US Patent 7635345 Pressure-propelled system for body lumen

Apparatus is provide for use with a fluid pressure source, including an elongate carrier, adapted to be inserted through a proximal opening of a body lumen, and a distal piston head coupled to a distal portion of the carrier. The piston head is adapted to be in direct contact with a wall of the lumen when the carrier is inserted into the lumen, and to be advanced distally through the body lumen in response to pressure from the fluid pressure source. Additionally, the piston head is typically adapted to facilitate passage of fluid out of the lumen from a site within the lumen distal to the piston head.