Yttrium-90 radioembolization of liver tumors: what do the images tell us?

Transarterial radioembolization (TARE) with yttrium 90 microspheres is an increasingly popular therapy for both primary and secondary liver malignancies. TARE entails delivery of beta-particle brachytherapy and embolization of the tumor vasculature. The consequent biological sequelae are distinct from those of other transarterial therapies for liver tumors, as reflected in the often baffling post-treatment imaging features. As the clinical use of TARE is increasing, more diverse post-treatment radiological findings are encountered with variable overlap among treatment response, residual disease, reactionary changes and complications. Thus, post-TARE image interpretation is challenging. This review provides a comprehensive description of the different findings seen in post-treatment scans, with the aim of facilitating appropriate radiological interpretation of post-TARE pathologic changes, notwithstanding their existing limitations.