Quantified terminal ileal motility during MR enterography as a potential biomarker of Crohn's disease activity: a preliminary study

To compare quantified terminal ileal (TI) motility during MR enterography (MRE) with histopathological severity of acute inflammation in Crohn's disease. A total of 28 Crohn's patients underwent MRE and endoscopic TI biopsy. Axial and coronal TrueFISP, HASTE and post-gadolinium VIBE images were supplemented by multiple coronal TrueFISP cine motility sequences through the small bowel volume. TI motility index (MI) was quantified using validated software; an acute inflammation score (eAIS; 0-6) was assigned to the biopsy. Two observers qualitatively scored mural thickness, T2 signal, contrast enhancement and perimural oedema (0-3) to produce an activity score (aMRIs) based on anatomical MRI. The association among the MI, eAIS and aMRIs was tested using Spearman's rank correlation. Wilcoxon rank sum test compared motility in subjects with and without histopathological inflammation. Mean MI and mean eAIS were 0.27 (range 0.06-0.55) and 1.5 (range 0-5), respectively. There was a significant difference in MI between non-inflamed (mean 0.37, range 0.13-0.55) and inflamed (mean 0.19, range 0.06-0.44) TI, P = 0.002, and a significant negative correlation between MI and both eAIS (Rho = -0.52, P = 0.005) and aMRIs (R = -0.7, P < 0.001). Quantified TI motility negatively correlates with histopathological measures of disease activity and existing anatomical MRI activity biomarkers. (orig.)