Division of Experimental Medicine, Department of Medicine, Faculty of Medicine, Research Institute of the McGill University Health Centre (MUHC), McGill University, Montreal, QC, Canada.
Department of Pathology and Laboratory Medicine, University of Ottawa Heart Institute, Ottawa, ON, Canada.
Eur J Vasc Endovasc Surg. 2019 Nov;58(5):654-663. doi: 10.1016/j.ejvs.2019.07.015. Epub 2019 Sep 19.
Atherosclerosis and its thrombotic complications are major causes of morbidity and mortality worldwide. Plaque stability assessment is considered to be important for both clinical and fundamental applications. The current gold standard method to investigate plaque stability is performed by histological assessment of plaque features using semi-quantitative classifications. However, these assessments can be limited by subjectivity and variability. Thus, the aim was to develop a new digital image analysis method to measure quantitatively individual plaque features that is more precise than existing semi-quantitative methods.
A quantitative method was developed using Image Pro Primer software. Carotid plaque specimens were obtained from patients who underwent carotid endarterectomy and categorised according to stability (definitely stable, probably stable, probably unstable, definitely unstable) based on the gold standard semi-quantitative method that assesses 10 histological plaque features. Using the new quantitative method, plaque features (n = 15) from each stability grade were then analysed by two independent raters. For the semi-quantitative analysis, quadratic weighted Cohen's kappa was used to test intra- and inter-rater reliability, while for the quantitative analysis, intraclass correlation coefficients (ICCs) were assessed.
Intra-rater reliability demonstrated almost perfect agreement between both methods (Cohen's kappa range 0.831-0.969, ICC range 0.848-1.000). However, inter-rater reliability demonstrated mainly fair to moderate agreement (Cohen's kappa range 0.341-0.778) for the semi-quantitative analysis, while the digital image analysis method performed most optimally regarding reproducibility, yielding high ICCs close to 1 (ICC range 0.816-0.999). Using quantitative measurements, a statistically significant proportion of the individual plaque features (p < .05) were re-classified from one grade to another (shift by one) under the semi-quantitative classification.
A new quantitative digital image analysis was developed for the accurate assessment of histological plaque features, which demonstrated higher precision than the gold standard semi-quantitative methods, as measured by between and within rater analysis. Moreover, quantitative image analysis of histological plaque features provided more detailed insight into plaque morphology and composition.
动脉粥样硬化及其血栓并发症是全球发病率和死亡率的主要原因。斑块稳定性评估对于临床和基础应用都很重要。目前，评估斑块稳定性的金标准方法是通过半定量分类对斑块特征进行组织学评估。然而，这些评估可能受到主观性和变异性的限制。因此，本研究旨在开发一种新的数字图像分析方法，以定量测量个体斑块特征，比现有的半定量方法更精确。
使用 Image Pro Primer 软件开发了一种定量方法。从接受颈动脉内膜切除术的患者中获得颈动脉斑块标本，并根据评估 10 种组织学斑块特征的金标准半定量方法将其分为稳定性（肯定稳定、可能稳定、可能不稳定、肯定不稳定）。使用新的定量方法，然后由两名独立的评估者分析每个稳定性等级的斑块特征（n=15）。对于半定量分析，使用二次加权 Cohen's kappa 检验评估组内和组间的可靠性，而对于定量分析，使用组内相关系数（ICC）进行评估。
组内可靠性表明两种方法之间几乎存在完美的一致性（Cohen's kappa 范围为 0.831-0.969，ICC 范围为 0.848-1.000）。然而，组间可靠性表明半定量分析主要是良好到中度的一致性（Cohen's kappa 范围为 0.341-0.778），而数字图像分析方法在可重复性方面表现最佳，产生接近 1 的高 ICC（ICC 范围为 0.816-0.999）。使用定量测量，在半定量分类下，个体斑块特征中有相当大比例（p<.05）从一个等级重新分类为另一个等级（移位一级）。
开发了一种新的定量数字图像分析方法，用于准确评估组织学斑块特征，与金标准半定量方法相比，该方法在组内和组间分析中表现出更高的精度。此外，对组织学斑块特征的定量图像分析提供了更详细的斑块形态和组成信息。
