Table 3.

Bowel wall median second harmonic imaging microscopy (SHIM) collagen measurements, including by individual bowel wall histological layer, from resected pediatric strictured ileal segments and small bowel surgical margins (n=18)

Histological layer	Median	Interquartile range	P-value*
Entire bowel wall, stricture*	0.17	0.11–0.27	0.007
Stricture – mucosa	0.001	0.0002–0.008	0.57
Stricture – submucosa	0.29	0.09–0.32	0.08
Stricture – muscularis propria, inner (circular) layer	0.15	0.09–0.18	0.37
Stricture – muscularis propria, outer (longitudinal) layer	0.10	0.06–0.12	0.002
Entire bowel wall, surgical margin*	0.14	0.08–0.17
Margin – mucosa	0.001	0.0004–0.003
Margin – submucosa	0.30	0.19–0.35
Margin – muscularis propria, inner (circular) layer	0.12	0.05–0.16
Margin – muscularis propria, outer (longitudinal) layer	0.03	0.02–0.04

^*Stricture versus small bowel surgical margin SHIM collagen measurements (Mann-Whitney U test)

Measurements are dimensionless, as they represent the ratio of collagen signal area to total area (both in μm²)