A Proposed Ordinal Scale for Grading Histology in Elastase-Induced, Saccular Aneurysms

Photomicrographs illustrating dome healing. All sections were stained with H&E.

A, Representative section (magnification ×20) of a dome score = 0, showing that the aneurysm cavity is completely filled with unorganized thrombus.

B, Representative section (magnification ×15) when the dome score = 1, where less than one third of aneurysm cavity is filled with organized tissue.

C, Representative section (magnification ×20) with dome score = 2, in that approximately one half of the aneurysm cavity is filled with organized tissue.

D, Representative section (magnification ×15) with a dome score = 3, most the aneurysm cavity filled with organized tissue; a residual small area of unorganized thrombus is also evident.

E, Representative section (magnification ×15) with the dome score = 4, showing the aneurysm cavity to be entirely filled with loose organized tissue.

F, Representative section (magnification ×40) with the dome score = 5. Staining in this section reveals the aneurysm cavity is completely filled with attenuated cellular tissue.

Photomicrographs illustrating histologic coil compaction scoring. All sections were stained with H&E.

A, Representative section for neck compaction score = 3, showing the tissue across the aneurysm neck is convex to the aneurysm cavity (magnification ×20).

B, Representative section for a neck compaction score = 2, showing the tissue at the neck is flat (magnification ×60).

C, Representative section for a neck compaction score = 1, showing the tissue at the neck slightly concave to the aneurysm cavity (magnification ×15).

D, Representative section for a neck compaction score = 0, showing the tissue at the interface between the aneurysm cavity and parent artery is markedly concave to the aneurysm cavity (magnification ×15).

Mean and SD for scoring categories, in addition to Total Score, over survival time in weeks. Different colored bars represent the mean ± SD for each variable in the ordinal scale at 2 weeks (n = 5), 4 weeks (n = 8), 10 weeks (n = 5), 16 weeks (n = 6), and 24 weeks (n = 6). Values for 2 weeks are significantly less (P < .05) than for 4 weeks, 16 weeks, and 24 weeks. Ten-week values are significantly less (P < .05) than 24-week values.