5. Micromachined 1-3 Composite Single Element Transducers

Plaque rupture is the primary mechanism underlying acute coronary syndromes and stroke. The assessment of plaque vulnerability includes stenosis, lipid core and thin-cap fibroatheroma, intraplaque angiogenesis, and so on. Coronary occlusion and myocardial infarction usually evolve from mid-to-moderate stenosis of lipid-right lesions. In common cases, the vulnerable plaques are severely stenotic and appear to be ulcerated. Unfortunately, a high percentage of vulnerable plaques are also angiographically occult (non-stenotic), and these are responsible for a high proportion of ensuing cardiac events resulting in either fatalities or requiring further interventional treatment. Plaque composition characterization is of clinical importance in that it has been hypothesized that vulnerable plaques consisting of a lipid core with a fibrous cap are most likely to rupture, causing the formation of clots and serious clinical consequences such as stroke and heart attack. For this reason, detection and characterization of rupture prone plaques is one of the most active areas of research in cardiology and biomedical imaging.