Introduction
Strain elastography (SE) allows quantifying the degree of pancreatic fibrosis in CP. Two methods of measuring pancreatic fibrosis by SE, the strain ratio (SR) and the strain histogram (SH) are available. No study has compared so far, these two methods for the diagnosis of CP.
Aims & Methods
Aim of our study was to evaluate the diagnostic yield of SR and SH for non-calcific CP.
Methods: A prospective, comparative study of the diagnostic accuracy of SR and SH for CP was designed. Patients undergoing EUS for the evaluation of CP were included. Patients with calcifying CP were excluded. Procedures were performed with linear echoendoscopes (Pentax 34J10, 38J10, and Fujifilm 740UT) and the ultrasound system Arietta 850. Rosemont EUS criteria for CP were evaluated. An area of the pancreatic body (A) was selected for SR and SH measurement. A soft extrapancreatic area was additionally selected as reference area for SR (B), being the quotient B/A the SR result. Data are shown as percentages, mean (95%CI), and analyzed by ANOVA and linear regression. The diagnostic accuracy of SR and SH were evaluated using the Rosemont classification as the reference method. STARD criteria for studies of diagnostic accuracy were followed.
Results
164 patients were included (mean age 48 years, range 17-85, 78 males). 27 (16.5%) patients presented a normal pancreas, 69 (42.1%) indeterminate findings for CP and 68 (41.5%) suggestive for CP. SR was 2.02 (1.89-2.15), 3.17 (3.02-3.32), and 4.46 (4.20-4.70), and SH 145.47 (136.25-154.69), 101.13 (96.31-105.96), and 80.04 (76.23-83.84) in normal pancreas, indeterminate and suggestive of CP, respectively (p<0.0001). Number of EUS criteria correlated significantly with the degree of pancreatic fibrosis as evaluated by SR (r=0.774, p<0.0001) and SH (r=0.770, p<0.0001). A SR > 2.45 showed sensitivity of 92.0% and specificity of 92.3% for the diagnosis of CP, with an area under the ROC curve of 0.978. Similarly, a SH <115 showed sensitivity of 87.7% and specificity of 100%, with area under the ROC curve of 0.967.
Conclusion
The quantification of pancreatic fibrosis by SR and SH during pancreatic EUS-SE show a very high and similar diagnostic accuracy in patients with suspected CP.
Disclosure
Julio Iglesia-Garcia. Advisor Pentax, FujiFil, & Mediglobe