Background: IBD specialists often find it difficult to make treatment plans for Crohn's disease (CD) patients, due to both inflammatory and fibrotic components of diseased bowel segments. It is essential to estimate the extent, dominance, depth and overall clinical implications of these. We have preliminarily evaluated a novel imaging method, FDG-PET MRenterography (PET-MRe) and its correlation with the commonly used biomarkers.
Methods: In this exploratory study, 41 patients who were referred for colonoscopy for suspicion of CD, or evaluation of active CD, with a known prior diagnosis, underwent PET-MRe within 8 weeks of the endoscopic evaluation. A SES-CD was obtained at colonoscopy, CRP and fecal calprotectin (FC) were also measured. Imaging results were divided into: no, short-segment (<10cm) or long-segmental (>10cm) inflammation. The study was approved by the local IRB. Correlations were made between the extent of inflammation obtained by PET-MRe and the other parameters using the SAS 9.4 system, by Chi-Square and Wilcoxon tests. Univariate and multivariate analyses were performed per the above parameters.
Results: 34 patients had terminal ileal (TI) disease and 7 had no evidence of inflammation. There was good correlation between active inflammation demonstrated in the terminal ileum by PET-MRe and FC >150, p<0.0008. Increased CRP levels and SES-CD score, showed a trend correlating with the extent of inflammation obtained from imaging, with median values of 0.69, 0.76 and 1.35 for CRP (p=0.26), and SES-CD scores of 1, 4.5 and 5.5 (p=0.32), when compared to non-inflamed, short segment and long segment of inflamed terminal ileum, respectively.
Conclusions: This is a preliminary report of our pilot cohort of CD patients assessed by a novel imaging technique which will further enable the 3-dimensional evaluation of the burden of inflammation in CD patients. The transmural nature of this disease necessitates a modality that incorporates deep tissues uptake of FDG. We intend to further investigate the composite score that will express this.