This paper is focused on analysis of possible key features of atherosclerotic plaques displayed in B-images. There are two main aims: How to distinct normal and stenosis and how to compare stenosis in B-image in comparison with histological patterns. We have a set of B-images and corresponding histological patterns of atherosclerotic plaques which caused ischemic stroke. The goal of the paper is to investigate which features in B-images should be reliable and clear to distinct normal and stenosis and also which features could be compare with histological to determine ischemic stroke risk. There are some limitations in B-images such as complex structure and noise. Finding the reliable features is crucial step to create an expert system based on the analysis of these features. The output of the expert system should be set to probability of stenosis risk according to features of atherosclerotic plaque properties as rule base. The presented paper is a pilot study.