Value of intra-arterial calcium stimulated venous sampling for regionalization of pancreatic insulinomas

Background. Intra-arterial calcium stimulation with hepatic venous sampling (ASVS) for insulin gradients has been reported to be the most sensitive pr eoperative localizing technique for insulinomas. We reviewed our experience with ASVS to localize and guide the treatment of insulinomas over the past decade. Methods. Eighteen patients who underwent ASVS before surgical exploration f or insulinoma were studied. The accuracy of ASVS was compared with intraope rative findings and other localizing studies. Results. There were no complications arising from the procedures. A more th an 2-fold step-zip in insulin level 30 to 60 seconds after injection to at least 1 feeding artery was observed in 16 patients. Fourteen of the IB soli tary tumors (87.5%) were correctly located; 100% (6/6 tumors) at the head a nd 80% (8/10 tumors) at the body/tail. The overall accuracy of this test wa s 89%, compared with 11%, 33%, 38%, and 63% of ultrasonography, computed to mography, magnetic resonance imaging, and endoscopic ultrasonography respec tively. Six enucleations and 10 distal resections were performed, which inc luded 2 laparoscopic procedures. The combination of int intraoperative ultr asonography with preoperative ASVS identified all tumors. Conclusions. ASVS is the most accurate preoperative localization tool for t he localization of insulinomas and, in combination with intraoperative ultr asonography, can enhance surgical success.