An automatic method for rib ordering and pairing in 3D medical images

Automatic labeling of ribs in medical images of the chest has many applications that aid oncology and fracture evaluation. We present a novel algorithmic approach to label ribs independent of the rib extraction method adopted. The relative axial distance between rib points in a specified neighborhood is minimized within the least squares framework to obtain rib ordering. Subsequently, we model that the ribs on the same side are held in order by a spring system and treat the distance-based affinity between contralateral ribs as a magnetic attraction. Minimizing the total potential energy of the spring-magnet system to equilibrium establishes correct rib pairing subject to the ordering and enables accurate rib labeling.