1. An image registration system, comprising: an endoscope ( 12 ) operable for generating an intra-operative endoscopic image ( 14 ) of a vessel tree within an anatomical region, wherein the intra-operative endoscopic image ( 14 ) of the vessel tree includes a plurality of branches of the vessel tree visible within the intra-operative endoscopic image ( 14 ) as an indication of a furcation of the vessel tree invisible within the intra-operative endoscopic image ( 14 ); and an endoscope controller ( 22 ) operable for image registering the intra-operative operative endoscopic image ( 14 ) of the vessel tree to a pre-operative three-dimensional image ( 44 ) of the vessel tree within the anatomical region, wherein the image registration includes an image matching of a graphical representation of the furcation of the vessel tree as indicated by the visible branches of the vessel tree within the intra-operative endoscopic image ( 14 ) of the vessel tree to a graphical representation of the furcation of the vessel tree within the pre-operative three-dimensional image ( 44 ) of the vessel tree.