Abstract: Objective The aim of this study was to observe the contrast-enhanced ultrasound (CEUS) feature and short-term efficacy of microwave ablation (MWA) in patients with liver metastatic neuroendocrine tumors(LMNET). Methods 30 patients with LMNET arose from gastrointestinal tract were admitted to the First Affiliated Hospital, Air Force Military Medical University between January 2017 and January 2022, and all underwent CEUS check-up and MWA under US guidance. Results The arrival time, time to peak and resolution time by CEUS in the 30 patients with LMNET were (17.2±3.5)s, (22.3±4.5)s and (40.9±13.1)s, and the enhancement modes included global enhancement in 24 cases (80.0%) and centripetal enhancement in 6 cases (20.0%); at peak enhancement, the lesions showed uniform, heterogeneous and circular enhancement in 18 cases (60.0%), in 8 cases (26.7%) and 4 cases (13.3%); at portal vein phase, the lesions showed mild and obvious subsides in 10 cases (33.3%) and in 20 cases (66.7%); the CEUS enhancement patterns of the lesions included fast-in and fast-out, average-in and fast-out, slow-in and fast-out in 15 cases (50.0%), in 9 cases (30.0%) and 6 cases (20.0%); after intervention of MWA, the complete remission, partial remission, stable disease and progressive disease were obtained in 21 cases(70.0%),4 cases(13.3%),3 cases (10.0%) and 2 cases (6.7%). Conclusion The most LMNET arise from the gut, and the CEUS scan showoverall and uniform enhancement, with obvious subside at portal vein phase. The short-term efficacy by MWA ispromising.

Key words: Neuroendocrine tumors, Liver metastasis, Contrast-enhanced ultrasound, Microwave ablation, Therapy