Feasibility Study of a New Magnetic Resonance Imaging Mini-capsule Device to Measure Whole Gut Transit Time in Paediatric Constipation

Abstract

Objective: In England, 27,500 children are referred annually to hospital with constipation. An objective measure of whole gut transit time (WGTT) could aid management. The current standard WGTT assessment, the x-ray radiopaque marker (ROM) test, gives poor definition of colonic anatomy and the radiation dose required is undesirable in children. Our objective was to develop an alternative magnetic resonance imaging (MRI) WGTT measure to the x-ray ROM test and to demonstrate its initial feasibility in paediatric constipation.

Methods: With the Nottingham Young Person's Advisory Group we developed a small (8 × 4 mm), inert polypropylene capsule shell filled with MRI-visible fat emulsion. The capsule can be imaged using MRI fat and water in-phase and out-of-phase imaging. Sixteen patients with constipation and 19 healthy participants aged 7 to 18 years old were recruited. Following a common ROM protocol, the participants swallowed 24 mini-capsules each day for 3 days and were imaged on days 4 and 7 using MRI. The number of successful studies (feasibility) and WGTT were assessed. Participants' EuroQoL Visual Analogue Scale were also collected and compared between the day before the taking the first set of mini-capsules to the day after the last MRI study day.

Results: The mini-capsules were imaged successfully in the colon of all participants. The WGTT was 78 ± 35 hours (mean ± standard deviation) for patients, and 36 ± 16 hours, P < 0.0001 for healthy controls. Carrying out the procedures did not change the EuroQoL Visual Analogue Scale scores before and after the procedures.

Conclusions: Magnetic Resonance Imaging in Paediatric Constipation was a first-in-child feasibility study of a new medical device to measure WGTT in paediatric constipation using MRI. The study showed that the new method is feasible and is well tolerated.

FIGURE 1

CONSORT diagram for the study. WGTT = whole gut transit time.

FIGURE 2

Mini-capsule MRI device markers pictured near a 20 pence coin (21 mm in diameter) for size comparison.

FIGURE 3

A, A coronal, derived in-phase minus out-of-phase magnetic resonance imaging (MRI) image of a 7-year-old patient participant, showing in the sigmoid/rectum 6 mini-capsules with positive signal against the chime. The mini-capsules are indicated by the white arrows in the corresponding expanded area on the right hand side. B, An axial, derived in-phase minus out-of-phase MRI image of the same patient participant, showing in the descending colon 2 mini-capsules with positive signal against the chyme. The mini-capsules are indicated by the white arrows in the corresponding expanded area on the right hand side.

FIGURE 4

Whole gut transit time (mean and standard deviation) for young patients with constipation (n = 16) and healthy controls (n = 19). ^∗P < 0.0001.