Segmental perfusion differences (SPD) on paired Tc-99m MAA hepatic perfusion imaging (HPI) and Yttrium-90 microsphere (Y-90) imaging: Associations with angiography

88 Objectives Tracer perfusion on paired HPI and Y-90 studies does not always match, which may cause inaccuracy in tumor dosimetry. The cause is mostly unknown. This study identified angiographic related factors associated with SPD. Methods 81 paired HPI and Y-90 SPECT-CT images and corresponding angiographies were reviewed. SPD were defined as differences in perfused areas that involve liver segment on SPECT-CT. The infusion site, including right (RHA), left (LHA) or proper hepatic arteries (PHA); catheter tip position (different if distance >5mm); presence of arterial bifurcation or branch near catheter tip (positive if distance to tip Results 31 studies showed SPD. SPD were less frequently observed with infusion into LHA as compared to PHA and RHA (P Conclusions SPD is associated with angiographic related factors including differences in catheter tip position, arterial bifurcation or branch near catheter tip. Combination of these factors is strongly associated with SPD than each factor alone