A tissue manipulation system comprises a reconfigurable hood structure. The hood structure is asymmetric and has a low profile delivery configuration and an expanded deployed configuration which defines an open area bounded at least in part by the hood structure and by an interface surface extending across the hood structure distal end and configured to engage against a tissue region. The open area is in fluid communication with an environment external to the hood structure. The system also includes a catheter in communication with the open area such that introduction of a fluid through the catheter purges the open area of bodily fluid. The interface surface is slanted relative to the catheter longitudinal axis when the hood structure is fully expanded in the expanded deployed configuration. The system also includes an imaging element positioned on the hood structure such that the open area is visualized through the fluid.