Statin therapy, especially at intensive doses, is beneficial in atherosclerotic coronary disease. Detecting subtle plaque regression after statin therapy is difficult by coronary angiogram; intravascular ultrasound (IVUS) is a far better method. Volumetric IVUS has been used in statin trials to evaluate plaque regression. Intensive statin therapy in the REVERSAL Trial and ASTEROID Trial appeared to achieve better regression outcomes. Stable fibrous plaque is likely to be responsible for stable ischemia, while unstable plaque (large lipid core, calcified nodule and necrotic core), thin-cap fibroatheroma, plaque erosion and plaque rupture may be responsible for acute coronary syndrome (ACS). In vivo tissue characterization of plaque composition is therefore important, yet in this regard grayscale IVUS is insufficient. The development of Virtual Histology (VH) utilizing IVUS generated radiofrequency backscattering signals to virtually separate plaque composition into 4 components corresponding to histopathology has made possible in vivo assessment of plaque composition and stability. We believed plaque regression and VH-IVUS plaque modification with statin therapy could be statin dose dependent, and may affect clinical outcomes. This study was designed to prove our hypothesis, utilizing VH-IVUS.