<prompt> Which is the best investigation for metastatic gastrinoma?Selective aerial secretin injectionOctreoscanBAOMAO ratioUltrasound  <response>: In case of gastrinoma showing metastasis the diagnostic sensitivity of octreoscan is 80-100. In contrast in primary gastrinoma, Endoscopic ultrasound shows a sensitivity of 80-100 versus octreoscan which shows a sensitivity of 67-86. 