适用于曲线换能器的体内分布式像差校正的透镜感知可微分波束形成
Lens-Aware Differentiable Beamforming for In Vivo Distributed Aberration Correction with Curvilinear Transducers
AI总结：
本研究提出透镜感知可微分波束形成方法，将超声自动聚焦扩展至曲线阵列，通过321次人体肝脏采集验证，显著提升图像质量，为临床分布式像差校正技术提供潜力。
AI中文摘要：
本研究将超声自动聚焦通过共中心点相位误差优化扩展至支持曲线阵列几何结构，采用可微分弯曲射线追踪方法，通过考虑换能器透镜引起的折射，基于局部声速估计执行迭代的基于模型的像差校正。通过校准声速仿体在计算机模拟中验证模型，并在体内人体肝脏图像上验证。本研究是首次对分布式像差校正方法进行大规模体内验证，涉及81名高BMI人体肝脏受试者的321次采集。在含无回声区域的采集图像中，平均对比度和CNR（对比噪声比）分别提升$1.42 \text{±} 1.63$ dB（+18.4%）和$0.09 \text{±} 0.14$（+10.3%）；在多个图像质量指标上也观察到平均提升：斑点亮度（+20.1%）、相干因子（+13.1%）、滞后1相干性（+2.6%）、共中心点相关系数（+0.7%）、共中心点相位误差（-9.1%，数值越低越好），所有指标提升均具有统计学显著性。此外，目标结构和可见性也观察到显著的定性提升。这些结果表明，未来基于超声自动聚焦的临床分布式像差校正技术具有应用潜力。
英文摘要：
We previously introduced ultrasound autofocusing, an iterative model-based aberration correction technique that estimates local sound speed and incorporates it into beamforming to correct image distortion from heterogeneous media. In this work, we extend ultrasound autofocusing to curvilinear arrays and introduce advancements to the underlying model. A differentiable bent-ray tracing approach accounts for refraction through the transducer lens, while a new adaptive-grid initialization accounts for changes in speckle position with sound speed. The method is validated in silico and in calibrated sound speed phantoms. Our distributed aberration-correction method is then applied to a first large-scale in vivo evaluation comprising 313 liver acquisitions from 76 high-BMI human subjects. In images containing anechoic regions, contrast and CNR improved by $1.38 \pm 1.60$ dB (+18.0%) and $0.09 \pm 0.14$ (+10.2%), respectively. Improvements were also observed in speckle brightness (+20.3%), coherence factor (+13.1%), lag-one coherence (+2.7%), common-midpoint correlation coefficient (+0.7%), and common-midpoint phase error (-9.1%; lower is better), with all metric improvements statistically significant. Target structure and visibility also improved significantly. These results demonstrate the potential of ultrasound autofocusing for clinically applicable distributed aberration correction.
