A patient with liver metastases and on angiotensin-converting enzyme inhibition for hypertension was studied after administration of Tc-99m MAA through the hepatic artery. The scintigrams showed a highly selective perfusion of the metastases (and significant shunting) despite the systemic treatment with a vasoactive drug that, theoretically, diminishes the flow to metastases. A possible effect of concomitant vasoactive medication on targeting and systemic side effects should be considered if regional perfusion studies and intra-arterial treatment are performed.