An excisional device may comprise an introducer comprising a distal trough portion and a cutting assembly. The cutting assembly may comprise an axial band element configured to selectively bow out of and away from the distal trough portion and to retract into the distal trough portion and a helical cutting element wound around the axial band element. A rotating drum may be provided to cause the cutting assembly to selectively rotate, bow and retract according to a mechanically-driven first cutting profile that is defined by a shape of a channel formed in the drum. An optical guidance projector assembly may be coupled to the excisional device and may be configured to visually indicate when a distal portion of the excisional device is aligned with an imaging plane of an imaging probe and in a desired position.
