Evaluation of the performance of and interobserver agreement on postoperative baseline CT findings in the identification of locoregional recurrence in patients with pancreatic ductal adenocarcinoma.

Purpose: To evaluate interobserver agreement on the findings of baseline contrast-enhanced multidetector computed tomography (CE-MDCT) performed at the postoperative third month in patients who underwent surgery due to ductal adenocarcinoma of the pancreatic head and investigate the value of these findings in predicting locoregional recurrence.

Material And Methods: The baseline CE-MDCT images of 198 patients who underwent the Whipple procedure due to pancreatic head tumors were evaluated independently by three radiologists at the postoperative third month. The radiologists were asked to note suspicious findings in terms of locoregional recurrence, including postoperative fat stranding, the presence of perivascular contrast-enhanced solid tissue, short diameter of solid tissue if present, the shape of solid tissue (convex/concave), presence of peritoneal implants, diameter (mm) of pancreatic duct dilatation if present, the presence of lymph nodes larger than 5 mm, portal vein stenosis (≥50 and <50%), the presence of ascites, and the presence of distant metastases, as specified by the Society of Abdominal Radiology in October 2022. The agreement between the radiologists and the value of these parameters in predicting locoregional recurrence were investigated.

Results: Among the CE-MDCT findings evaluated, the radiologists had a moderate-to-high level of agreement concerning the presence of perivascular contrast-enhanced solid tissue. However, there was a poor interobserver agreement on the shape of solid tissue. A very high level of agreement was found among the radiologists in the evaluation of pancreatic duct dilatation, peritoneal implants, ascites, and the presence of distant metastases. According to the univariate analysis, the rates of portal vein stenosis had a 1.419 -fold effect [odds ratio (OR)=1.419, [95% confidence interval (CI)= 0.548-3.679, p=0.041], lymph node presence had a 2.337 -fold effect [odds ratio (OR)=2.337, [95% confidence interval (CI)= 1.165-4.686, p=0.015], perivascular contrast-enhanced solid tissue had 2.241 -fold effect [odds ratio (OR)=2.241, [95% confidence interval (CI)= 1.072-4.684, p=0.005]. In the multivariate analysis, perivascular contrast-enhanced solid tissue had 2.241 -fold effect [odds ratio (OR)=2.519, [95% confidence interval (CI)= 1.132-5.605, p=0.024].

Conclusion: In the postoperative baseline CE-MDCT examination, the presence of solid tissue, lymph node presence, and portal vein stenosis in the surgical bed are among the findings that may indicate early locoregional recurrence in patients with pancreatic ductal adenocarcinoma.