Figure 3
From: Factors that affect mass transport from drug eluting stents into the artery wall
Determination of tortuosity through a porous material using the arc-chord ratio. The tortuosity of a path through a porous structure (A) can be determined by the ratio of the pore length, L, to the displacement, X. As can be seen in (B) and (C), the magnitude of L remains constant but as the compression increases the displacement X reduces to X' which results in an increase in tortuosity.