Intraplaque hemorrhage (IPH) is an important co-factor for plaque progression and rupture. So far noninvasive MRI has shown promise for the in-vivo identification of IPH and for the prediction of plaque instability. Intravascular imaging techniques such as intravascular ultrasound or optical coherence tomography (OCT) cannot distinguish between IPH and other plaque components. However, OCT has the unique ability to identify microvessels located in the lipid core of atherosclerotic plaque due to its high resolution (around 20 μm). Microvessels are known to be the main source of blood extravasation due to their anatomically compromised structure. Coronary plaques with a high microvessel density undergo rapid plaque progression and are often associated with other features of plaque instability such as inflammatory cells. The combination of data from both MRI and OCT studies will allow a better understanding of the mechanism of plaque destabilization and the pathophysiology of cardiovascular events.