Background: The transitory nonuniform expansion, the so-called dogboning, of stent/balloon system is one of the main reasons to induce the acute vascular injury at the two edges of a stent. This kind of vascular injury has a close relationship with the in-stent restenosis. Methods: An experimental model using a silicon tube was performed on three 3.0��23 mm Cypher select stents. In our experimental, straight and curved(curvature 0.385 cm-1 (radius 2.6 cm) and 0.25 cm-1 (radius 2cm)) models made of silicon tube(inner diameter of 3 mm) were used. Stent were implanted at the inflation pressure of 10 atm, and the pressure was subsequently increased to 16 and 20 atm. Dogboning of stent was defined as (distal diameter-central diameter)/central diameter �� 100%. Angiographic 2D analysis and IVUS analysis were performed. Angiographic analysis was performed twice and averaged. Quantitative IVUS measurements were performed at 9 cross sections: three 1mm interval central site and 3 proximal and distal site and averaged. Results: In the straight model, dogboning was lower in high pressure model(10 atm: 4.7% vs 20atm: 2.2% by 2D QCA, 10 atm 2.33% vs 20atm 1.73% by IVUS). In cyper stent , %dogboning was higher in the curved model than straight model at the pressure of 10 atm (straight: 4.7% vs curvature 0.25 cm-1: 7.96% by 2D QCA, straight: 2.33% vs curved: 3.02% by IVUS) and 20 atm(straight 2.2% vs curved 1.14% by 2D QCA, straight: 1.73% vs benging: 1.93% by IVUS). Modeling results showed that the dogboning phenomenon was aggravated by increasing curvature and releaved by increasing inflation pressure. Conclusions: Nonuniform expansion of stent(dogboning) was observed more in curved model and was less in high pressure medel.