• arterial and perineural involvement
• CT staging
• pancreatic ductal adenocarcinoma

CT evaluation of arterial and perineural involvement in patients with advanced pancreatic ductal adenocarcinoma:
In the modern era of multimodal treatment of pancreatic cancer, detailed and standardized radiological definition of local tumor spread is of paramount importance to select patients with LA pancreatic adenocarcinoma suitable for surgery. Our data reinforce the concept that we have no actual proof that surgery is not beneficial in patients with suspected arterial involvement, and prompts further investigation to elucidate the prognostic implication of radiological T4 diagnosis in pancreatic cancer. On the basis of our CT grading of vascular involvement, circumferential encasement (grade IIa and IIb) and reduction of caliber (grade IIIa and IIIb) showed a PPV of infiltration of 52.9% and 82.2% for veins and 33.3% and 32.1% for arteries respectively.The strong tropism of ductal carcinoma for perineural spreading along arterial structures, justifies the need to use different criteria for grading venous and arterial infiltration in preoperative CT local staging; current CT grading system, originally developed for veins, should therefore be revised because of the many anatomic and structural differences between arteries and veins and the different relationships of these vessels with extrapancreatic nerve plexus.