Effect of subaperture beamforming on phase coherence imaging

摘要: High-frame-rate echocardiography using unfocused transmit beams and parallel receive beamforming is a promising method for evaluation of cardiac function, such as imaging rapid propagation vibration the heart wall resulting from electrical stimulation myocardium. In this technique, high temporal resolution realized at expense spatial contrast. The phase coherence factor has been developed to improve contrast in ultrasonography. It evaluates variance phases echo signals received by individual transducer elements after delay compensation, conventional delay-andsum process. However, suppresses speckle echoes because fluctuate result interference echoes. present study, receiving aperture was divided into several subapertures, delay-and-sum performed with respect each subaperture suppress scatterers except that focal point. After beamforming, obtained beamformed RF respective subapertures. By means procedure, undesirable echoes, which can interfere point, be suppressed suppression fluctuation caused avoided. effect high-frame-rate evaluated phantom. applying average intensity diffuse scattering medium significantly higher (-39.9 dB) than without (-48.7 dB). As resolution, width half-maximum lateral amplitude profile 1.06 mm. factor, improved significantly, achieved better 0.75 mm 0.78 beamforming.