Image processing approaches for analysis of clinical duplex ultrasonography

We are developing simple and efficient tools for assessing qualitative and quantitative information on 3D carotid anatomy and velocity distributions by integrating 2D color Doppler and B-mode images. Transverse color Doppler images of the carotid bifurcation were obtained during relatively uniform, manual scanning of the transducer. Longitudinal views were also recorded. The transverse images obtained at or near systole were automatically extracted by analysis of the flow data. The flow regions in the lumen in the individual images were segmented using the interface between the flow colored and non-colored, i.e., grey level, regions in the systolic images. A 3D volume was generated by stacking and interpolating each component. Representative longitudinal projections were then obtained by resampling this 3D volume according to the vessel centerline and integrating longitudinal slices of this volume to take into account the transducer resolution. The computed longitudinal images were matched to the longitudinally acquired images using a Procrustes technique, and a registered 3D reconstruction of the flow patterns, lumen and intima was obtained. Preliminary results show that the computed longitudinal projections of the 3D reconstructed volume are globally consistent with the acquired scans.