Cardinal Points Symmetry Landmarks Distribution Model for Segmentation of Region of Interest in Simulated B-Mode Ultrasound Carotid Artery Images

Measurement accuracy and understanding of geometry of Common Carotid Artery (CCA) play an important role in carotid atherosclerosis assessment and management. In order to device techniques that can accurately analyze the effects of plaques on the carotid artery, a model that can sufficiently segment the Region of Interest (ROI) in the B-mode ultrasound image of carotid artery is needed. In this paper, a new Cardinal Points Symmetry Landmarks Distribution Model (CPS-LDM) to sufficiently segment the ROI in the carotid artery B-mode ultrasound imaged in the transverse plane is developed. The developed model employs a combination of fixed landmarks (FLs) and movable landmarks (MLs) to obtain the total landmarks (TLs) that can sufficiently segment the shape of the ROI of the carotid artery. Simulated ultrasound images are used. Four FLs are fixed on each of the four ROIs of the simulated carotid artery determined by the cardinal points North (N), South (S), East (E) and West (W) drawn on the ROIs of the carotid artery. The MLs are determined by the inter-cardinal directions such as North-East (NE), North-West (NW) and so on. The CPS-LDM equation developed allows us to visualize graphically the optimum number of points that can sufficiently segment the ROIs. ImageJ2 software was used to generate the Cartesian coordinates for each landmark which were then used to generate the Shape Space Pattern (SSP) of the carotid artery ready for further statistical analysis. The results showed that the CPS-LD model is sufficiently generic and adaptable to a variety of carotid artery B-mode ultrasound image simulated under different scenarios