P0089 Infra-red microspectroscopy provides quantitative assessment of fibro-inflammation in Crohn’s disease strictures and predicts post-operative recurrence
Authors: Keung C , Pawlowski R , Ryan A , Kwan E , Longano A , Lim R , Sievert W , Moore G T , Wood B 
Published: January 2025

Abstract

Background
Quantitative assessment of fibro-inflammation in Crohn’s disease strictures remains a challenge despite its role in clinical decision making using immunomodulatory drugs or endoscopic/surgical interventions. While histology remains the gold standard, no validated histological scoring systems for Crohn’s disease strictures exist and assessment is subject to significant intra- and inter-observer variability. Fourier-transform infra-red (FTIR) microspectroscopy is a reproducible, label-free and non-destructive approach for analysing tissue biochemistry via molecular vibrations. We have previously shown accurate assessment of inflammation severity using this technique in colitis models (1). The aim of this study was to assess Crohn’s disease strictures using FTIR spectroscopy and to evaluate if tissue spectra can predict post-operative Crohn’s disease recurrence.

Methods
Full-thickness Crohn’s stricture resections (n=72) were obtained in paraffin and sectioned for hyperspectral imaging using the Agilent Cary 670 FPA-IR coupled with the Agilent Cary 620 microscope in transflection mode in the wavenumber region 1800–800 cm-1. Nearly 8 million spectra in total were acquired from regions of interest in each of the bowel wall layers per sample (Figure 1). Spectra was transformed to the second derivative, normalised and reduced to 25 spectra per sample prior to analysis using partial least squares discriminant analysis (PLSDA) with internal cross-validation. Adjacent tissue sections were stained with H&E, Masson’s trichrome and α-smooth muscle actin. Histology was scored based on the averaged scores of three independent clinical histopathologists for inflammation, fibrosis and muscular changes.

Results
Tissue infra-red spectra demonstrated excellent performance defined by area under the receiver operating characteristic curve (AUC) of ≥0.9 using PLSDA to classify severe from mild inflammation and good (AUC ≥0.8) to excellent (AUC ≥0.9) performance to classify severe from mild fibrosis and muscular hyperplasia/hypertrophy. In those with complete macroscopic Crohn’s disease resection (n=51), spectra from index stricture resections demonstrated good performance (AUC ≥0.8) in discriminating between future significant endoscopic recurrence defined by Rutgeert’s score ≥ i2 (2) and excellent performance for surgical recurrence (AUC ≥0.9) defined as future surgical resection of Crohn’s recurrence.

Conclusion
FTIR microspectroscopy can detect biochemical differences underlying inflammation, fibrosis and muscular changes in Crohn’s strictures and provide simultaneous quantitative assessment. The biochemical tissue fingerprints demonstrate good to excellent discrimination for predicting endoscopic and surgical Crohn’s recurrence, respectively.

References
1. Keung C, Heraud P, Kuk N, Lim R, Sievert W, Moore G, et al. Fourier-Transform Infra-Red Microspectroscopy Can Accurately Diagnose Colitis and Assess Severity of Inflammation. Int J Mol Sci. 2022;23(5).
2. Rutgeerts P, Geboes K, Vantrappen G, Beyls J, Kerremans R, Hiele M. Predictability of the postoperative course of Crohn's disease. Gastroenterology. 1990;99(4):956-63.