Fig. 2

Schematic vessel boundaries marked as black lines in panel (a) and (b). Lines connecting nearest neighbours of points on the first boundary (panel a left) or the second boundary (panel a right) are drawn as blue lines. Common orthogonals between the two curves of the outer vessel boundaries are marked with red lines and points in panel (b). Choosing the boundary assignment for each segment between inflection points of the vessel separately leads to a set of non-crossing orthogonal line segments. In the right subfigure, the red dashed line shows the medial axis of the vessel computed from these non-crossing orthogonals. The microscopic photograph of the analysed aortic artery with highlighted boundaries is shown in panel (c). The ROI used for normalization is marked in red. (AA = aortic arch, DA = descending aorta, BA = brachycephalic artery, CCA = common carotid artery, SA = subclavian artery). Panel d shows the Cy5.5-AF443 fluorescence image where the manually defined boundary points are marked in white. Natural cubic spline curve interpolation of the boundary points leads to vessel boundaries marked in bold black. The light black line shows the medial axis of the vessel. The unwarped aortic vessel is shown in panel (e), numbers indicate corresponding vessel parts in panel (f) and (g). Panel f depicts the map resulting from standardization, whereas panel g shows additional normalisation