An imaging catheter assembly comprising a catheter comprising: a proximal end; a distal end; a tubular body extending from the proximal end to the distal end; and an imaging element within the tubular body; a sheath comprising: a proximal end; a distal end; and a tubular body extending from the proximal end to the distal end, the tubular body having an inner surface, wherein the inner surface of the tubular body of the sheath at least partially defines a conduit for conveying a fluid to the distal end of the sheath, and wherein the sheath is movable such that the distal end of the sheath is positionable relative to the distal end of the catheter.