2.2. FLIM database

The database consists of FLIM images of 80 artery segments (from 23 subjects) with their corresponding histological sections stained with CD68 for labeling macrophages (246 histological sections in total). The artery segments were obtained from subjects that not necessarily died from atherosclerosis. The histology sections were cut from specific points previously inked on the right side of the artery lumen, in order to match the histology and the FLIM images (Fig. 1A). The top edge of the artery was also inked and a small notch was made at the bottom to help find the correct orientation. Each dot corresponds to a specific row index in the FLIM image (magenta line in Fig. 1B), which is linked to a corresponding CD68 stained immunohistological section (Fig. 1C).

Artery inking procedure and the correlation to the FLIM images.

(A) Photograph of a sample artery segment with the inked dots at the right side; the inked top edge and the bottom notch were used for orientation; the red dotted line indicates the approximate location of one of the tissue sections cut for histology. (B) Lifetime map (0 – 10 ns) of the 494 ± 20.5 nm channel with a magenta line indicating the correspondence of the row index with the first inked dot on the artery. (C) CD68 stained immunohistological section corresponding to the first inked dot and a graphic representation of the histology-based classification vector derived from lumen classification marks.