Biochemical localization of pancreatico-enteric endocrine tumours

Biochemical localization of pancreatico-enteric tumours has been proven useful, but the technique applied must be executed with great care. In this paper we present problems and some methodological demands for highly selective catheterizations within the portal system. Phlebography confirming the venous anatomy and exact position of the tip of the catheter during the bloodsampling is mandatory. Reasons for false positive and false negative investigations are discussed in order to facilitate the correct interpretation of catheterization results.