Abstract No. 530 - Hepatic vein imaging findings associated with elevated lung shunt fraction in patients being considered for yttrium-90 radioembolization

Abstract

No. 530 Hepatic vein imaging findings associated with elevated lung shunt fraction in patients being considered for yttrium-90 radioembolization O.G. Olorunsola, N. Fidelman, S. Behr, M. Kohi, K. Kolli, A.G. Taylor, R. Tong, J. LaBerge, R.K. Kerlan, Jr.; Radiology, University of California, San Francisco, San Francisco, CA Purpose: To identify hepatic vein (HV) morphologic and flow abnormalities associated with elevated lung shunt fraction (LSF) determined by Technetium-99m (Tc) macroaggregated albumin (MAA) imaging in patients being considered for yttrium-90 (Y) radioembolization. Materials and Methods: This single-center retrospective study included 152 consecutive patients who underwent mapping arteriography with Tc-MAA injection from 2009 to 2014 (50 with hepatocellular carcinoma [HCC], 102 with other tumors; 103 men, 49 women; median age 62). Each preprocedure imaging examination (CT or MRI) was assessed for HV tumor thrombus or HV occlusion from external compression by tumor. In addition, two readers separately evaluated the mapping arteriograms and the arterial phase from multiphase CTs (117 patients) for evidence of early HV opacification (relative to unaffected HVs), with consensus determined by a third reader. These factors were correlated with LSF categories (low [o10%], intermediate [10-20%], and high [420%]) determined by Tc-MAA imaging using uniand multivariate analysis. Results: Median LSF was 6.7% (range 0-71%; 74.3% low, 18.4% intermediate, 7.2% high). There was high interobserver agreement for determining early HV opacification (97%, kappa1⁄40.847). Early HV opacification at CT and angiography each were associated with higher LSF category (po.001 for both modalities). This finding at CT was 78% sensitive and 93% specific for predicting high (420%) LSF (64% sensitive and 95% specific at angiography). Of five cases of HV tumor thrombus (3 HCC, 2 other tumors), all had high (420%) LSF (po.001). HV occlusion due to external tumor compression was also associated with higher LSF category (p1⁄4.04). Multivariate analysis confirmed that early HV opacification at CT and either HV tumor thrombus or occlusion were associated with higher LSF category. Conclusion: Early HV opacification and HV tumor thrombus or occlusion on pre-procedure cross-sectional imaging are associated with elevated LSF, which may contraindicate or limit the dose delivered in Y radioembolization. This information could be helpful during patient counseling for anticipating the most appropriate mode of liver-directed therapy.