Do preoperative pancreatic computed tomography attenuation index and enhancement ratio predict pancreatic fistula after pancreaticoduodenectomy?

BACKGROUND: The commonly used predictors of clinically relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD) have subjective assessment components and can be used only in the postoperative setting. Also, the available objective predictors based on preoperative cross-sectional imaging were not prospectively studied. AIM: To evaluate the accuracy of the pancreatic attenuation index (PAI) and pancreatic enhancement ratio (PER) for predicting CR-POPF following PD and its correlation with pancreatic fat fraction and fibrosis. METHODS: A prospective observational study included patients who underwent PD for benign and malignant pathology of the periampullary region or pancreatic head between February 2019 and February 2021. Patients undergoing extended or total pancreatectomy and those with severe atrophy of pancreatic tissue or extensive parenchymal calcifications in the pancreatic head and neck precluding calculation of PAI and PER were excluded from the study. Preoperatively PAI was measured in the neck of the pancreas by marking regions of interest (ROI) in the non-contrast computed tomography (CT), and PER was measured during the contrast phase of the CT abdomen. Also, the fibrosis score and fat fraction of the pancreatic neck were assessed during the histopathological examination. Demographic, clinical and preoperative radiological indices (PAI, PER) were evaluated to predict CR-POPF. Preoperative pancreatic neck CT indices were correlated with the histopathological assessment of fat fraction and fibrosis. RESULTS: Of the 70 patients who underwent PD, 61 patients fulfilling the inclusion criteria were included in the analysis. The incidence of CR-POPF was 29.5% (18/61). PAI had no association with the development of CR-POPF. Of the preoperative parameters, PER (mean ± standard deviation [SD]) was significantly lower in patients developing CR-POPF (0.58 ± 0.20 vs 0.81 ± 0.44, P = 0.006). The area under the curve for the PER was 0.661 (95%CI: 0.517-0.804), which was significant (P = 0.049). PER cut-off of 0.673 predicts CR-POPF with 77.8% sensitivity and 55.8% specificity. PAI and PER had a weak negative correlation (Strength-0.26, P = 0.037). Also, PER showed a moderately positive correlation with fibrosis (Strength 0.50, P < 0.001). Patients with CR-POPF had a significantly higher incidence of the intraabdominal abscess (50% vs 2.3%, P < 0.001), delayed gastric emptying (83.3% vs 30.2, P < 0.001), and prolonged mean (± SD) postoperative hospital stay (26.8 ± 13.9 vs 9.6 ± 3.6, P = 0.001). CONCLUSION: PER exhibited good accuracy in predicting the development of CR-POPF. PER additionally showed a good correlation with PAI and fibrosis scores and may be used as an objective preoperative surrogate for assessing pancreatic texture. However, ROI-based PAI did not show any association with CR-POPF and pancreatic fat fraction.