The emerging role of 4D flow MRI in abdominal interventional radiology.

Four-dimensional flow magnetic resonance imaging (4D Flow MRI) enables time-resolved three-dimensional visualization and retrospective quantification of vascular hemodynamics within a single volumetric acquisition. Beyond morphology-based imaging, it provides comprehensive assessment of multidirectional flow patterns, collateral redistribution, and treatment-related hemodynamic changes across vascular territories. In abdominal interventional radiology (IR), 4D Flow MRI may offer incremental value in clinical scenarios where morphology alone is insufficient to characterize physiologically relevant hemodynamics. This review summarizes its applications in aortic interventions, portal venous interventions, and hepatic venous outflow disorders. In these settings, 4D Flow MRI may support functional assessment of endoleaks, evaluation of portal flow redistribution, and characterization of venous outflow obstruction and treatment response. Among current applications, endoleak characterization and early assessment of portal hemodynamic change after portal vein embolization, which may reflect subsequent liver hypertrophy, represent particularly promising use cases. However, current evidence remains limited and largely observational. Important technical considerations, including velocity encoding strategy, physiologic variability, metal-related artifacts, and workflow integration, must be addressed. In practical terms, 4D Flow MRI is best regarded as a complementary or problem-solving technique rather than a modality for routine clinical decision-making. Further multicenter validation and outcome-driven studies are required to define its clinical impact in IR practice.