Correlation of Technetium-99m Macroaggregated Albumin and Yttrium-90 Glass Microsphere Biodistribution in Hepatocellular Carcinoma: A Retrospective Review of Pretreatment Single Photon Emission CT and Posttreatment Positron Emission Tomography/CT

Abstract

Purpose: To evaluate whether technetium-99 (^99mTc)-labeled macroaggregated albumin (MAA) can predict subsequent yttrium-90 (⁹⁰Y) distribution and imaging response in patients with hepatocellular carcinoma (HCC).

Materials: Retrospective review was performed of records of 83 patients with HCC who underwent ⁹⁰Y glass microsphere radioembolization with ^99mTc-MAA single photon emission computed tomography (SPECT) and ⁹⁰Y positron emission tomography (PET)/CT between January 2013 and December 2014. Images were fused to segment the whole liver normal tissue (WLNT) and the largest tumors. Fused images were reviewed and analyzed for comparison of absorbed dose (AD) to tumors and WLNT as calculated from ^99mTc-MAA SPECT and from ⁹⁰Y PET/CT, subjective imaging comparison of ^99mTc-MAA SPECT and ⁹⁰Y PET for tumors and WLNT, and correlation of tumoral AD with response on follow-up CT.

Results: Final analysis included 73 and 63 patients for WLNT and tumor ^99mTc-MAA/⁹⁰Y correlation, respectively, and 62 patients for AD vs response. ^99mTc-MAA/⁹⁰Y limit of agreement for each reviewer was viewed as clinically acceptable only for WLNT (-15 to 15 Gy). AD interreviewer variability was clinically acceptable for WLNT but was too broad for tumor. Mean tumor AD for objective response (78%) was 313 Gy vs 234 Gy for nonresponders. No threshold was found between tumor AD and response (P > .1). Catheter mismatch between ^99mTc-MAA and ⁹⁰Y had a direct impact on AD mismatch between the 2 image sets.

Conclusions: ^99mTc-MAA was found to be a poor surrogate to quantitatively predict subsequent ⁹⁰Y AD to hepatocellular tumors. ^99mTc-MAA distribution correlated with ⁹⁰Y distribution in the normal hepatic parenchyma.