Abdominal imaging suffers from a particularly difficult acoustic environment - targets are located deep and overlying tissue layers with varying properties generate acoustic clutter. Increasing array size can overcome the penetration and lateral resolution problems in ideal conditions, but how the impact of clutter scales with increasing array extent is unknown and may limit the benefits in vivo. Previous ex vivo experimental work showed the promise of large arrays but was technically limited to a length of 6.4 cm and to only partial sampling of the array elements. We present an extension of those studies using the Fullwave simulation tool to create a 10 cm × 2 cm matrix array with full lateral element sampling. We used a numerical model of the abdomen based on maps of tissue acoustical properties and found that propagation through the modeled abdominal layers generated on average 25.4 ns of aberration and 0.74 cm of reverberation clutter across the array extent. Growing the full aperture from 2 cm to 10 cm improved contrast by 8.6 dB and contrast-to-noise ratio by 22.9% in addition to significantly improving target resolution. Alternative array strategies that may be useful for implementation - mismatched aperture sizes or a swept synthetic aperture - also produced improved quality with growing aperture size. These results motivate the development of larger diagnostic imaging arrays for the purpose of highresolution imaging in challenging environments.

中文翻译：

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声杂波对大阵腹部成像的影响。


腹部成像面临着特别困难的声学环境 - 目标位于深处，并且具有不同特性的覆盖组织层会产生声学杂乱。增加阵列尺寸可以克服理想条件下的穿透和横向分辨率问题，但杂波规模如何随着阵列范围的增加而产生影响尚不清楚，并且可能会限制体内的好处。之前的离体实验工作显示了大型阵列的前景，但技术上仅限于 6.4 厘米的长度，并且只能对阵列元件进行部分采样。我们使用 Fullwave 模拟工具对这些研究进行了扩展，以创建具有全横向元件采样的 10 cm × 2 cm 矩阵阵列。我们使用基于组织声学特性图的腹部数值模型，发现通过建模的腹部层的传播在整个阵列范围内产生平均 25.4 ns 的像差和 0.74 cm 的混响杂波。将全孔径从 2 厘米增大到 10 厘米，除了显着提高目标分辨率外，对比度还提高了 8.6 dB，对比度噪声比提高了 22.9%。可能对实施有用的替代阵列策略——不匹配的孔径尺寸或扫描合成孔径——也随着孔径尺寸的增大而提高了质量。这些结果推动了更大的诊断成像阵列的开发，以便在具有挑战性的环境中实现高分辨率成像。