Global Hepatic Uptake of (99m)Tc-MAA During VQ Scintigraphy Secondary to Synchronous Superior and Inferior Vena Caval Obstruction: a Demonstration of Trans-Portal Venous Collateral Pathways.

Abstract

A 38-year-old woman underwent lung scintigraphy. Injection of technetium-99m macroaggregated albumin (99mTc-MAA) via the left antecubital fossa revealed global hepatic uptake (Fig. 1). Review of contemporary computed tomography (CT) imaging demonstrated synchronous superior and inferior vena cava (SVC and IVC) obstruction, with formation of systemic-portal venous collateral pathways (Fig. 2). Systemic-portal venous collateralisation can in rare circumstances lead to focal hepatic uptake of 99mTc-MAA during lung scintigraphy. This case of global hepatic uptake, secondary to synchronous SVC and IVC obstruction, demonstrates the trans-portal venous collateral pathways leading to this unusual imaging outcome (Fig. 3). Fig. 1 A 38-year-old woman, at risk of venous thromboembolic disease secondary to Factor V Leiden disorder, was referred for lung scintigraphy (a, ventilation scan posterior view). Perfusion scanning (b, left posterior oblique view) revealed global hepatic uptake ... Fig. 2 Three-dimensional CT reconstruction demonstrating left-sided systemic-portal collateral venous pathways (arrowheads retroperitoneal venous collaterals, white arrow dilated inferior mesenteric vein, black arrow haemorrhoidal plexus). Review of contemporary ... Fig. 3 Diagram of proposed systemic-portal venous collateral pathways. The first pathway involves two grossly dilated retroperitoneal veins which ascend to anastomose with a left renal/splenic venous confluence (more commonly recognised in hepatofugal flow in ...