Fig. 2

Adjustable geometric models of the cross-section of a PAS, where the circle represents the outer boundary of the artery and the ellipse represents the outer boundary of the PAS. The circle and ellipse may be either a concentric or b non-concentric. In a, the geometry is parameterized by the circle radius \(r_1\) and the two axes of the ellipse \(r_2\) and \(r_3\). In b, there are two additional parameters: eccentricities c along the x-direction and d along the y-direction