Purpose <p>This study investigated the correlation between future liver remnant (FLR) hypertrophy and iodine content in the FLR following portal vein embolization, as measured by dual-energy computed tomography (DECT) with direct injection of the contrast agent into the portal vein.</p> Materials and methods <p>In this prospective study conducted at a single center, 39 patients with biliary tract carcinoma underwent right portal vein embolization prior to extended hepatectomy. After portal vein embolization, DECT was performed after injecting iodinated contrast medium into the portal vein, allowing the quantification of iodine concentration and iodine content in the FLR. Liver volumes were assessed before and after portal vein embolization to calculate the degree of hypertrophy and kinetic growth rate of the FLR. Correlations between iodine content and hypertrophy indices, such as degree of hypertrophy and kinetic growth rate, were analyzed.</p> Results <p>Post-portal vein embolization volumetric CT for FLR hypertrophy evaluation was performed at a median of 25&#xa0;days (21–30&#xa0;days). Early-phase iodine content of the left hepatic lobe on DECT was significantly correlated with both the degree of hypertrophy (DH; r = 0.380, <i>p</i> = 0.038) and the kinetic growth rate (KGR; r = 0.401, <i>p</i> = 0.028), as determined using Pearson’s correlation analysis. Likewise, late-phase iodine content of the left hepatic lobe was significantly correlated with DH (r = 0.403, <i>p</i> = 0.011) and KGR (r = 0.337, <i>p</i> = 0.036).</p> Conclusions <p>Higher iodine content in the FLR was associated with greater FLR hypertrophy after portal vein embolization. However, because the correlation observed in this study was modest, the predictive ability of this parameter could not be established. Nevertheless, DECT-based iodine quantification may provide complementary information on FLR function and warrants further investigation as a potential biomarker in future studies.</p>