Localization of gastrinomas by selective intra-arterial calcium injection

Area of Science:

• Endocrinology
• Oncology
• Diagnostic Imaging

Background:

• Preoperative localization of gastrinomas is crucial for surgical success.
• Current methods like somatostatin receptor scintigraphy and secretin-stimulated testing have limitations, especially the declining availability of secretin.
• Calcium's role in neuroendocrine cell degranulation suggests its potential as a secretagogue.

Observation:

• Calcium gluconate was administered intra-arterially to two patients with proven gastrinomas under angiographic guidance.
• Gastrin levels were measured in hepatic vein samples at various time points post-injection.
• One patient had prior testing with secretin for comparison.

Findings:

• Calcium gluconate injections resulted in distinct gastrin level increases, accurately localizing gastrinomas to specific vascular territories.
• Surgical confirmation validated the tumor localizations.
• Calcium gluconate demonstrated higher specificity than secretin, as injections into non-tumor-bearing areas did not elevate gastrin levels.

Implications:

• Calcium gluconate serves as a highly sensitive and specific secretagogue for localizing pancreatic and duodenal gastrinomas.
• It offers improved accuracy in defining tumor territory compared to secretin.
• This provides a viable alternative for preoperative gastrinoma diagnosis, potentially enhancing surgical planning and outcomes.