Hemodynamic Changes After Portal Vein Embolization Predict Future Liver Remnant Growth: A 4D Flow MRI Feasibility...

Early prediction of remnant liver growth after portal vein embolization (PVE) would enable earlier surgery in patients with resectable liver malignancy, decreasing the risk of tumor progression. This study aims to demonstrate the feasibility of 4D flow MRI to detect changes in portal blood flow before and after PVE and determine whether 4D flow MRI can predict hypertrophy of nonembolized liver lobes (future liver remnant) in a porcine model.

Thirteen juvenile pigs were included in this prospective study. In 11 pigs, 2 of the 4 portal vein branches were selectively embolized using polyvinyl alcohol particles. Two pigs served as controls. All animals were imaged before, 1 hour, and 1 and 2 weeks after PVE using 4D flow and T1-weighted 3D spoiled gradient-echo MRI. Flow measurements were correlated with liver volumetry measurements. The predictive value of flow changes immediately after PVE for future liver remnant hypertrophy at 2 weeks was estimated using linear mixed-effect model analysis.

Twelve pigs completed the study. One treatment pig died from complications of anesthesia. Immediately after PVE, relative flow in the 2 embolized portal vein branches decreased from 17.0±2.1% to 3.4±2.1% of total portal flow, respectively. Relative flow increased from 16.6±3.8% to 32.6±3.8% in the remaining 2 nonembolized portal vein branches supplying the future liver remnant. Each 1% increase in relative blood flow directly after the procedure predicted a 4.8±0.7 cm 3 (estimate±SE) increase in volume of the future liver remnant at 2 weeks ( P <0.0001). Conversely, in embolized lobes, each 1% flow decrease predicted a volume reduction of 3.4±1.0 cm 3 ( P =0.003).

4D flow MRI successfully quantified portal blood flow before and after portal vein embolization in a porcine model. Notably, immediate postembolization changes in portal flow were predictive of lobar volume changes observed at 2 weeks. This porcine model thus provides a valuable platform for investigating the relationship between portal hemodynamics and hypertrophy of the future liver remnant. Furthermore, it will enable systematic evaluation of various embolization agents and techniques, supporting the refinement of interventional strategies in hepatic regenerative research.