Evaluation of a synthetic aperture technique for medical ultrasound imaging: Phantom and in vivo breast study

Various synthetic aperture (SA) techniques, which are capable of two-way dynamic focusing, have been proposed in medical ultrasound imaging since 1980s to overcome the limited spatial resolution of conventional dynamic receive focusing (DRF) techniques. However, the evaluation of SA techniques has not been extensively carried out with regard to its clinical performance. In this paper, the performance of the SA method is evaluated in comparison with the conventional DRF method with phantom and in vivo breast data. In SA images, the contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and penetration depth of phantom data were increased by 9.1%, 8.3 dB and 40.8%, respectively, compared to DRF images. The similar improvements were obtained with in vivo data where the CNR and SNR values were increased by 17.9% and 6.8 dB, respectively. From the subjective assessment of in vivo data, the SA method showed improved conspicuity, margin sharpness, contrast and spatial resolution. The results of these experiments showed that the SA method can improve the image quality both in phantom and in vivo data. In addition, the SA method showed potential diagnostic improvements, although further studies are needed.