Yield of Contrast-Enhanced Power Doppler Endoscopic Ultrasonography and Strain Ratio Obtained by EUSElastography in the Diagnosis of Focal Pancreatic Solid Lesions

Objective: Although endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is the gold standard for diagnosingpancreatic lesions, its negative predictive value is suboptimal. Our aim was to evaluate the yield of contrast-enhanced EUS (CEDEUS)and of strain ratio EUS-elastography (SR-E-EUS) for differentiating pancreatic solid lesions.Methods: Forty-seven patients (27 men, 20 women, 70 ± 11 years) were consecutively involved in this single-center, prospectivestudy. They were submitted to EUS, SR-E-EUS, CED-EUS with Sonovue?, and EUS-FNA. The final diagnosis was based on thehistological assessment of EUS-FNA and/or surgical specimens when available, and on follow-up of at least 6 months.Results:From the 47 focal pancreatic lesions included, 13 (28%) were benign and 34 (72%) malignant. Patients with malignancywere older (70 ± 11 vs. 61 ± 8, P = 0.003), and had greater lesions (34 ± 12 mm vs. 22 ± 11 mm, P = 0.03). Malignant lesions hadhigher SR-E-EUS (31± 32 vs. 8 ± 9, P = 0.001) and more hypovascular pattern(93% vs 33%, p < 0.001 ). Logistic regression determinedthat only hypovascularity (OR = 2.6, 95%CI: 1.5-130, P = 0.02) was independently predictive of malignancy. ROC analysisfor SR-E-EUS yielded an optimal cutoff of 8 (AUC 0.91, 95%CI: 0.74-0.98) for the best power distinction for malignancy. Therewas no significant difference concerning sensitivity (79%, 90%, 93%) and specificity rates (85%, 75%, 67%) of EUS-FNA, SR-EEUS,and CED-EUS, respectively. By analysis of the inconclusive EUS-FNA subset (9 patients, 19%), SR-E-EUS > 8 and hypovascularityshowed sensitivity of 80% and 100%, and specificity of 67% and 67%, respectively.Conclusion: The clinical utility of CED-EUS and SR-E-EUS remains questionable. The accuracies of CED-EUS and SR-E-EUSare similar to EUS-FNA. Hypovascularity was independently predictive of malignancy. Patients with inconclusive EUS-FNA couldbenefit from CED-EUS due to the high sensitivity of hypovascularity for diagnosing malignancy.