Role of Endoscopic Ultrasound in the Diagnosis of Solid Pancreatic Lesions: A Prospective Study

Abstract

Background: Endoscopic ultrasonography (EUS) provides high-resolution images of the pancreas, and it is considered one of the most accurate methods for the diagnosis and staging of solid pancreatic lesions (SPL), EUS guided fine-needle aspiration (EUS–FNA) can obtain cytological samples of pancreatic lesions, making a pathologic diagnosis possible, however, it is associated with small, but not insignificant, morbidity. The aim of this work is to determine in a prospective study, the role of EUS in the diagnosis of SPL in comparison with different radiological studies and to determine the diagnostic value of EUS guided FNA and elastography in differentiation between benign and malignant pancreatic lesions.
 Patients and methods: A total of 50 patients with SPL identified by EUS after imaging studies were enrolled in the study. The qualitative elastography score was done, also the semi quantitative score of elastography was represented by the strain ratio (SR) method where two areas were selected, area (A) representing the region of interest and area (B) representing the normal area. Area (B) was then divided by area (A). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated by comparing diagnosis made by elastography, SR with the final diagnosis (by EUS-FNA, surgery, and/or follow up for 6 months).
 Results: SPL were found to be malignant in 38 patients and benign in 12 patients. SPL was diagnosed by different imaging modalities in 39 patients with a percentage of (78%), while it was diagnosed by EUS in all 50 patients with a percentage of (100%). Elastography score alone had a sensitivity of 89.4%, a specificity of 75%, a PPV of 91.8% and an NPV of 69.2% and an accuracy of 86%. The best cut-off level of SR to obtain the maximal area under the curve was 8.42 with a sensitivity of 92.1%, specificity of 83.3%, PPV of 94.6%, NPV of 76.9% and an accuracy of 93.1%. Adding both elastography score to SR resulted in a sensitivity of 94.7%, specificity of 83.3%, PPV of 94.7%, NPV of 83.3% and accuracy of 94.3% for the diagnosis of SPL.
 Conclusion: EUS has a role in diagnosis of SPL which may be superior to different radiological studies; also, EUS-elastography and SR can be a valuable complementary supplement for EUS-FNA.