Feasibility of Swept Synthetic Aperture Ultrasound Imaging.
Feasibility of Swept Synthetic Aperture Ultrasound Imaging.
复制标题
DOI：
10.1109/tmi.2016.2524992
复制
发表时间：
2016-07
影响因子：
10.6
通讯作者：
Trahey GE
中科院分区：
文献类型：
--
作者：
Bottenus N;Long W;Zhang HK;Jakovljevic M;Bradway DP;Boctor EM;Trahey GE
超声图像质量通常固有地受到成像换能器的物理尺寸的限制。我们假设，通过在一定范围的孔径位置上收集合成孔径数据集，同时精确跟踪换能器的位置和方向，我们可以合成大的有效孔径，以产生具有更高分辨率和目标探测能力的图像。我们分析了相干信号求和的两个最大限制因素：像差和机械不确定性。以犬腹壁为模型相位屏，实验观测到扫描位置的有效到达时间误差范围为18.3 ns到58 ns(均方根误差)。通过产生杂波的组织，我们观察到与对照组相比，分辨率提高了72.9%，而旁瓣幅度仅增加了3.75分贝。我们提出了一个仿真模型来研究校准误差和机械抖动误差对综合点扩展函数的影响。探讨了这些误差在每个成像维度上的相对影响，说明了方位相对于点扩散函数的重要性。我们提出了一种利用传统的一维阵列换能器和超声研究扫描仪进行扫描合成孔径成像的原型装置。在44.2度扫描条件下，点目标横向和轴向重建精度分别为82.8μm和17.8μm，均在仿真模型可接受的性能范围内。在活体和胎儿体模中显示了分辨率、对比度和对比度噪声比的改善。
Ultrasound image quality is often inherently limited by the physical dimensions of the imaging transducer. We hypothesize that, by collecting synthetic aperture data sets over a range of aperture positions while precisely tracking the position and orientation of the transducer, we can synthesize large effective apertures to produce images with improved resolution and target detectability. We analyze the two largest limiting factors for coherent signal summation: aberration and mechanical uncertainty. Using an excised canine abdominal wall as a model phase screen, we experimentally observed an effective arrival time error ranging from 18.3 ns to 58 ns (root-mean-square error) across the swept positions. Through this clutter-generating tissue, we observed a 72.9% improvement in resolution with only a 3.75 dB increase in side lobe amplitude compared to the control case. We present a simulation model to study the effect of calibration and mechanical jitter errors on the synthesized point spread function. The relative effects of these errors in each imaging dimension are explored, showing the importance of orientation relative to the point spread function. We present a prototype device for performing swept synthetic aperture imaging using a conventional 1-D array transducer and ultrasound research scanner. Point target reconstruction error for a 44.2 degree sweep shows a reconstruction precision of 82.8 μm and 17.8 μm in the lateral and axial dimensions respectively, within the acceptable performance bounds of the simulation model. Improvements in resolution, contrast and contrast-to-noise ratio are demonstrated in vivo and in a fetal phantom.