The challenge of segmental small bowel motility quantitation using MR enterography

Area of Science:

• Gastrointestinal Imaging
• Medical Physics
• Physiology

Background:

• Dynamic "cine" MRI is increasingly used to assess small bowel motility.
• Quantifying small bowel motility variation in healthy subjects is crucial but poorly described.
• Understanding baseline motility is essential for interpreting disease-related changes.

Purpose of the Study:

• To analyze "cine" MRI for quantifying small bowel motility in healthy individuals.
• To describe within- and between-scan variations in small bowel motility.
• To establish baseline motility values for healthy subjects.

Main Methods:

• MR enterography was performed on 20 healthy adults on two separate occasions.
• Dynamic motility scans were acquired during both breath-hold (BH) and free-breathing (FB) conditions.
• Quantitative motility assessment included contractions per minute (CPM) and Jacobian standard deviation (SD) using four regions of interest (ROIs) per subject.

Main Results:

• Significant within-scan segmental variation was observed for both BH and FB motility metrics (Jacobian SD: p=0.027 for BH, p=0.030 for FB).
• Repeatability analysis showed wide Bland-Altman limits of agreement (LoA) for both CPM and Jacobian SD in BH and FB conditions.
• For example, BH CPM LoA was ±8.36 contractions, and Jacobian SD LoA was ±0.33.

Conclusions:

• MRI-quantified small bowel motility in healthy subjects exhibits considerable intersegmental variation.
• The repeatability of small bowel motility measurements over time is relatively poor.
• This study provides essential baseline data on small bowel motility variability in healthy individuals.