Inter- and intra-observer variability of software quantified bowel motility measurements of small bowel Crohn's disease: findings from the MOTILITY trial.

OBJECTIVES

Motility magnetic resonance imaging (mMRI) is a potential marker of disease activity of small bowel Crohn's disease (SBCD), but there is limited data on its reproducibility. We assessed inter- and intra-observer agreement of small bowel motility as part of a prospective multicentre trial investigating whether mMRI can predict longer-term response to biologic therapy in active, non-stricturing SB-CD (MOTILITY Trial).

METHODS

297 segmental small bowel motility scores from 104 SBCD patients (mean age 38.9 years, 43 female) recruited to the MOTILITY trial were measured independently by two radiologists experienced in mMRI, using GIQuant software. Twenty-six datasets were re-read by both radiologists to test intra-observer variability after a washout period of at least 6 weeks. Five gastrointestinal radiologists inexperienced in mMRI derived 66 segmental motility scores from the same 30 randomly selected patients. Agreement was quantified using the intra-class correlation coefficient (ICC).

RESULTS

There was moderate agreement for mMRI-derived segmental small bowel motility measurements for both mMRI-experienced and inexperienced radiologists (ICC 0.59 (95% CI: 0.51, 0.66) and 0.70 (95% CI: 0.61, 0.78), respectively). Agreement remained moderate to good, combining the experienced trial MRI reader measurements with those of the five inexperienced radiologists (ICC 0.69 (95% CI: 0.61, 0.78). Intra-observer agreement for the two mMRI experienced radiologists was (0.71 (95% CI: 0.44, 0.86) and 0.70 (95% CI: 0.44, 0.86)).

CONCLUSIONS

There is moderate to good interobserver agreement for mMRI measurements of segmental small bowel motility for both experienced and inexperienced radiologists.

CRITICAL RELEVANCE STATEMENT

Study findings support the continuing clinical translation of motility MRI as a reproducible biomarker of disease activity and treatment response in Crohn's disease.

KEY POINTS

Motility MRI is a novel biomarker of small bowel Crohn's disease activity. Currently, limited data on intra- and inter-observer variability exists. Motility MRI shows moderate to good inter- and intra-observer agreement. Intraclass correlation was 0.59-0.71 for experienced and inexperienced radiologists. Motility MRI is reproducible, supporting its utility as a biomarker of disease activity.