An apparatus includes an instrument that comprises an elongated, flexible body including an inner surface and an outer surface, wherein the inner surface is shaped to define a lumen extending through at least a portion of the elongated, flexible body. The instrument further comprises a plurality of portions extending along a length of the elongated, flexible body. The apparatus further comprises a radiopaque material incorporated into a first portion of the plurality of portions and a second portion of the plurality of portions, wherein the radiopaque material is incorporated into the first portion such that the first portion has a first radiopacity, and the radiopaque material is incorporated into the second portion such that the second portion has a second radiopacity, wherein the first radiopacity is different from the second radiopacity.