A system comprises a deployment catheter defining at least one lumen and a hood projecting distally from the deployment catheter and defining an open area. The open area is in direct fluid communication with the at least one lumen. The system also comprises an elongate channel directly coupled to the hood such that the elongate channel terminates distally into the open area. The elongate channel extends proximally from an outer surface of the hood and is bounded proximally at a proximal pocket surface. The system also comprises an imaging element. The imaging element is sized to pass into the elongated channel at a distal end of the elongate channel. Proximal movement within the elongated channel is restricted by the proximal pocket surface. The system also comprises a control member extending within the elongate channel and through the proximal pocket surface for moving the imaging element through the elongate channel.