Combining Transversal and Longitudinal Registration in IVUS Studies

Intravascular ultrasound (IVUS) is a widely used imaging technique for atherosclerotic plaque assessment, interventionist guidance, stent deploy visualization and, lately, as tissue characterization tool. Some IVUS applications solve the problem of transducer motion by gating a particular phase of the study while others, such as elastography or spatio-temporal vessel reconstruction, combine image data from different cardiac phases, for which the gating solution is not enough. In the latter, it is mandatory for the structures in different cardiac phases to be aligned (cross-sectional registration) and in the correct position along the vessel axis (longitudinal registration). In this paper, a novel method for transversal and longitudinal registration is presented, which minimizes the correlation of the structures between images in a local set of frames. To assess the performance of this method, frames immediately after carina bifurcation were marked at different cardiac phases and the error between registrations was measured. The results shown a longitudinal registration error of 0.3827 ±0.8250 frames.