Plaque composition is a major factor that determines plaque vulnerability. Intravascular ultrasound (IVUS) and spectral analysis of the radiofrequency signal provide an in-vivo tissue characterization of atherosclerotic plaques, known as Virtual Histology (VH-IVUS). In VH-IVUS analysis, four histological tissue components are classified; fibrous, fibro/fatty, necrotic core and calcium. Existing technology determines only the area of each component within the plaque.
