Analysis of contrast-enhanced intravascular ultrasound images for the assessment of coronary plaque neoangiogenesis: another step closer to the identification of the vulnerable plaque.

Atherosclerotic cardiovascular disease (CVD), primarily manifested as heart attacks and strokes, remains the main cause of death in the developed countries and is rapidly increasing in the developing world. Early detection and aggressive treatment of hidden (asymptomatic) atherosclerotic plaques that cause heart attack or stroke are most needed. However, existing clinical tools are not sufficient to address this need. Intravascular ultrasound (IVUS) is a catheter-based medical imaging tool that is capable of providing cross-sectional images of arteries. It is by far the most powerful clinical tool available for characterization of atherosclerotic plaques. However, existing IVUS is unable to detect plaque inflammation which is a key factor in complications of atherosclerotic plaques. Contrast enhanced IVUS (CE-IVUS) for detection of Vasa Vasorum (VV), microvessles that feed the vessel wall, can indirectly image plaque inflammation and thereby significantly increase the diagnostic power of IVUS. Several studies have shown that the density of VV in the atherosclerotic plaques is strongly correlated with the intensity of plaque inflammation and related processes which lead to plaque destabilization and rupture (the Vulnerable Plaque). Therefore the detection and measurement of VV in plaque, and leakage of blood from VV into plaques using CE-IVUS, can enable the development of an index for plaque vulnerability. In this paper, we present a review of our original work on coronary VV imaging, discuss subsequent reports by others, and also present the latest on the detection of VV based on CE-IVUS.