F L Lizzi Center for Biomedical Engineering, Riverside Research Institute, New York, NY 10038, USA.
Ultrasound Med Biol. 2010 Mar;36(3):361-75. doi: 10.1016/j.ultrasmedbio.2009.10.007. Epub 2010 Feb 4.
High-frequency ultrasound (HFU) offers a means of investigating biologic tissue at the microscopic level. High-frequency, three-dimensional (3-D) quantitative-ultrasound (QUS) methods were developed to characterize freshly-dissected lymph nodes of cancer patients. Three-dimensional ultrasound data were acquired from lymph nodes using a 25.6-MHz center-frequency transducer. Each node was inked prior to tissue fixation to recover orientation after sectioning for 3-D histologic evaluation. Backscattered echo signals were processed using 3-D cylindrical regions-of-interest to yield four QUS estimates associated with tissue microstructure (i.e., effective scatterer size, acoustic concentration, intercept and slope). QUS estimates were computed following established methods using two scattering models. In this study, 46 lymph nodes acquired from 27 patients diagnosed with colon cancer were processed. Results revealed that fully-metastatic nodes could be perfectly differentiated from cancer-free nodes using slope or scatterer-size estimates. Specifically, results indicated that metastatic nodes had an average effective scatterer size (i.e., 37.1 +/- 1.7 microm) significantly larger (p < 0.05) than that in cancer-free nodes (i.e., 26 +/- 3.3 microm). Therefore, the 3-D QUS methods could provide a useful means of identifying small metastatic foci in dissected lymph nodes that might not be detectable using current standard pathology procedures.
高频超声（HFU）提供了一种在微观水平上研究生物组织的手段。高频三维（3-D）定量超声（QUS）方法被开发用于描述癌症患者新鲜解剖的淋巴结。使用中心频率为 25.6MHz 的换能器从淋巴结获取三维超声数据。每个节点在组织固定之前用墨水标记，以便在用于 3-D 组织学评估的切片后恢复方向。使用 3-D 圆柱感兴趣区处理背向散射回波信号，以产生与组织微观结构相关的四个 QUS 估计值（即有效散射体大小、声聚集、截距和斜率）。使用两种散射模型，按照既定方法计算 QUS 估计值。在这项研究中，从 27 名被诊断患有结肠癌的患者中处理了 46 个淋巴结。结果表明，使用斜率或散射体大小估计值可以完美地区分完全转移性节点和无癌节点。具体而言，结果表明转移性节点的平均有效散射体大小（即 37.1 +/- 1.7 微米）明显大于无癌节点（即 26 +/- 3.3 微米）（p < 0.05）。因此，3-D QUS 方法可以提供一种有用的手段来识别在当前标准病理学程序中可能无法检测到的解剖淋巴结中的小转移性焦点。
