Abdominal ultrasound may be helpful in the diagnosis of Zollinger-Ellison syndrome caused by gastrinoma.^[1]. Ultrasonography can detect gastrinomas in 30%. Endoscopic ultrasonography (EUS) is a highly sensitive and specific procedure for the localization of pancreatic endocrine tumors and duodenal as well as pancreatic gastrinomas.

• In 30% of cases Ultrasonography can detect gastrinomas and the detection rates are better for lesions greater than 3 cm in diameter and are poor for lesions smaller than 1 cm. ^[2]
• Endoscopic ultrasonography (EUS) is a highly sensitive and specific procedure for the localization of pancreatic neuroendocrine tumors and should be considered for the preoperative localization of such tumors once the clinical and laboratory diagnosis has been established. ^[3]
• Endoscopy or EUS should also be performed when a gastrinoma is suspected in order to identify duodenal as well as pancreatic gastrinomas, especially when multiple lesions are suspected as in MEN 1. ^{[4] [5]}