Abstract 548: Variations in Venous Wall Strain Can Be Modeled and Measured Using IVUS-Derived Elastography

Objectives: Iliofemoral venous outflow stenting has been used to treat both acute and chronic venous thrombosis. It may be beneficial to understand the properties of the normal venous wall and the flow through collapsible tubes to develop new stent technology and improve long-term patency. We hypothesize that radial and circumferential strain can be modeled and measured using intravascular ultrasound (IVUS) techniques to describe venous geometry and asymmetric vessel wall characteristics. Methods: A hydrogel phantom was used to mimic the mechanical properties of a homogeneous vein, including geometry and wall compliance. Radio-frequency (RF) echo frames were acquired using a modified IVUS system with an 8.5 Mhz catheter. All RF signals were digitized to 14 bits at 50 MHz. Radial strain was estimated by applying an intensity matching, image registration based algorithm to the digitized frames. Results: The radial strain images (Figure 1) show increasing positive strain (radial wall thickening) on the top and bottom of the phantom with decreasing negative values (radial wall thinning) at either side. Results suggest an asymmetric compression pattern typical of a vessel collapsing under negative pressure. Conclusions: In conclusion, our data suggest that novel strain analysis can be performed on a phantom vessel consistent with the mechanical properties of the venous system. Further work with venous elastography will help define the mechanical properties of the venous wall and facilitate the development of new stent technology to treat venous disease.