Fig. 3.

Extraction of a representative region of medial tissue from a 3D confocal image of the fixed artery. The arterial geometry on the left shows the cylindrical coordinate system relative to the artery of an example location for tissue extraction. The medial block on the right shows how the cylindrical coordinates of the artery are represented relative to the tissue block. ${\mathbf{e}}_{\mathbf{r}}\text{,}{\mathbf{e}}_{\mathit{\theta }}$ and ${\mathbf{e}}_{\mathbf{z}}$ are the radial, circumferential and axial directions, respectively.