A method of transarterial embolization agent delivery at a low pressure is provided. The method comprises advancing a delivery device with an occlusion structure in a retracted non-occlusive configuration through a supply artery to a vascular position in the supply artery that is in the vicinity of a target anatomical structure, the target structure having terminal capillary beds, expanding the occlusion structure from the retracted non-occlusive configuration to an expanded occlusive configuration, lowering a mean arterial pressure in a vascular space distal to the expanded occlusion structure, redirecting fluid flow from the collateral vessels toward the lowered pressure vascular space and into the target anatomical structure, injecting an embolization agent through the delivery device and into the lowered pressure vascular space, and delivering the embolization agent from the lowered pressure vascular space into the target anatomical structure. Other catheter assemblies and methods of use are also disclosed.
