Cross-sectional elastic imaging of arterial wall using intravascular ultrasonography

There have been several studies on the imaging of the distribution of the e lasticity of the arterial wall using intravascular ultrasonography (IVUS). In those studies, the elasticity is estimated only during ventricular diast ole. However, the viscous characteristics of the smooth muscle in the media of the arterial wall are also included in the strain measured during diast ole. Alternatively, during Systole, the smooth muscle has an almost purely elastic characteristic. However, the IVUS probe moves greatly due to the ar rival of the pulsatile wave at the beginning of the ejection period. Theref ore, in this paper, we propose a method to compensate for the movement of t he IVUS probe in order to precisely measure the regional change in thicknes s of the arterial wall during one cardiac cycle. Basic experiments using a silicone rubber tube, in which pulsatile flow is generated by an artificial heart, determined the two-dimensional (2-D) distribution of the regional c hange in thickness and the elasticity. The obtained incremental elastic mod ulus coincides with that determined by the static pressure-train test. Furt hermore, in an in vitro experiment performed on an extracted human iliac ar tery, the 2-D distribution of elasticity is obtained and compared with path ological results.