Magnetic resonance enterography compared with ultrasonography in newly diagnosed and relapsing Crohn’s disease patients: the METRIC diagnostic accuracy study

Abstract

Background Magnetic resonance enterography and enteric ultrasonography are used to image Crohn’s disease patients. Their diagnostic accuracy for presence, extent and activity of enteric Crohn’s disease was compared. Objective To compare diagnostic accuracy, observer variability, acceptability, diagnostic impact and cost-effectiveness of magnetic resonance enterography and ultrasonography in newly diagnosed or relapsing Crohn’s disease. Design Prospective multicentre cohort study. Setting Eight NHS hospitals. Participants Consecutive participants aged ≥ 16 years, newly diagnosed with Crohn’s disease or with established Crohn’s disease and suspected relapse. Interventions Magnetic resonance enterography and ultrasonography. Main outcome measures The primary outcome was per-participant sensitivity difference between magnetic resonance enterography and ultrasonography for small bowel Crohn’s disease extent. Secondary outcomes included sensitivity and specificity for small bowel Crohn’s disease and colonic Crohn’s disease extent, and sensitivity and specificity for small bowel Crohn’s disease and colonic Crohn’s disease presence; identification of active disease; interobserver variation; participant acceptability; diagnostic impact; and cost-effectiveness. Results Out of the 518 participants assessed, 335 entered the trial, with 51 excluded, giving a final cohort of 284 (133 and 151 in new diagnosis and suspected relapse cohorts, respectively). Across the whole cohort, for small bowel Crohn’s disease extent, magnetic resonance enterography sensitivity [80%, 95% confidence interval (CI) 72% to 86%] was significantly greater than ultrasonography sensitivity (70%, 95% CI 62% to 78%), with a 10% difference (95% CI 1% to 18%; p = 0.027). For small bowel Crohn’s disease extent, magnetic resonance enterography specificity (95%, 95% CI 85% to 98%) was significantly greater than ultrasonography specificity (81%, 95% CI 64% to 91%), with a 14% difference (95% CI 1% to 27%). For small bowel Crohn’s disease presence, magnetic resonance enterography sensitivity (97%, 95% CI 91% to 99%) was significantly greater than ultrasonography sensitivity (92%, 95% CI 84% to 96%), with a 5% difference (95% CI 1% to 9%). For small bowel Crohn’s disease presence, magnetic resonance enterography specificity was 96% (95% CI 86% to 99%) and ultrasonography specificity was 84% (95% CI 65% to 94%), with a 12% difference (95% CI 0% to 25%). Test sensitivities for small bowel Crohn’s disease presence and extent were similar in the two cohorts. For colonic Crohn’s disease presence in newly diagnosed participants, ultrasonography sensitivity (67%, 95% CI 49% to 81%) was significantly greater than magnetic resonance enterography sensitivity (47%, 95% CI 31% to 64%), with a 20% difference (95% CI 1% to 39%). For active small bowel Crohn’s disease, magnetic resonance enterography sensitivity (96%, 95% CI 92% to 99%) was significantly greater than ultrasonography sensitivity (90%, 95% CI 82% to 95%), with a 6% difference (95% CI 2% to 11%). There was some disagreement between readers for both tests. A total of 88% of participants rated magnetic resonance enterography as very or fairly acceptable, which is significantly lower than the percentage (99%) of participants who did so for ultrasonography. Therapeutic decisions based on magnetic resonance enterography alone and ultrasonography alone agreed with the final decision in 122 out of 158 (77%) cases and 124 out of 158 (78%) cases, respectively. There were no differences in costs or quality-adjusted life-years between tests. Limitations Magnetic resonance enterography and ultrasonography scans were interpreted by practitioners blinded to clinical data (but not participant cohort), which does not reflect use in clinical practice. Conclusions Magnetic resonance enterography has higher accuracy for detecting the presence, extent and activity of small bowel Crohn’s disease than ultrasonography does. Both tests have variable interobserver agreement and are broadly acceptable to participants, although ultrasonography produces less participant burden. Diagnostic impact and cost-effectiveness are similar. Recommendations for future work include investigation of the comparative utility of magnetic resonance enterography and ultrasonography for treatment response assessment and investigation of non-specific abdominal symptoms to confirm or refute Crohn’s disease. Trial registration Current Controlled Trials ISRCTN03982913. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 42. See the NIHR Journals Library website for further project information.

Observer agreement for small bowel ultrasound in Crohn’s disease: results from the METRIC trial

“…A small proportion of the results (appropriately acknowledged) have been previously published in Health Technology Assessment [17]. The current report represents a more detailed description of the study findings.…”

“… Reproduced with permission from Taylor et al [ 17 ] Contains information licensed under the Non-Commercial Government Licence v2.0 P1 number of positive reads practitioner 1, P2 number of positive reads practitioner 2 a Patient classification by consensus reference standard b Small bowel disease extent—Disease presence and correct location in the small bowel *Both practitioners agree with consensus reference standard …”

“…Reproduced with permission from Taylor et al [ 17 ] Contains information licensed under the Non-Commercial Government Licence v2.0…”

Diagnostic Accuracy of Non-Invasive Imaging for Detection of Colonic Inflammation in Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

“…The diagnostic test values (TP, FP, TN, and FN) of the colonic segments and the sensitivity and specificity values were not presented in all the included studies. The meta-analyses were carried out only in two separate groups, including 13 MRI studies [13,14,17,25,[28][29][30][31][32] and 5 US studies [14,25,32,33], which they had either the calculated TP, FP, TN, and FN or the reported sensitivity and specificity values presented.…”

Imaging Inflammation – From Whole Body Imaging to Cellular Resolution

“…Nevertheless, recent studies advise preferring MR enterography because of the absence of ionizing radiation, a very high soft-tissue contrast, and a lower incidence of adverse events ( 61 ). Although MRI and US are regarded as complementary methods in CD ( 59 ), most studies revealed superior accuracy of MRI for detecting the presence, extent, and activity of small bowel CD disease compared to US ( 62 ). In general, MRI protocol comprises fastening and application of hyperosmolar oral contrast agents like mannitol prior to the examination.…”