Open Access Study protocol

METRIC (MREnterography or ulTRasound in Crohn’s disease): a study protocol for a multicentre, non-randomised, single-arm, prospective comparison study of magnetic resonance enterography and small bowel ultrasound compared to a reference standard in those aged 16 and over

Stuart Taylor1*, Susan Mallett2, Gauraang Bhatnagar1, Stuart Bloom3, Arun Gupta4, Steve Halligan1, John Hamlin5, Ailsa Hart6, Antony Higginson7, Ilan Jacobs8, Sara McCartney3, Steve Morris9, Nicola Muirhead10, Charles Murray11, Shonit Punwani1, Manuel Rodriguez-Justo12, Andrew Slater13, Simon Travis14, Damian Tolan15, Alastair Windsor16, Peter Wylie17 and Ian Zealley18

Author Affiliations

1 Center for Medical Imaging, University College London, 250 Euston Rd, London NW1 2PG, UK

2 Medical Statistics, Department of Primary Health Care Sciences, University of Oxford, 2nd Floor Offices, 23-38 Hythe Bridge Street, Oxford, UK

3 Department of Gastroenterology, University College London Hospital, 235 Euston Road, London, UK

4 Intestinal Imaging, St Marks Hospital,Harrow Road, London, UK

5 Gastroenterology,Leeds Teaching Hospitals NHS Trust, St James’s University Hospital, Beckett Street, Leeds, UK

6 Gastroenterology, St Marks Hospital, Harrow Road, London, UK

7 Medical Imaging, Queen Alexandra Hospital, Southwick Hill Road, Cosham, UK

8 Public representative, Patient forum, National Association of Crohn’s and colitis, c/oUCL Partners CTU, Maple House, 149 Tottenham Court Rd, London, UK

9 Health Economics, UCL Research Department of Epidemiology and Public Health, University College London, 1-19 Torrington Place, London, UK

10 UCL Clinical Trials Unit, UCL Gower Street, London, UK

11 Gastroenterology, Royal Free Hospital, Pond Street, London, UK

12 Department of Gastrointestinal Pathology, University College London Hospital, 235 Euston Road, London, UK

13 Medical Imaging, Oxford University Hospitals NHS Trust, Oxford, OX3 9DU, UK

14 Translational Gastroenterology Unit, Oxford University Hospitals NHS Trust, Oxford, OX3 9DU, UK

15 Clinical Radiology, Leeds Teaching Hospitals NHS Trust, St James’s University Hospital, Beckett Street, Leeds, UK

16 Department of Surgery, University College London Hospital, 235 Euston Road, London, UK

17 Imaging, Royal Free Hospital, Pond Street, London, UK

18 Medical Imaging, Ninewells Hospital, Dundee, UK

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BMC Gastroenterology 2014, 14:142  doi:10.1186/1471-230X-14-142

Published: 11 August 2014

Abstract

Background

Crohn’s disease (CD) is a lifelong, relapsing and remitting inflammatory condition of the intestine. Medical imaging is crucial for diagnosis, phenotyping, activity assessment and detecting complications. Diverse small bowel imaging tests are available but a standard algorithm for deployment is lacking. Many hospitals employ tests that impart ionising radiation, of particular concern to this young patient population. Magnetic resonance enterography (MRE) and small bowel ultrasound (USS) are attractive options, as they do not use ionising radiation. However, their comparative diagnostic accuracy has not been compared in large head to head trials. METRIC aims to compare the diagnostic efficacy, therapeutic impact and cost effectiveness of MRE and USS in newly diagnosed and relapsing CD.

Methods

METRIC (ISRCTN03982913) is a multicentre, non-randomised, single-arm, prospective comparison study. Two patient cohorts will be recruited; those newly diagnosed with CD, and those with suspected relapse. Both will undergo MRE and USS in addition to other imaging tests performed as part of clinical care. Strict blinding protocols will be enforced for those interpreting MRE and USS. The Harvey Bradshaw index, C-reactive protein and faecal calprotectin will be collected at recruitment and 3 months, and patient experience will be assessed via questionnaires. A multidisciplinary consensus panel will assess all available clinical and imaging data up to 6 months after recruitment of each patient and will define the standard of reference for the presence, localisation and activity of disease against which the diagnostic accuracy of MRE and USS will be judged. Diagnostic impact of MRE and USS will be evaluated and cost effectiveness will be assessed. The primary outcome measure is the difference in per patient sensitivity between MRE and USS for the correct identification and localisation of small bowel CD.

Discussion

The trial is open at 5 centres with 46 patients recruited. We highlight the importance of stringent blinding protocols in order to delineate the true diagnostic accuracy of both imaging tests and discuss the difficulties of diagnostic accuracy studies in the absence of a single standard of reference, describing our approach utilising a consensus panel whilst minimising incorporation bias.

Trial registration

METRIC - ISRCTN03982913 – 05.11.13.

Keywords:
Crohn’s disease; Inflammatory bowel disease; MRE; USS; Consensus panel