Digital image processing method for automatic detection of stenoses

Claim 1

A digital angiography method comprising acquiring a digital angiographic image representing vessels on a background, and automatically performing the following steps in an image processing system: identifying pixels of the digital angiographic image situated on median lines of vessels, referred to as median pixels; examining intensity values at the identified median pixels; identifying vessel segments corresponding to median pixels exhibiting a local variation of intensity with respect to median pixels situated upstream and downstream on the same median line, as potential stenosis zones; subsequent to said identifying potential stenosis zones, extracting pixels at edges of the vessel segments only in said potential stenosis zones; identifying strictures in said vessel segments in said potential stenosis zones based on the locations of extracted pixels at edges of the vessel segment; determining for each potential stenosis zone, upon characteristics including the intensity of median pixels and distance between edges of the vessel segment in said potential stenosis zone at an identified stricture, whether or not the identified stricture is a true stenosis; and providing the digital angiographic image to a display device including markings identifying true stenoses.