New Quantitative Digital Image Analysis Method of Histological Features of Carotid Atherosclerotic Plaques
Huaien Zheng1, Karina Gasbarrino1, John P Veinot2
1Division of Experimental Medicine, Department of Medicine, Faculty of Medicine, Research Institute of the McGill University Health Centre (MUHC), McGill University, Montreal, QC, Canada.
Insights
A new digital image analysis method precisely measures atherosclerotic plaque features, outperforming traditional semi-quantitative assessments for improved plaque stability evaluation. This quantitative approach enhances reproducibility and provides deeper insights into plaque morphology.
Area of Science:
- Cardiovascular Research
- Biomedical Imaging
- Pathology
Background:
- Atherosclerosis and its thrombotic complications are leading causes of global morbidity and mortality.
- Accurate assessment of atherosclerotic plaque stability is crucial for clinical and fundamental research.
- Current histological assessments rely on semi-quantitative methods, which are prone to subjectivity and variability.
Purpose of the Study:
- To develop a novel digital image analysis method for precise quantitative measurement of individual atherosclerotic plaque features.
- To compare the reproducibility and precision of the new quantitative method against the established semi-quantitative gold standard.
Main Methods:
- A quantitative digital image analysis method was developed using Image Pro Primer software.
- Carotid plaque specimens were analyzed by two independent raters for both semi-quantitative and quantitative assessments.
- Intra- and inter-rater reliability were evaluated using Cohen's kappa for semi-quantitative analysis and intraclass correlation coefficients (ICCs) for quantitative analysis.
Main Results:
- Both methods showed high intra-rater reliability (Cohen's kappa: 0.831-0.969; ICCs: 0.848-1.000).
- The quantitative digital image analysis method demonstrated superior inter-rater reliability (ICCs: 0.816-0.999) compared to the semi-quantitative method (Cohen's kappa: 0.341-0.778).
- Quantitative measurements led to statistically significant re-classifications of plaque features between stability grades.
Conclusions:
- A new quantitative digital image analysis method offers higher precision for assessing histological plaque features compared to traditional semi-quantitative methods.
- This quantitative approach enhances reproducibility in plaque stability assessment.
- Digital image analysis provides more detailed insights into atherosclerotic plaque morphology and composition.
Objective:
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.
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.
Results:
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.
Conclusion:
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.
Related Concept Videos
01:25Imaging Studies for Cardiovascular System VI: Calcium -Scoring CT
01:30Atherosclerosis I: Introduction
01:27Atherosclerosis II: Clinical Manifestations and Diagnostic Tests