Most studies related with plaque histopathology and/or morphology are based on the gray scale intravascular ultrasound (IVUS) and autopsy findings, although IVUS is limited for differentiating echolucent areas, and tissue shrinkage almost always occur during tissue fixation. In addition, autopsy studies can not establish the causal relationship between the autopsy findings and the clinical findings. Spectral analysis of the IVUS radiofrequency data may be a new and useful tool because it allows detailed assessment of plaque composition in vivo, with a high predictive accuracy of 87.1% to 96.5% in fibrous, fibrofatty, calcified and necrotic core regions with performing tissue mapping and geometric assessment like that for classic gray scale IVUS. This new imaging technique offers clear benefits compared with the results of classic IVUS and autopsy studies. This review will briefly discuss the methodology of spectral analysis of the IVUS radiofrequency data, the recent clinical studies that have used this technique and the future perspectives.