Interventional Embolization Under Multifactorial Coupling: Mechanisms of Embolic-Agent Distribution and Feasibility of Closed-Loop Automatic Injection.

PURPOSE: This narrative review aims to synthesize current knowledge on the mechanisms governing embolic-agent distribution and to examine the engineering rationale and translational feasibility of closed-loop or semi-automated embolic-agent injection. METHODS: A structured search and targeted review of experimental, computational, and clinical studies were used to synthesize evidence on particle properties, injection parameters, hemodynamics, imaging feedback, and pressure monitoring related to embolization. Evidence was analyzed from a biomedical engineering perspective, with emphasis on transport mechanisms, sensing modalities, and control-relevant variables. RESULTS: Embolic-agent distribution arises from the coupled effects of particle size, shape, and material properties; injection rate, mode, and catheter configuration; and lesion- and device-induced hemodynamic alterations. Quantitative digital subtraction angiography (qDSA and 4D-DSA) provides spatial and perfusion-related information, whereas local arterial pressure more directly reflects distal resistance evolution and reflux tendency. Taken together, these findings support an engineering interpretation of embolization as a constrained transport-flow-control process in which embolic distribution, endpoint assessment, and procedural safety are jointly influenced by particle characteristics, hemodynamics, and feedback-informed injection strategy. CONCLUSION: By reframing embolization as a coupled transport and control problem, this review integrates multifactorial distribution mechanisms with multimodal feedback concepts and outlines a preliminary engineering framework for future feedback-informed embolic-agent delivery systems.