Embodiments of an injector, injector system, syringe, syringe interface, syringe adapter, and piston/plunger assembly for an injector (of contrast medium, for example) are described. Preferably, the syringe is adapted to engage a syringe interface mechanism such that the syringe may be seated within an injector without regard to any particular orientation of the syringe about its axis with respect to the injector.