Abstract: To develop a new means of quantitating iipid deposits in vivo the authors performed intravascular ultrasound (IVUS) imaging on twenty atherosclerotic male New Zealand White rabbits, measured the sectional area and thickness of the plaques, the lumen area and diameter in lesion arteries. The results revealed that all of the rabbits were found with lipid deposits with the features of hypoechosic areas in IVUS image that adhered to the inner of the arterial walls and were coincided with the histopathologic observations. The sec tional area of the plaques was 0.71±0.26mm², and the thickness was 0.27±0.09mm. The authors consider that IVUS imaging would be a new means of quantitative assessment for the lipid deposits in vivo.