A computer-assisted ultrasound imaging system (100) wherein an ultrasound device (4) is provided with an ultrasound probe (3) for capturing a plurality of two-dimensional ultrasound images of a concerned region. The system processes the acquired ultrasound images in order to obtain a three-dimensional compound ultrasound graphic reconstruction (C), which is compared with a three-dimensional pseudo ultrasound image (B) obtained by processing a plurality of two-dimensional images obtained by means of X-ray or magnetic resonance techniques (A). Following the adjustment procedure with a first spot-test method or, alternatively, with a second structural method, the image C is superimposed on image A.
