In conventional ultrasound imaging systems the image quality (resolution and contrast) is degraded due to the presence of image speckle. The received echo signal is a sum of signals reflected by a large number of small scatterers randomly located within a resolution cell. They cause constructive and destructive phase interference at the receiving array. Due to the speckle the small image features (size, shape and type of atherosclerosis lesions) can often be difficult to determine. One of the ways to reduce the speckle noise is multi-angle spatial compound imaging (MACI). In a MACI system the final image is a combination of independent or partially correlated images obtained by scanning the region of interest (ROI) with several different beam angles. In result of combining the speckle noise in a MACI image is reduced and the image quality is sufficiently improved.