CaStims with multiple positive responses. A 2-fold step-up may be seen in more than one arterial injection. In case 1, a 421-fold increase in baseline insulin is seen when the SMA is injected, and a 72-fold step-up is seen on injection of the GDA. Both responses regionalize to the head. If a positive response, defined as a greater than 2-fold step-up in baseline insulin, is seen in more than one injected artery, the dominant response is taken as the site of tumor localization. Case 2 illustrates a CaStim with multiple positive responses that fails to regionalize. Positive responses are seen in ProxSplenic (4-fold), SMA (3-fold), and GDA (3-fold). Responses are seen in multiple pancreatic regions (e.g. SMA/GDA = head/neck, and ProxSplenic = body/tail), but no clearly dominant response is seen. This CaStim was performed in the work-up of a patient who was later found to be abusing repaglinide surreptitiously (41).