Evaluation of pan-alimentary MRI examinations: intrasubject variability and examination duration

Many gastrointestinal (GI) disorders entail disturbances in GI functions such as motility and volume. Magnetic resonance imaging (MRI) can assess GI motility and volumes in one single examination; however, challenges with clinical implementation with pan-alimentary MRI can be intrasubject variability and time-consuming examinations.

This study aims to examine 1) intrasubject variability in MRI-assessed gut volumes, motility and whole-gut transit time 2) propose a shortened pan-alimentary MRI examination, and 3) demonstrate feasibility of clinical implementation of pan-alimentary MRI.

Five individual MRI studies were included in this study. The intrasubject variability of MRI measurements was assessed in 40 healthy subjects scanned twice with more than two weeks between examinations. Parameters were assessed with the intraclass correlation coefficient (ICC) and included gastric half-emptying time, small bowel motility index, whole gut transit capsule score, and segmental volumes of stomach, small bowel and colon. A shortened MRI examination was tested using estimations of gastric half-emptying time calculated using either a five datapoint- and a three datapoint postprandial MRI examination, performed in 86 individuals. Feasibility of clinical implementation was exemplified by two patient cases.

Gastric half-emptying time showed moderate reproducibility (ICC: 0.53 [95% CI: 0.31-0.74]). Fasting small bowel motility index had an ICC of 0.66 [0.45-0.82], and fasting total colon volume had an ICC of 0.47 [0.23-0.72]. Whole gut transit capsule scores had poor reproducibility (ICC: 0.27 [0.04-0.76]). Reducing scan datapoints for calculating gastric half-emptying time, maintained accuracy (concordance correlation coefficient: 0.93-0.95). Feasibility of implementation was shown by successful examinations at both a minor- and a university hospital.

Despite fluctuating ICCs of intrasubject variation measurements, physiological variances are to be expected when assessing the GI tract. The proposed shortened MRI examination is applicable outside specialized research settings and may provide new insights in patients with motility disorders.