POMC and gastrin-producing neuroendocrine tumor: While the SACI test is well established for insulinomas and gastrinomas, where increases of over 3-fold and 1.2-fold from baseline, respectively, are considered diagnostic, no standardized cutoff exists for ACTH-producing tumors.16,17) In this patient, the ACTH response to arterial stimulation was modest (1.2–1.4-fold), but baseline RHV levels were higher than IVC and LHV levels, suggesting right hepatic lobe predominance.