A plaque is a collection of cholesterol and associated material which can be of different types. It is called ulcerated if its surface is irregular
like that of an ulcer on the skin. The importance lies in the fact that such plaques are prone to development of clots on their surface with subsequent further blockage of the vessel and its serious consequences. Angiography is the only tested method of its identification. Newer methods in the pipeline include MRI imaging and ultrasonography.