[Computed tomography in determining the differentiation of ductal adenocarcinoma of pancreatic head]

To evaluate the features of «hypervascular rim», tumor dimensions and density as prognostic factors of differentiation of pancreatic head adenocarcinoma.

Pancreatoduodenectomy was performed in 311 patients with pancreatic head adenocarcinoma for the period 2013-2019. A retrospective study included 81 patients who met the following criteria: available data of morphological and immunohistological examination indicating tumor grade from Grade 1 to Grade 3, as well as available preoperative CT images in four phases (native, arterial, portal and delayed). Tumor dimensions, density of the pancreas, adenocarcinoma and abdominal aorta by the phases of contrast enhancement were analyzed in all patients. Moreover, we estimated coefficient of relative enhancement change. Perifocal hypervascular enhancement was assessed in arterial and portal phases. Contrast-enhanced MRI was performed in 15 out of 81 patients. MR images were analyzed regarding a hypervascular rim, and the last one was compared with CT images.

There was no significant difference in density values between different tumor grades. Coefficient of relative enhancement change >1 was observed in 63.64% of highly-differentiated tumors. REC ≤1 was found in 85.11% of tumors grade 2 and 82.6% of tumors grade 3 (p=0.005). According to Chi-square test, there was a correlation between tumor differentiation and hypervascular rim (p=0.03). Moderate and low differentiation was observed in 96.42% of tumors with perifocal enhancement. Hypervascular rim was absent in 81.82% of tumors grade 1. Adenocarcinoma grade 2 was found in 85.71% of cases with unclear perifocal enhancement.

Preoperative contrast-enhanced CT is valuable to assume the tumor grade in patients with pancreatic head adenocarcinoma due to assessment of hypervascular rim and REC.