An example of ex vivo aortic autoradiographic (ARG) analysis. (A) HE staining of a 20-μm cryosection, showing the aortic arch and branches of arteries (B) autoradiograph (grayscale) from section (A) superimposed with the patch image made from the HE-stained section (A). (C) Autoradiograph superimposed with contour image and an example of ROI analysis: R2 and R4, plaque; R1 and R3, healthy vessel wall; R5 and R6, adventitia. (D) Panel shows the ARG results of section (C). Results are expressed as PSL/mm2 (mean ± SD), normalized against the internal control tissue (muscle). In this representative section, the plaque/wall ratio is 1.6 and plaque/adventitia ratio 1.1, whereas in the whole study population, the corresponding ratios were 1.8 ± 0.2 and 1.3 ± 0.2.