Ultrasound spatial compounding via registration of 2D slices into 3D volume

Spatial compounding is very important for improving the quality of the 3D ultrasound data. The key to effective spatial compounding is accurate registration between the compounded data. In this paper, a new nonlinear deformable registration method for ultrasound spatial compounding is proposed. This novel method includes two steps. First, multiresolution cubic B-spline registration (MRBR) is applied to determine global and local nonlinear deformations following rigid registrations. Then 2D slice images are divided into partly overlapped sub-images to estimate the residual local deformations. Correlation ratio (CR) is used as the similarity metric. The results of in-vitro and in vivo trials demonstrated that we could get accurate registration using the new technique, which shows great promise for reducing tissue motion and local deformation in spatial compounding.