Xu Yijun, Yue Yaoting, Wang Hao, Gu Wenting, Li Boyi, Chen Yaqing, Liu Xin
Academy for Engineering and Technology, Fudan University, Shanghai, 200433, China.
School of Communication and Information Engineering, Shanghai University, Shanghai, 200444, China.
Med Biol Eng Comput. 2025 Apr 29. doi: 10.1007/s11517-025-03364-4.
Coherent plane-wave compounding, while efficient for ultrafast ultrasound imaging, yields lower image quality due to unfocused waves. Delay multiply-and-sum (DMAS) beamformer is one of the representative coherence-based methods which can improve images quality, but suffers from poor speckle quality brought by oversuppression. Current DMAS-based methods involve trade-offs between contrast, resolution, and speckle preservation. To overcome this limitation, a new beamformer method combining the null subtraction imaging (NSI) and DMAS is investigated. The proposed method explores the DMAS on different beamformers which employs NSI and delay and sum (DAS) at receive and do multiply-and-sum on different beamformers across transmitting dimension, thereby simultaneously possessing the speckle quality of DAS and the high resolution of NSI. The effectiveness of the proposed method is evaluated through simulation, phantom, and in vivo datasets. From the experimental study, in comparison with NSI, the proposed method has improved contrast ratio by 10.02%, speckle signal-to-noise ratio by 45.19%, and generalized contrast-to-noise ratio by 12.37%. The method has also improved the full width at half maximum by up to 0.24 mm. The results indicate that the proposed method achieves better resolution and contrast, while also alleviating the issue of excessive compression.
相干平面波复合技术虽然在超快超声成像中效率较高，但由于波未聚焦，导致图像质量较低。延迟相乘求和（DMAS）波束形成器是基于相干性的代表性方法之一，它可以提高图像质量，但会因过度抑制而导致散斑质量较差。当前基于DMAS的方法在对比度、分辨率和散斑保留之间存在权衡。为了克服这一限制，研究了一种将相消成像（NSI）和DMAS相结合的新波束形成器方法。所提出的方法在不同的波束形成器上探索DMAS，这些波束形成器在接收端采用NSI和延迟求和（DAS），并在发射维度上对不同的波束形成器进行相乘求和，从而同时具备DAS的散斑质量和NSI的高分辨率。通过模拟、体模和体内数据集评估了所提出方法的有效性。从实验研究来看，与NSI相比，所提出的方法对比度提高了10.02%，散斑信噪比提高了45.19%，广义对比度噪声比提高了12.37%。该方法还将半高宽提高了0.24毫米。结果表明，所提出的方法实现了更好的分辨率和对比度，同时也缓解了过度压缩的问题。
