3-D compound imaging with refraction and motion correction

The early goal of multiview imaging was delineation of quasi-specular image boundaries. Medical compound imaging was partially replaced because of resolution loss by refraction, misregistration, and tissue motion, and completely replaced due to incompatibility with real-time imaging. Three potential improvements in: boundary delineation, volumetric contrast-to-noise ratio, and Doppler anisotropy reduction (BC&D) have remained an attraction of compounding. Now marketed, in-plane compounding in real-time and in extended field of view imaging offer the potential for in-plane, image-based reregistration of multiple views. Image volume-based registration (IVBaR) of separate angular views in 3-D data sets allows full 3-D displacement corrections. Compounding out of the image plane (elevational compounding) increases the number of independent views, increasing potential yield from improvements BC&D. Our work has been in elevational compounding with conventional linear arrays, in contact with, and partially moving the proximal tissues. IVBaR using the mutual information metric and thin plate spline interpolation of warped volumes has produced exceptional reclamation of spatial resolution along with the expected improvements BC&D. Full-volume, warped registration, and a faster, subvolume registration have been compared in vivo and with realistic beam aberrations in test objects. [Work supported in part by PHS Grant No. R01HL54201 from the NHLBI.]