Severity of hyperechoic pancreas on preoperative ultrasonography: high potential as a clinically useful predictor of a postoperative pancreatic fistula

Abstract

Purpose: This study aimed to evaluate the effectiveness of using the severity of hyperechoic pancreas (HP) observed on preoperative ultrasonography (US) as a predictor of clinically relevant postoperative pancreatic fistula (CR-POPF).

Methods: A retrospective study was conducted with 94 patients who underwent pancreatectomy between April 2006 and March 2021. The severity of HP on US was classified into two categories (normal to mild vs. moderate to severe [obvious HP]). Multiple preoperative and intraoperative parameters were analyzed to predict CR-POPF.

Results: Out of the 94 patients, CR-POPF occurred in 21 (22%) patients, and obvious HP was observed in 30 (32%). Univariate analysis revealed that moderate to severe HP (obvious HP) was significantly associated with an increased incidence of CR-POPF (P<0.001). Factors such as the absence of pancreatitis, a small main pancreatic duct (<3 mm), intraoperative soft pancreas, increased body mass index, and lower pancreatic attenuation and attenuation index were also associated with CR-POPF (all P<0.05). Multivariate analysis showed that obvious HP and soft pancreatic texture were independent predictors of CR-POPF, with odds ratios of 11.53 (P=0.001) and 14.12 (P=0.003), respectively. The combination of obvious HP and soft pancreatic texture provided the most accurate prediction for CR-POPF.

Conclusion: The severity of HP, as observed on preoperative US, was significantly associated with CR-POPF. Severe HP may serve as a clinically useful predictor of POPF, especially when evaluated alongside the intraoperative pancreatic texture.

Keywords: Fatty pancreas; Hyperechoic pancreas; Postoperative pancreatic fistula; Ultrasonography.

Fig. 1.. Flow diagram showing the patient selection criteria and study flow.

CT, computer tomography; US, ultrasonography.

Fig. 2.. Classification of hyperechoic pancreas (HP) on abdominal ultrasonography.

A. Normal pancreas shows similar echogenicity compared to the liver. B. Mild HP appears to be slightly hyperechoic compared to the liver. C. Moderate HP appears to be definitely hyperechoic compared to the liver, but hypoechoic compared to retroperitoneal fat. D. Severe HP appears to be similar or hyperechoic compared to retroperitoneal fat. P, pancreas; L, left hemiliver; R, retroperitoneal fat; SV, splenic vein.

Fig. 3.. A 79-year-old woman with ampulla of Vater (AoV) cancer who developed a clinically relevant postoperative pancreatic fistula.

A. Preoperative ultrasonography shows the pancreas (P) exhibiting hyperechogenicity similar to retroperitoneal fat (R), indicating severe hyperechoic pancreas. Borderline dilation of main pancreatic duct (arrow) and marked dilation of bile duct (CBD) are also identified. SV, splenic vein. B, C. Enhanced axial, and coronal computed tomography images confirm these findings, with a visible mass at the AoV (arrow). The patient underwent pylorus-preserving pancreaticoduodenectomy, where a soft pancreatic texture was noted intraoperatively. D. On postoperative day (POD) 4, due to elevated pancreatic enzyme levels in the percutaneous drain tube and the onset of fever, a coronal computed tomography scan was performed, revealing air-containing fluid collections (white arrows) around the pancreaticojejunostomy site (black arrow). Immediate supplemental percutaneous drainage was initiated; however, on POD 8, the patient required emergency embolization to control active bleeding from a pseudoaneurysm in the operative bed (not shown).