US Patent 7758499 Method and apparatus for viewing through blood

A method, apparatus, and system for viewing through blood in situ including a flexible catheter for insertion into a blood vessel, an optical assembly positioned at the distal end of the catheter, a working channel, and a control unit for regulating the opacity level of blood in the blood vessel around the distal end of the catheter and controllably injecting quantities of fluid into the blood vessel in the vicinity of the optical assembly. A local controller located at the distal end of the catheter may control functions of the optical assembly while coordinating signals and power with the control unit. Some possible embodiments, may include an inflatable stent balloon.