Introduction
Growing evidence points to appendectomy as an alternative treatment for ulcerative colitis (UC). Histopathological appendiceal inflammation might be correlated with response to appendectomy. Intestinal ultrasound (IUS) is a non-invasive diagnostic modality used to visualize appendiceal inflammation.
Aims & Methods
We aimed to investigate appendiceal IUS’s relationship with histopathology findings in appendix resection specimens. Therapy-refractory UC patients undergoing appendectomy in single center clinical trials were included. IUS parameters included appendix diameter, wall thickness, submucosal layer thickness and submucosal hyperechogenicity. Submucosal layer hyperechogenicity was quantified using the mean aerial grayscale intensity which is a numerical scale 0-255, with zero corresponding to black. To adjust for variations in depth and gain, we measured the ∆ grayscale intensity using the difference between the submucosa and muscularis propria in a perpendicular fashion. The Robarts Histopathology Index (RHI) was used to measure mucosal histological disease activity in the appendix ranging from 0-33. Appendiceal inflammation was defined as RHI >3, with at least subscores of lamina propria neutrophils or epithelium neutrophils ≥1, or presence of ulcers or erosions.
Results
37 of 55 (67.3%) included patients had a visualized appendix on IUS. The median RHI was 6 (IQR 0-12) and histopathological appendiceal inflammation was present in 21/37 (57%). Submucosal layer thickness was significantly higher, and the submucosal layer hyperechogenicity was significantly enhanced in microscopically inflamed appendices (Table 1). Submucosal hyperechogenicity predicted histopathological appendiceal inflammation (OR 1.03, 95% CI 1.0-1.05; p=0.035). Submucosal thickness ≥0.75 mm diagnosed histopathological appendiceal inflammation with 66.7% sensitivity, 81.3% specificity and an AUC of 0.69 (p=0.046). Submucosal hyperechogenicity >110.20 diagnosed histopathological appendiceal inflammation with 57.1% sensitivity, 81.3% specificity and an AUC of 0.69 (p=0.046).
| Table 1. Ultrasound characteristics of the visible appendices |
| IUS characteristic | Total
N=37 | RHI≤3
N=16 | RHI>3
N=21 | p-value |
| Diameter (mm) | 4.3 (3.7-5.8) | 4.3 (3.5-5.6) | 4.4 (3.9-6.0) | 0.24 |
| Wall thickness (mm) | 1.9 (1.5-2.3) | 1.9 (1.4-2.1) | 1.9 (1.5-2.4) | 0.36 |
| Mucosa (mm) | 0.6 (0.4-0.8) | 0.7 (0.4-0.8) | 0.6 (0.4-0.8) | 0.72 |
| Submucosa (mm) | 0.7 (0.5-0.9) | 0.6 (0.4-0.7) | 0.9 (0.6-1.0) | 0.04 |
| Muscularis propria (mm) | 0.5 (0.3-0.6) | 0.5 (0.3-0.6) | 0.5 (0.3-0.7) | 0.5 |
| Submucosal hyperechogenicity (∆ grayscale value, 0-255) | 99.5 (83.4-133.3) | 95.4 (76.2-108.1) | 113.5 (87.7-151.7) | 0.02 |
Conclusion
IUS is able to identify patients with histopathological appendiceal inflammation who may benefit from appendectomy as treatment for UC.
Disclosure
MP received speakers fees from Janssen and Tillotts
EV has nothing to disclose
FV received speaker or honoraria fees from AbbVie, Janssen and Tillotts
MR has nothing to disclose
WB has nothing to disclose
GD has served as a consultant and/or received speaker’s fees from AbbVie, Alimentiv, AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Celltrion Healthcare, Cytoki Pharma, Eli Lilly, Ferring, Galapagos, Glaxo SmithKline, Gossamer Bio, Immunic, InDex Pharmaceuticals, Janssen, Johnson & Johnson, Kaleido, Pfizer, Progenity, Prometheus Biosciences, Prometheus Laboratories, Protagonist Therapeutics, Takeda, Tillotts, Ventyx Biosciences.
AM has nothing to disclose
CB has nothing to disclose
KG has received grants from Pfizer Inc, Celltrion and Galapagos; consultancy fees from AbbVie, Arena Pharmaceuticals, Galapagos, Gilead, Immunic Therapeutics, Janssen Pharmaceuticals, Novartis, Pfizer Inc., Samsung Bioepis and Takeda and speaker’s honoraria from Abbvie, Celltrion, Ferring, Janssen Pharmaceuticals, Novartis, Pfizer Inc, Samsung Bioepis, Takeda and Tillotts.
