Usefulness of contrast-enhanced endoscopic sonography for discriminating mural nodules from mucous clots in intraductal papillary mucinous neoplasms: a single-center prospective study.

OBJECTIVES: The aim of this study was to evaluate the ability of contrast-enhanced endoscopic sonography for discrimination of mural nodules from mucous clots in intraductal papillary mucinous neoplasms of the pancreas. METHODS: Contrast-enhanced endoscopic sonography was performed in 17 consecutive patients who had an intraductal papillary mucinous neoplasm with mural lesions. To perform contrast-enhanced endoscopic sonography, we used a second-generation sonographic contrast agent. After reconstitution with 2 mL of sterile water for injection, 0.7 mL of the agent was administered through a peripheral vein. From 10 to 30 seconds after injection of the contrast agent, the presence or absence of vascularity in mural lesions was assessed. All cases were referred to surgery, and diagnoses were finally obtained by pathologic examination. Diagnoses of mural nodules versus mucous clots based on the sonographic results were compared with tumor histopathologic findings. RESULTS: Pathologic findings revealed 12 cases with mural nodules and 5 cases without. Contrast-enhanced endoscopic sonography depicted vascularity in all 12 cases with pathologically confirmed mural nodules, whereas all 4 cases without vascularity had mucous clots. Only 1 case without a pathologically confirmed mural nodule was overestimated by contrast-enhanced endoscopic sonography as having a mural nodule. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of contrast-enhanced endoscopic sonography for mural nodule detection were 100%, 80%, 92%, 100%, and 94%, respectively. CONCLUSIONS: Evaluation of vascularity by contrast-enhanced endoscopic sonography could be useful for distinguishing mural nodules from mucous clots in intraductal papillary mucinous neoplasms. Contrast-enhanced endoscopic sonography could be a necessary option to determine surgical indications for intraductal papillary mucinous neoplasms when mural lesions are observed.