Quantification of Pancreatic Stiffness on Intraoperative Ultrasound Elastography and Evaluation of its Relationship With Postoperative Pancreatic Fistula

Abstract

"Soft pancreas" has often been reported as a predictive factor for postoperative pancreatic fistula (POPF) after pancreatectomy. However, pancreatic stiffness is judged subjectively by surgeons, without objective criteria. In the present study, pancreatic stiffness was quantified using intraoperative ultrasound elastography, and its relevance to POPF and histopathology was investigated. Forty-one patients (pancreatoduodenectomy, 30; distal pancreatectomy, 11) who underwent intraoperative elastography during pancreatectomy were included. The elastic ratio was determined at the pancreatic resection site (just above the portal vein) and at the remnant pancreas (head or tail). Correlations between the incidence of POPF and patient characteristics, operative variables, and the elastic ratio were examined. In addition, the relationship between the elastic ratio and the percentage of the exocrine gland at the resection stump was investigated. For pancreatoduodenectomy patients, main pancreatic duct diameter < 3.2 mm and elastic ratio < 2.09 were significant risk factors for POPF. In addition, the elastic ratio, but not main pancreatic duct diameter, was significantly associated with the percentage of exocrine gland area at the pancreatic resection stump. Pancreatic stiffness can be quantified using intraoperative elastography. Elastography can be used to diagnose "soft pancreas" and may thus be useful in predicting the occurrence of POPF.

Usefulness of endoscopic ultrasonography‐elastography as a predictive tool for the occurrence of pancreatic fistula after pancreatoduodenectomy

“…In fact, in the current study the measurement of elasticity via EUS-EG was successful in almost all patients (n = 60/61, 98%). In another study, intraoperative ultrasonography elastography (IOUS-EG) was used to evaluate the softness of the pancreas [36]. However, the AUROC of IOUS-EG for predicting PF was 0.739, which is inferior to that of EUS-EG observed in the current study.…”

Systematic review and meta-analysis of postoperative pancreatic fistula rates using the updated 2016 International Study Group Pancreatic Fistula definition in patients undergoing pancreatic resection with soft and hard pancreatic texture

“…Finally, 122 studies were included. Of those 122 studies, 110 studies 3, [13][14][15][17][18][19][20][21][22][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127] were included in both qualitative synthesis and meta-analysis and 12 16,[128][129][130][131][132][133][134][135][136][137][138] only in the qualitative synthesis (eTable 2).…”

The EFSUMB Guidelines and Recommendations for the Clinical Practice of Elastography in Non-Hepatic Applications: Update 2018

“…In patients with chronic pancreatitis, pancreatic shear wave velocities [116,124,127,131,186], SR [148] and SH [146] are significantly higher than in healthy volunteers or patients with a normal pancreatic parenchyma. Several studies have shown a significant correlation between SWE [117,123,184] and semi-quantitative SE [138,167,169,185] and histological pancreatic fibrosis stage. Moreover, SWE [122,124,169] and SR [141] are significantly correlated with stages of chronic pancreatitis derived from EUS-based criteria for the diagnosis of chronic pancreatitis.…”

“…Evaluation of pancreatic stiffness might be an objective index to estimate pancreatic fibrosis and predict the risk of postoperative pancreatic fistula. Data from several studies suggest that SWE [115,117,184,188] and SE [138,170,185] may be used for this purpose. In particular, a pancreatic parenchyma with a low stiffness as determined by semi-quantitative SE [138,170] or SWE [117] proved to be an independent predictor of postoperative pancreatic fistula.…”

“…Disadvantages for ultrasound elas-tography include organ deformity intraoperatively due to a number of factors including tumor resection sequelae and post-interventional swelling. The use of intraoperative elastography has been reported for the liver [8, 9, 432 -435], brain [436 -443], pancreas [115,185], prostate [444], lung [445] and other organs [446].…”