Diagnostic accuracy of endoscopic ultrasonographic shear wave elastography for assessing early chronic pancreatitis using the Japanese diagnostic criteria 2019

Abstract

Background and aim: Endoscopic ultrasound shear wave elastography (EUS-SWE) can facilitate an objective evaluation of pancreatic fibrosis. Although it is primarily applied in evaluating chronic pancreatitis, its efficacy in assessing early chronic pancreatitis (ECP) remains underinvestigated. This study evaluated the diagnostic accuracy of EUS-SWE for assessing ECP diagnosed using the Japanese diagnostic criteria 2019.

Methods: In total, 657 patients underwent EUS-SWE. Propensity score matching was used, and the participants were classified into the ECP and normal groups. ECP was diagnosed using the Japanese diagnostic criteria 2019. Pancreatic stiffness was assessed based on velocity (Vs) on EUS-SWE, and the optimal Vs cutoff value for ECP diagnosis was determined. A practical shear wave Vs value of ≥50% was considered significant.

Results: Each group included 22 patients. The ECP group had higher pancreatic stiffness than the normal group (2.31 ± 0.67 m/s vs. 1.59 ± 0.40 m/s, p < 0.001). The Vs cutoff value for the diagnostic accuracy of ECP, as determined using the receiver operating characteristic curve, was 2.24m/s, with an area under the curve of 0.82 (95% confidence interval: 0.69-0.94). A high Vs was strongly correlated with the number of EUS findings (rs = 0.626, p < 0.001). Multiple regression analysis revealed that a history of acute pancreatitis and ≥2 EUS findings were independent predictors of a high Vs.

Conclusions: There is a strong correlation between EUS-SWE findings and the Japanese diagnostic criteria 2019 for ECP. Hence, EUS-SWE can be an objective and invaluable diagnostic tool for ECP diagnosis.

Keywords: acute pancreatitis; pancreatic fibrosis; propensity score; regression analysis; shear wave elastography.

FIGURE 1

The mechanism of endoscopic ultrasound shear wave elastography (EUS‐SWE). A shear wave is generated by applying a push pulse from the probe to the target organ. The hardness of the organ is estimated by measuring the velocity of the shear wave (Vs, m/s) with a search pulse. The percentage of the net amount of effective shear wave velocity (VsN, %), which indicates the reliability of the Vs, is measured simultaneously.

FIGURE 2

Flow diagram. In total, 657 patients underwent endoscopic ultrasound (EUS). We excluded 284 patients with intrapapillary mucinous neoplasm, 45 with chronic pancreatitis, 185 with malignant disease, 56 with other diseases, and two with insufficient data on EUS‐shear wave elastography findings. Finally, 34 patients with early chronic pancreatitis and 53 without pancreatic diseases were evaluated. After propensity score matching, 22 patients from each group were included in the analysis.

FIGURE 3

Comparison of velocity (Vs) values between the early chronic pancreatitis (ECP) and normal groups. The Vs values of the ECP group were significantly higher than the normal group's (p < 0.001).

FIGURE 4

Receiver operating characteristic curves (ROCs) of the velocity (Vs) values for early chronic pancreatitis. The ROC analysis revealed that the area under the curve (AUC) was 0.82 (95% confidence interval: 0.69–0.94). The Vs cutoff value for the diagnostic accuracy of ECP was 2.24 m/s.

FIGURE 5

Correlation coefficient between velocity (Vs) values and the number of endoscopic ultrasound (EUS) findings. The Vs values and the total number of EUS findings were significantly correlated (rs = 0.626, p < 0.001).