Moghimirad Elahe, Villagomez Hoyos Carlos A, Mahloojifar Ali, Mohammadzadeh Asl Babak, Jensen Jorgen Arendt
IEEE Trans Ultrason Ferroelectr Freq Control. 2016 Dec;63(12):2018-2030. doi: 10.1109/TUFFC.2016.2606878. Epub 2016 Sep 7.
An efficient Fourier beamformation algorithm is presented for multistatic synthetic aperture ultrasound imaging using virtual sources. The concept is based on the frequency domain wavenumber algorithm from radar and sonar and is extended to a multielement transmit/receive configuration using virtual sources. Window functions are used to extract the azimuth processing bandwidths and weight the data to reduce side lobes in the final image. Field II simulated data and SARUS (Synthetic Aperture Real-time Ultrasound System) measured data are used to evaluate the results in terms of point spread function, resolution, contrast, signal-to-noise ratio, and processing time. Lateral resolutions of 0.53 and 0.66 mm are obtained for Fourier Beamformation Using Virtual Sources (FBV) and delay and sum (DAS) on point target simulated data. Corresponding axial resolutions are 0.21 mm for FBV and 0.20 mm for DAS. The results are also consistent over different depths evaluated using a simulated phantom containing several point targets at different depths. FBV shows a better lateral resolution at all depths, and the axial and cystic resolutions of -6, -12, and -20 dB are almost the same for FBV and DAS. To evaluate the cyst phantom metrics, three different criteria of power ratio, contrast ratio, and contrast-to-noise ratio have been used. Results show that the algorithms have a different performance in the cyst center and near the boundary. FBV has a better performance near the boundary; however, DAS is better in the more central area of the cyst. Measured data from phantoms are also used for evaluation. The results confirm applicability of FBV in ultrasound, and 20 times less processing time is attained in comparison with DAS. Evaluating the results over a wide variety of parameters and having almost the same results for simulated and measured data demonstrates the ability of FBV in preserving the quality of image as DAS, while providing a more efficient algorithm with 20 times less computations.
提出了一种用于多静态合成孔径超声成像的高效傅里叶波束形成算法，该算法使用虚拟源。该概念基于雷达和声纳的频域波数算法，并扩展到使用虚拟源的多元素发射/接收配置。窗口函数用于提取方位处理带宽并对数据进行加权，以减少最终图像中的旁瓣。使用Field II模拟数据和SARUS（合成孔径实时超声系统）测量数据，从点扩散函数、分辨率、对比度、信噪比和处理时间等方面对结果进行评估。对于点目标模拟数据，使用虚拟源的傅里叶波束形成（FBV）和延迟求和（DAS）分别获得了0.53和0.66毫米的横向分辨率。FBV对应的轴向分辨率为0.21毫米，DAS为0.20毫米。在使用包含不同深度多个点目标的模拟体模评估的不同深度上，结果也一致。FBV在所有深度都显示出更好的横向分辨率，并且FBV和DAS在-6、-12和-20 dB的轴向分辨率和囊性分辨率几乎相同。为了评估囊肿体模指标，使用了功率比、对比度比和对比度噪声比三种不同标准。结果表明，这些算法在囊肿中心和边界附近具有不同的性能。FBV在边界附近性能更好；然而，DAS在囊肿的更中心区域表现更好。来自体模的测量数据也用于评估。结果证实了FBV在超声中的适用性，与DAS相比，处理时间减少了20倍。在各种参数上评估结果，并且模拟数据和测量数据的结果几乎相同，这证明了FBV在保持与DAS相同图像质量的同时，能够提供一种计算量减少20倍的更高效算法。
