From the angio suite to the γ-camera: vascular mapping and 99mTc-MAA hepatic perfusion imaging before liver radioembolization--a comprehensive pictorial review

Abstract

Endovascular mapping and conjoint (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) hepatic perfusion imaging provide essential information before liver radioembolization with (90)Y-loaded microspheres in patients with primary and secondary hepatic malignancies. The aims of this integrated procedure are to determine whether there is a risk for excessive shunting of (90)Y-microspheres to the lungs; to detect extrahepatic perfusion emerging from the injected vascular territory, which might lead to nontargeted radioembolization; to reveal incomplete coverage of the liver parenchyma involved by the tumor, which may be related to anatomic or acquired variants of the arterial vasculature; and to aid in calculation of the (90)Y-microsphere dose to be delivered to the liver. This pictorial essay presents an integrated comprehensive review of the anatomic, angiographic, and nuclear imaging aspects of planned liver radioembolization. The relevant anatomy of the liver, including the standard and the variant arterial vasculature, will be shown using digital subtraction angiography, SPECT/CT, contrast-enhanced CT, and anatomic illustrations. Technical details that will optimize the imaging protocols and important imaging findings will be discussed. From the angio suite to the γ-camera-the goal of this review is to help the reader better understand how the technical details of the angiographic procedure are reflected in the imaging findings of the (99m)Tc-MAA hepatic perfusion study. In addition, the reader should learn to better recognize the pertinent findings and their clinical implications. This knowledge will enable the reader to provide a more useful interpretation of this complex multidisciplinary procedure.