Figure 4.

Cluster analysis for each region. (a) Pixels of each region were subjected to k-means clustering (two clusters for each region, red and blue) to discriminate between asymptomatic and symptomatic plaques. Region identity is coded by the border color. Clustering of different regions was performed independently. Difference between spectra of the blue and the red clusters (corresponding to cluster 1 and cluster 2) for (b) macrophages and (c) inner VSMCs regions of the DHB dataset.