parenchyma, portal vein trunk, superior mesenteric vein, and subcutaneous fat were measured. Additionally, the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and standard deviation (SD) of the CT values of subcutaneous fat were calculated. The diameters of the superior posterior pancreaticoduodenal vein, superior anterior pancreaticoduodenal vein, and gastrocolonic trunk were measured, and the display effect of these vessels was evaluated using the five-point method. Results: The CT values, SNR, and CNR of each blood vessel and pancreatic parenchyma on 45-keV VMI were significantly higher than those on linear fusion images (PEI) (P < 0.01). The image noise of 45-keV VMI was significantly higher than that of PEI (P < 0.01). The peripancreatic venule score on 45-keV VMI was significantly higher than that on PEI (P < 0.01). In the PDAC group, excluding pancreatic tail tumors, there were 44 cases of non-resectable tumors. Twenty patients had peripancreatic small vein dilatation, accounting for 45% of non-resectable tumors; 16 patients had resectable tumors; and two patients had peripancreatic small vein dilatation, accounting for 12.5% of resectable tumors. A statistical correlation may exist between peripancreatic small vein dilatation and PDAC resectability. In the control group, three patients had peripancreatic small vein dilatation. This suggests a statistical correlation between peripancreatic small vein dilatation and PDAC positivity.