A stent delivery system can facilitate positioning of a stent within a first vessel. The system can include an elongate member, an expandable stent coupled to the elongate member, and an imaging mechanism, such as an ultrasonic probe. The imaging mechanism can be positioned distal or proximal relative to the stent or adjacent to an aperture in the stent, such that the imaging mechanism can facilitate positioning of the stent within the first vessel such that flow into an orifice of a second vessel is not blocked by the stent.