Sa1473 CONTRAST-ENHANCEMENT ENDOSCOPIC ULTRASOUND FOR PANCREATIC NEUROENDOCRINE TUMORS: EXPERIENCE FROM ONE SINGLE INSTITOTION OF TAIWAN

Abstract

Neuroendocrine tumors of the pancreas (pNET) are less common than pancreatic ductal adenocarcinoma. Endoscopic ultrasound (EUS) is recommended as the method of choice for detection of very small pancreatic tumors. Contrast-enhanced endoscopic ultrasound (CE-EUS) is helpful in characterizing pancreatic tumors which are incidentally found on other imaging. However, little known about how pNET in different grades present on CE-EUS. In our study, we used an ultrasound contrast agent (Sonazoid®) with microbubbles and investigated the characteristics of diagnosed pNET (particularly at an early stage) through CE-EUS by imaging the uptake of the microbubbles by the macrophages. The objective of this study was to examine the characteristics of pNET in different grades on CE-EUS. We retrospectively analyzed the characteristics of CE-EUS of pNETs confirmed by EUS-FNA or surgical pathology at our hospital between Dec. of 2018 to July of 2019. Using an EUS device compatible with operations in the contrast harmonic mode, after B-mode observations, we intravenously administered 7.5 μl/kg of Sonazoid® and conducted longitudinal observations from an early stage, which included up to 180 seconds in the contrast mode. We investigated the changes in the pancreatic tumorous findings before the contrast enhancement and in the early and later phases. Among 5 patients with histologically proved pNETs during the study period, one patient had 3-cm pancreatic mass with pathological diagnosis with combination of adenocarcinoma and NET which CE-EUS demonstrated persistent hypo-enhancement with heterogeneous echogenicity of the parenchyma which was similar finding as the adenocarcinoma of pancreatic cancer. One patient had diagnosed as 2.5-cm grade 2 pNET with hyper- and hypo-enhanced lesion and somewhat heterogeneous echotexture under CE-EUS. Another 3 patients with size from 0.5 to 4cm with diagnosed as grade 1 low grade pNET had the imageing of CE-EUS mostly with hyper-enhancement at early stage and hypo-enhancement at delayed phase with homogeneous echogenicity. The CE-EUS findings between different differentaion of pNET became distinct, thus suggesting that CE-EUS may be helpful for evaluation and estimation of the prognosis for pNET.Grade 2 pNET: hyper and hypoenhanced and somewhat heterogeneous echotexture (arrow)View Large Image Figure ViewerDownload Hi-res image Download (PPT)