Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.
Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, USA.
Urolithiasis. 2019 Apr;47(2):181-188. doi: 10.1007/s00240-018-1036-z. Epub 2018 Jan 22.
Ultrasound imaging for kidney stones suffers from poorer sensitivity, diminished specificity, and overestimation of stone size compared to computed tomography (CT). The purpose of this study was to demonstrate in vitro feasibility of novel ultrasound imaging methods comparing traditional B-mode to advanced beamforming techniques including plane wave synthetic focusing (PWSF), short-lag spatial coherence (SLSC) imaging, mid-lag spatial coherence (MLSC) imaging with incoherent compounding, and aperture domain model image reconstruction (ADMIRE). The ultrasound techniques were evaluated using a research-based ultrasound system applied to an in vitro kidney stone model at 4 and 8 cm depths. Stone diameter sizing and stone contrast were compared among the different techniques. Analysis of variance was used to analyze the differences among group means, with p < 0.05 considered significant, and a Student's t test was used to compare each method with B-mode, with p < 0.0025 considered significant. All stones were detectable with each method. MLSC performed best with stone sizing and stone contrast compared to B-mode. On average, B-mode sizing error ± SD was > 1 mm (1.2 ± 1.1 mm), while those for PWSF, ADMIRE, and MLSC were < 1 mm (- 0.3 ± 2.9 mm, 0.6 ± 0.8, 0.8 ± 0.8, respectively). Subjectively, MLSC appeared to suppress the entire background thus highlighting only the stone. The ADMIRE and SLSC techniques appeared to highlight the stone shadow relative to the background. The detection and sizing of stones in vitro are feasible with advanced beamforming methods with ultrasound. Future work will include imaging stones at greater depths and evaluating the performance of these methods in human stone formers.
超声成像是一种常用的肾结石诊断方法，但与计算机断层扫描（CT）相比，其敏感性较低，特异性较差，并且可能高估结石大小。本研究旨在展示新型超声成像方法的体外可行性，将传统的 B 模式与先进的波束形成技术（包括平面波合成聚焦（PWSF）、短延迟空间相干（SLSC）成像、具有非相干复合的中延迟空间相干（MLSC）成像和孔径域模型图像重建（ADMIRE））进行比较。使用研究型超声系统在 4cm 和 8cm 深度的体外肾结石模型上评估超声技术。比较了不同技术的结石直径测量和结石对比度。使用方差分析比较组间均值的差异，p<0.05 认为差异有统计学意义，使用学生 t 检验比较每种方法与 B 模式的差异，p<0.0025 认为差异有统计学意义。所有结石均可以通过每种方法检测到。与 B 模式相比，MLSC 在结石大小和对比度方面表现最佳。平均而言，B 模式的尺寸误差 ± 标准差大于 1mm（1.2 ± 1.1mm），而 PWSF、ADMIRE 和 MLSC 的尺寸误差小于 1mm（-0.3 ± 2.9mm、0.6 ± 0.8mm、0.8 ± 0.8mm）。主观上，MLSC 似乎抑制了整个背景，从而仅突出结石。ADMIRE 和 SLSC 技术似乎突出了结石相对于背景的阴影。通过超声，先进的波束形成方法可实现结石的体外检测和测量。未来的工作将包括在更大深度成像结石，并评估这些方法在人类结石形成者中的性能。
