Fasted and fed small bowel motility patterns at cine-MRI in chronic intestinal pseudo-obstruction

Abstract

Background: Chronic intestinal pseudo-obstruction (CIPO) is a severe intestinal motility disorder of which the pathophysiology is largely unknown. This study aimed at gaining insight in fasted and fed small bowel motility in CIPO patients using cine-MRI with caloric stimulation.

Methods: Eight adult patients with manometrically confirmed CIPO were prospectively included. Patients underwent a cine-MRI protocol after an overnight fast, comprising fasting-state scans and scans after ingestion of a meal (Nutridrink, 300 kcal). Small bowel motility was quantified resulting in a motility score in arbitrary units (AU) and visually assessed by three radiologists. Findings were compared with those in 16 healthy volunteers.

Key results: Motility scores (median, IQR) in CIPO patients were 0.21 (0.15-0.30) in the fasting state and 0.23 (0.15-0.27) directly postprandially. In healthy volunteers, corresponding motility scores were 0.15 (0.13-0.18) and 0.22 (0.19-0.25), respectively. The postprandial change in motility score was +1% (-19 to +21%) in CIPO and +39% (+23 to +50%) in healthy volunteers (p = 0.001*). Visual analysis revealed increased small bowel contractility in four, normal in two, and decreased in two CIPO patients.

Conclusions & inferences: Surprisingly, we found hyperactive small bowel motility in half of the CIPO patients, suggestive of uncoordinated motility. A wide variation in motility patterns was observed, both higher, lower, and comparable contractility compared with healthy subjects. No clear postprandial activation was seen in patients. Cine-MRI helps to gain insight in this complex disease and can potentially impact treatment decisions in the future.

Keywords: cine magnetic resonance imaging; food challenge; gastrointestinal motility; intestinal pseudo-obstruction; magnetic resonance imaging; small intestine.

FIGURE 1

Edge detection method. A, shows a reference image of a cine‐MRI scan on which the region of interest, the small bowel, is delineated. Within this region of interest edge detection is applied, resulting in the edge detection map (B), all black areas in this map are excluded from the calculation of the motility score. The motility score is calculated from the final motility map (C), with areas of high motility in red and low motility in blue.

FIGURE 2

Quantified global small bowel motility. Every line represents the motility scores of an individual CIPO patient at two fasted time points and three postprandial time points. The orange dashed line represents the median motility score in healthy volunteers (interquartile range in gray)

FIGURE 3

Effect of the test meal on small bowel motility. Dot plot (A) representing change between baseline motility and direct postprandial motility, p = 0.001* and (B) representing change between baseline motility and 20 minutes postprandial motility, p = 0.004*. The horizontal lines represent the median.

FIGURE 4

Maximal luminal diameter per patient. Small bowel luminal diameter at four time points per patient (A–H) is shown. The dashed line at 3 cm represents the upper limit of normal small bowel luminal diameter; above this line is interpreted as distension.

FIGURE 5

Quantified and visually assessed small bowel motility per CIPO patient. For patients A–H, a MRI slice is shown and graphs with quantified and visual motility assessment at four time points. The left graph shows the quantified motility scores and the orange dashed line represents the median motility in healthy volunteers with the interquartile range in gray. The right graph shows the visually assessed small bowel motility, with the upwards arrow on the y‐axis representing increased motility and vice versa.