Strain ratio vs strain histogram for the elastographic evaluation of non-calcific chronic pancreatitis (CP): a prospective, single-centre, comparative study

 

Aims Diagnosis of CP at early stages is a challenge due to the limited accuracy of the available diagnostic methods. Endoscopic ultrasound (EUS) guided strain elastography (SE) allows the evaluation of pancreatic fibrosis in this setting. Our study aimed to evaluate the diagnostic yield of the two quantification methods of SE, strain ratio (SR) and strain histogram (SH), for the diagnosis of non-calcific CP.

Methods Prospective, cross-sectional, single-centre, comparative study of diagnostic accuracy. Patients undergoing EUS-guided SE for the evaluation of non-calcific CP were included. Procedures were performed with linear echoendoscopes (Pentax 34J10 and 38J10, and Fujifilm 740UT) attached to the ultrasound system Arietta 850. The number of EUS criteria for CP was evaluated according to the Rosemont classification. An area of the pancreatic body was selected for the evaluation of SH. The same body area (area A) and a soft extrapancreatic area (area B) were selected for SR. Data are shown as percentages and mean (95% CI), and analyzed using ANOVA and linear regression. The diagnostic accuracy of SR and SH was evaluated using the Rosemont classification as the reference method. STARD criteria for studies of diagnostic accuracy were followed.

Results 269 patients were included (mean age 49.5 years, range 17-85, 137 males). 41 patients (15.2%) presented a normal pancreas, 106 (39.4%) indeterminate findings for CP and 122 (45.4%) suggestive findings for CP. SR was 2.05 (1.94-2.15), 3.02 (2.90-3.13), and 4.39 (4.22-4.56), and SH 144.95 (137.92-151.98), 104.01 (100.56-107.46), and 80.56 (77.89-83.23) in normal pancreas, indeterminate and suggestive of CP, respectively (p<0.0001). SR>2.42 showed a sensitivity of 92.1% and a specificity of 87.5% for the diagnosis of CP (ROC curve 0.968). SH<116.1 showed a sensitivity of 88.2% and a specificity of 97.5% for the diagnosis of CP (ROC curve 0.970). The number of EUS criteria correlated with the degree of pancreatic fibrosis as evaluated by SR (r=0.754, p<0.0001) and SH (r=0.782, p<0.0001).

Conclusions The quantification of the degree of pancreatic fibrosis by SR and SH during pancreatic EUS-guided SE shows a high and similar diagnostic accuracy in patients with suspected CP.

Publication History

Article published online:
15 April 2024

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