Methods of modifying the luminal profile of a body vessel are described. An example method comprises advancing a cannula out of the distal end of a catheter disposed within the lumen of a body vessel of an animal and toward a target site on the wall of the body vessel; passing contrast dye through the cannula toward the target site; simultaneously continuing the advancing and passing until the distal end of the cannula punctures the inner layer of the wall of the body vessel at the target site; and passing a bulking agent through the cannula and into a space between connective tissue layers surrounding the vessel wall at the target site. Medical devices, medical device assemblies, and kits are also described.