Effectiveness of contrast-enhanced harmonic endoscopic ultrasound for the evaluation of solid pancreatic masses

AIM:To evaluate the usefulness of contrast-enhanced harmonic endoscopic ultrasound(CH-EUS)in differentiating between pancreatic adenocarcinomas and other pancreatic disease.METHODS:This retrospective cohort study evaluated90 patients who were seen between November 2010and May 2013.All these patients had solid pancreatic masses that had a hypoechoic appearance on EUS.All patients underwent CH-EUS to evaluate this diagnostic method’s usefulness.The mass lesions observed on CH-EUS were classified into three categories based on their echo intensity:hypoenhanced,isoenhanced,and hyperenhanced lesions.We adjusted the sensitivity and the specificity of each category for detecting malignancies.We also estimated the accuracy of CH-EUS by comparing it to a pathological diagnosis.RESULTS:Of the 90 patients,62 had a pancreatic adenocarcinoma.Fifty-seven out of 62 pancreatic adenocarcinomas showed a hypoenhanced pattern on CHEUS.The sensitivity was 92%,the specificity 68%and the accuracy approximately 82%.The area under the curve of the receiver operating characteristic analysis for CH-EUS was 0.799.There is a significant association between the hypoenhanced pattern on CH-EUS and pancreatic duct adenocarcinoma(χ2=35.264,P<0.001).In pathological examinations,the number of specimens for EUS-fine needle aspiration(EUS-FNA)was considered insufficient for diagnosis in three patients,and in two patients,the results were reported to be negative for malignancy.Pancreatic masses in all five patients revealed a hypoenhanced pattern with CH-EUS.Three patients were diagnosed with pancreatic adenocarcinoma based on the pathology results of a biopsy,and the remaining two patients were clinically diagnosed with malignancy.CONCLUSION:CH-EUS is useful for distinguishing between pancreatic adenocarcinoma and other pancreatic disease.When a pancreatic mass shows a hypoenhanced pattern on CH-EUS but involves either insufficient samples or negative results with EUS-FNA,clinicians might consider performing another pathologic diagnosis on the basis of an EUS-FNA sample or a biopsy.