due to the impact of the COVID19 pandemic on MRI service provision, NHS hospitals were unable to provide the resources to conduct the study

Constipation in children is a common problem. Managing these children is difficult, partly because they do not respond to laxatives and partly because their bowel problem cannot be defined. A "gut transit time" test can add information to help choose the best therapy but this is often not carried out because of the unsuitable radiation dose involved in the current methods such as X-ray. A new Magnetic Resonance Imaging (MRI) method to measure gut transit time using inert mini-capsules, the size of small pine nuts, has recently been developed and successfully trialled during a feasibility study.

This main multicentre study will trial the mini-capsules in 436 paediatric constipation patients.

A fully powered, multi-centre, open label, pragmatic Randomised Controlled Trial (RCT) to test the use of the TransiCap MRI visible capsules to inform treatment selection and whether this leads to a change in rate of "treatment success" at 12 months after diagnosis.

Two study arms will include 436 young patients that present at secondary or tertiary care with constipation.

All participants will receive the TransiCap MRI Visible Capsules and the MRI scans at presentation, but only the participants in the intervention arm will have the results of their scan shared with the standard care team immediately. The intervention arm will therefore receive treatment which is informed by the TransiCap MRI transit time test. The participants in the control arm will instead receive standard care not informed by theTransiCap MRI visible capsules.

The results of the scans will be shared with the standard care team after the patient's follow up of 12 months is complete. All participants will receive the TransiCap MRI visible capsules and the MRI scans

Inclusion Criteria:

Children aged 7 - 18 years old Able to give assent/consent or have a parent/carer able to give informed consent Willing to allow his or her General Practitioner and consultant, if appropriate, to be notified of participation in the clinical investigation.

Children diagnosed with clinical diagnosis of constipation

Exclusion Criteria:

The participant may not enter the clinical investigation if ANY of the following apply:

Female participants who are pregnant, lactating or planning pregnancy during the course of the clinical investigation. This will be self-reported.

Any history of gastrointestinal surgery that could affect gastrointestinal function, such as colectomy or small bowel resection.

Existing ACE procedure before the first MRI scan. Contraindications for MRI scanning i.e. metallic implants, pacemakers, history of metallic foreign body in eye(s) and penetrating eye injury.

Inability to lie flat and relatively still for less than 5 minutes Poor understanding of English language Current diagnosis of COVID 19. The following disease or disorder; Bowel Stricture disease, Crohn's or any difficulty in swallowing (Dysphagia) Hirschsprung disease, congenital anorectal malformations, Paediatric Pseudo-obstruction syndrome

Currently using the following drugs influencing motility:

1. Opioid analgesics (tramadol, morphine, fentanyl, oxycodone, co-codamol and codydramoland)
2. Antispasmodic Buscopan (hyoscine butylbromide, also known as scopolamine butylbromide) Participants who have participated in another research clinical investigation involving an investigational product in the past 12 weeks.

4 or more bowel movements in one week and no episodes of bowel incontinence in one week (if these are reported in the participant's medical notes. Absence of this information should not warrant exclusion)

Upon completion external parties may request access to the data. Access to the data will be reviewed and approved by the data monitoring committee, funder and sponsor.

Upon completion of the study.

to be determined