Data from: Quantification and statistical analysis methods for vessel wall components from stained images with Masson's trichrome

Purpose: To develop a digital image processing method to quantify structural components (smooth muscle fibers and extracellular matrix) in the vessel wall stained with Masson’s trichrome, and a statistical method suitable for small sample sizes to analyze the results previously obtained. Methods: The quantification method comprises two stages. The pre-processing stage improves tissue image appearance and the vessel wall area is delimited. In the feature extraction stage, the vessel wall components are segmented by grouping pixels with a similar color. The area of each component is calculated by normalizing the number of pixels of each group by the vessel wall area. Statistical analyses are implemented by permutation tests, based on resampling without replacement from the set of the observed data to obtain a sampling distribution of an estimator. The implementation can be parallelized on a multicore machine to reduce execution time. Results: The methods have been tested on 48 vessel wall samples of the internal saphenous vein stained with Masson’s trichrome. The results show that the segmented areas are consistent with the perception of a team of doctors and demonstrate good correlation between the expert judgments and the measured parameters for evaluating vessel wall changes. Conclusion: The proposed methodology offers a powerful tool to quantify some components of the vessel wall. It is more objective, sensitive and accurate than the biochemical and qualitative methods traditionally used. The permutation tests are suitable statistical techniques to analyze the numerical measurements obtained when the underlying assumptions of the other statistical techniques are not met.

研究目的：开发一种数字图像处理方法，以量化经马森三色（Masson’s trichrome）染色的血管壁结构成分（平滑肌纤维与细胞外基质），并构建适配小样本量的统计分析方法，用于分析前述实验所得结果。
研究方法：该量化方法包含两个阶段。预处理阶段优化组织图像的视觉表现，并划定血管壁的感兴趣区域；特征提取阶段通过对颜色相似的像素进行聚类，实现血管壁各成分的分割。将各组像素的数量按血管壁总面积进行归一化后，即可计算得到各成分的面积。统计分析采用置换检验（permutation tests），其通过从观测数据集中无放回重采样以获取估计量的抽样分布来实现。该方法的实现可在多核计算机上并行运行，以缩短执行耗时。
研究结果：本方法已在48份经马森三色染色的隐静脉（internal saphenous vein）血管壁样本上完成测试。结果表明，分割得到的面积与临床医师团队的主观判断具有一致性，且专家评分与用于评估血管壁变化的测量参数之间存在良好的相关性。
研究结论：所提出的方法学为量化血管壁部分结构成分提供了强有力的工具。相较于传统使用的生化检测方法与定性分析方法，该方法具备更强的客观性、敏感性与准确性。当其他统计技术的底层假设无法满足时，置换检验是适配此类数值测量结果分析的合适统计方法。