Prospective study of the use of intraarterial secretin injection and portal venous sampling to localize duodenal gastrinomas.

BACKGROUND: Duodenal gastrinomas producing Zollinger-Ellison syndrome (ZES) are rarely imaged on preoperative studies. Measurement of serum gastrin levels by transhepatic portal venous sampling (PVS) or by sampling from hepatic veins after intraarterial secretin injection have been advocated as useful tests to identify these tumors before operation.
METHODS: As part of a prospective study, selective intraarterial secretin injection has been performed in 36 consecutive patients with ZES, PVS has been performed in 30 of these patients, and the results have been compared.
RESULTS: Gastrinomas were found at laparotomy in 33 of 36 patients (92%). Duodenal tumors were found in 18 patients (50%). The remaining patients had liver, pancreatic, or nodal disease (n = 15). Thirty-two of 36 patients (89%) had positive results with intraarterial secretin injection study, whereas 18 of 30 (60%) had a positive PVS gradient (p = 0.02, Fisher's exact test). The most common positive gradient with intraarterial secretin injection was found with injections of the gastroduodenal artery, and the most common positive gradient with PVS was found in the inferior pancreaticoduodenal (IPDV) or superior pancreaticoduodenal vein (SPDV). Fourteen of 18 (78%) patients with duodenal gastrinomas had a positive GDA injection, whereas five of 18 (28%) without duodenal tumors had a positive GDA injection (p = 0.006). Five of 16 patients with duodenal gastrinomas had a positive gradient in the IPDV or SPDV, whereas four of 14 without duodenal tumors had a positive gradient in the IPDV or SPDV (not significant).
CONCLUSIONS: Intraarterial secretin injection is more sensitive than PVS at localizing duodenal gastrinomas and should replace PVS in patients with ZES and occult tumors.