Magnetic Resonance Imaging of the Small Bowel in Crohn's Disease: A Systematic Review and Meta-Analysis

Predictive value of patency capsule and magnetic resonance enterography for capsule endoscopy retention in patients with established Crohn's disease

INTRODUCTION

retention is the most common adverse event of the small bowel capsule endoscopy procedure. Patency capsule (Medtronic, Dublin, Ireland) and magnetic resonance enterography are two diagnostic methods that can prevent small bowel capsule endoscopy retention. The aim of this study was to evaluate the predictive value of these two diagnostic methods.

MATERIAL AND METHODS

a prospective, comparative and observational study was performed in patients with established Crohn's disease. All patients had undergone magnetic resonance enterography and patency capsule procedures. If the patency capsule was not retained, the patient underwent a small bowel capsule endoscopy; otherwise, double balloon enteroscopy was performed to locate the stenosis. Magnetic resonance enterography predictive criteria for retention were analyzed in all cases. Sensitivity, specificity, positive predictive value and negative predictive value of the patency capsule and magnetic resonance enterography compared to small bowel capsule endoscopy or double balloon enteroscopy were calculated.

RESULTS

forty patients were included (24 female, 55 ± 13 years old). Retention criteria with capsule endoscopy or double balloon enteroscopy were found in six patients, agreeing in five cases with patency capsule and in three cases with magnetic resonance enterography. Sensitivity, specificity, positive predictive value, negative predictive value and Kappa coefficient for predicting retention with the patency capsule were 83 %, 100 %, 100 % and 97 %, respectively, and 50 %, 91 %, 50 % and 91 %, respectively, with magnetic resonance enterography.

CONCLUSIONS

patency capsule has a higher sensitivity and positive predictive value than magnetic resonance enterography for preventing small bowel capsule endoscopy retention in Crohn's disease patients.

Small-bowel capsule endoscopy and device-assisted enteroscopy for diagnosis and treatment of small-bowel disorders: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2022

MR1: ESGE recommends small-bowel capsule endoscopy as the first-line examination, before consideration of other endoscopic and radiological diagnostic tests for suspected small-bowel bleeding, given the excellent safety profile of capsule endoscopy, its patient tolerability, and its potential to visualize the entire small-bowel mucosa.Strong recommendation, moderate quality evidence. MR2: ESGE recommends small-bowel capsule endoscopy in patients with overt suspected small-bowel bleeding as soon as possible after the bleeding episode, ideally within 48 hours, to maximize the diagnostic and subsequent therapeutic yield.Strong recommendation, high quality evidence. MR3: ESGE does not recommend routine second-look endoscopy prior to small-bowel capsule endoscopy in patients with suspected small-bowel bleeding or iron-deficiency anemia.Strong recommendation, low quality evidence. MR4: ESGE recommends conservative management in those patients with suspected small-bowel bleeding and high quality negative small-bowel capsule endoscopy.Strong recommendation, moderate quality evidence. MR5: ESGE recommends device-assisted enteroscopy to confirm and possibly treat lesions identified by small-bowel capsule endoscopy.Strong recommendation, high quality evidence. MR6: ESGE recommends the performance of small-bowel capsule endoscopy as a first-line examination in patients with iron-deficiency anemia when small bowel evaluation is indicated.Strong recommendation, high quality evidence. MR7: ESGE recommends small-bowel capsule endoscopy in patients with suspected Crohn's disease and negative ileocolonoscopy findings as the initial diagnostic modality for investigating the small bowel, in the absence of obstructive symptoms or known bowel stenosis.Strong recommendation, high quality evidence. MR8: ESGE recommends, in patients with unremarkable or nondiagnostic findings from dedicated small-bowel cross-sectional imaging, small-bowel capsule endoscopy as a subsequent investigation if deemed likely to influence patient management.Strong recommendation, low quality evidence. MR9: ESGE recommends, in patients with established Crohn's disease, the use of a patency capsule before small-bowel capsule endoscopy to decrease the capsule retention rate.Strong recommendation, moderate quality evidence. MR10: ESGE recommends device-assisted enteroscopy (DAE) as an alternative to surgery for foreign bodies retained in the small bowel requiring retrieval in patients without acute intestinal obstruction.Strong recommendation, moderate quality evidence. MR11: ESGE recommends DAE-endoscopic retrograde cholangiopancreatography (DAE-ERCP) as a first-line endoscopic approach to treat pancreaticobiliary diseases in patients with surgically altered anatomy (except for Billroth II patients).Strong recommendation, moderate quality evidence.

Comparison of Diagnostic Performance of Ultrasonography and Magnetic Resonance Enterography in the Assessment of Active Bowel Lesions in Patients with Crohn’s Disease: A Systematic Review and Meta-Analysis

We aimed to evaluate and compare the diagnostic performances of ultrasonography (US) and magnetic resonance enterography (MRE) in assessing active bowel lesions in patients with Crohn’s disease (CD). Materials and Methods: We searched PubMed and EMBASE for studies in which US and MRE were used to assess active bowel lesions in CD patients. Bivariate random effect meta-analytic methods were used to estimate pooled sensitivity, specificity, and hierarchical summary receiver operating characteristic (HSROC) curves. We performed a meta-regression analysis to explore the source of study heterogeneity. Results: Eleven studies involving 752 patients were included. US exhibited a pooled sensitivity of 86% (95% confidence interval (CI) 72–94), pooled specificity of 88% (95% CI 78–94), and HSROC of 0.93 in 10 studies. MRE exhibited a pooled sensitivity of 88% (95% CI 76–95), pooled specificity of 87% (95% CI 73–95), and an HSROC of 0.94 in eight studies. In seven studies comparing the diagnostic performances of US and MRE, the summary sensitivity of US and MRE were 86% (95% CI 65–96, I² = 92.1) and 86% (95% CI 72–93, I² = 88.1) (p = 0.841), respectively. The summary specificity of US and MRE were 87% (95% CI 78–93, I² = 79.8%) and 84% (72–90, I² = 72.5%) (p = 0.431), respectively, which showed no statistical differences. On meta-regression analysis, studies from Europe (p = 0.002), those that used linear US probes (p = 0.012), those on small bowel lesions (p = 0.01), and those with outcomes as combined features (active inflammation) reported higher US sensitivity than those from other regions, those that used both linear and convex US probes, those on small and large bowels, and those with outcome as one feature (bowel wall thickening or ulcer). Studies with pediatric patients (p = 0.001), those with reference standards including US (p = 0.001), and outcomes as combined features (p = 0.01) reported higher MRE specificity than those with adult populations, reference standards other than the US, and outcomes as one feature. Conclusions: In spite of considerable heterogeneity in the included studies, both US and MRE can diagnose active bowel lesions with comparable diagnostic accuracy in patients with CD. The study region, type of US probe, lesion location, investigated outcome for US sensitivity and study population, reference standards, and investigated outcomes for MRE specificity were potential sources of heterogeneity.

Diagnostic Utility of Non-invasive Tests for Inflammatory Bowel Disease: An Umbrella Review

BACKGROUND

This study aims to consolidate evidence from published systematic reviews and meta-analyses evaluating the diagnostic performances of non-invasive tests for inflammatory bowel disease (IBD) in various clinical conditions and age groups.

METHODS

Two independent reviewers systematically identified and appraised systematic reviews and meta-analyses assessing the diagnostic utility of non-invasive tests for IBD. Each association was categorized as adults, children, and mixed population, based on the age ranges of patients included in the primary studies. We classified clinical scenarios into diagnosis, activity assessment, and predicting recurrence.

RESULTS

In total, 106 assessments from 43 reviews were included, with 17 non-invasive tests. Fecal calprotectin (FC) and fecal lactoferrin (FL) were the most sensitive for distinguishing IBD from non-IBD. However, anti-neutrophil cytoplasmic antibodies (ANCA) and FL were the most specific for it. FC and FL were the most sensitive and specific tests, respectively, to distinguish IBD from irritable bowel syndrome (IBS). Anti-Saccharomyces cerevisiae antibodies (ASCA), IgA, were the best test to distinguish Crohn's disease (CD) from ulcerative colitis (UC). Interferon-γ release assay was the best test to distinguish CD from intestinal tuberculosis (ITB). Ultrasound (US) and magnetic resonance enterography (MRE) were both sensitive and specific for disease activity, along with the high sensitivity of FC. Small intestine contrast ultrasonography (SICUS) had the highest sensitivity, and FC had the highest specificity for operative CD recurrence.

CONCLUSION

In this umbrella review, we summarized the diagnostic performance of non-invasive tests for IBD in various clinical conditions and age groups. Clinicians can use the suggested non-invasive test depending on the appropriate clinical situation in IBD patients.

Capsule endoscopy - a non-invasive modality to investigate the GI tract: out with the old and in with the new?

INTRODUCTION

Capsule endoscopy has had significant development since it was introduced into the field of medicine in 2000. It is non-invasive, well tolerated, does not require sedation and is a first-line small bowel investigative modality. As it transits through the entire gastrointestinal (GI) tract, it has the potential to provide a pan-enteric examination.

AREAS COVERED

In this review we will discuss the new diagnostic modalities along with traditional methods which have been used for examination of the gastro intestinal (GI) tract. The main focus of this review will be on the use of capsule endoscopy for pan-enteric examination.

EXPERT OPINION

Capsule endoscopy is an accepted first-line investigation for the small bowel. Diagnostic sensitivity of the colon capsule is comparable to colonoscopy in controlled trials and is being evaluated in high-risk patients in routine clinical practice in national programs. Preliminary data suggest that a magnetic-controlled examination of the upper GI tract could be developed to enable a complete upper GI examination.

Ultrasound use to assess Crohn's disease in the UK: a survey of British Society of Gastroenterology Inflammatory Bowel Disease Group members

BACKGROUND

Small bowel ultrasound has very good diagnostic accuracy for disease extent, presence and activity in Crohn's Disease, is well tolerated by patients and is cheaper when compared with MRI. However, uptake of ultrasound in the UK is limited.

METHODS

An online survey to assess the current usage of ultrasound throughout the UK was undertaken by BSG IBD group members between 9/06/2021- 25/06/2021. Responses were anonymous.

RESULTS

103 responses were included in the data analysis. Responses came from 66 different NHS trusts from 14 different regions of the UK. All respondents reported that they currently have an MRI service for Crohn's disease, whereas only 31 had an ultrasound service. Average time for results to be reported for MRI scans was reported as between 4- and 6 weeks, with a range of 2 days to 28 weeks. The average time for an ultrasound to be reported was stated as 1-4 weeks, with a range of 0-8 weeks. There was disparity between the reported confidence of clinicians making clinical decisions when using ultrasound compared to MRI. Of those respondents who did not have access to an ultrasound service, 72 stated that they would be interested in developing an ultrasound service.

CONCLUSION

There is an appetite for the uptake of ultrasound in the UK for assessment of Crohn's disease, however, there remains a significant number of UK centres with little or no access to an ultrasound service. Further research is necessary to understand why this is the case.

Diagnostic Accuracy of Magnetic Resonance Enterography in the Evaluation of Colonic Abnormalities in Crohn's Disease: A Systematic Review and Meta-Analysis

OBJECTIVES

To Evaluate the diagnostic performance of magnetic resonance enterography (MRE) for detecting colonic involvement of Crohn's disease (CD).

MATERIALS AND METHODS

A systematic search of the electronic bibliographic databases was conducted. The inclusion criteria of published original articles were: (1) Utilized MRE to evaluate colon; (2) Patients with documented CD by colonoscopy; (3) Provided crude data of diagnostic performance in the large bowel; (4) Performed segmental evaluation. The colorectal segments were defined as the right colon, transverse colon, left colon, and rectum. A hierarchical bivariate method was used for analysis.

RESULTS

Eleven articles (12 populations and 987 patients) were included. The pooled sensitivity and specificity of the studies were 69% (95% CI: 0.52-0.82) and 95% (95% CI:0.92-0.97), respectively (AUC = 0.95). The pooled positive and negative likelihood ratios were 14 (95% CI:7.5-26.3) and 0.31 (95% CI:0.19-0.51), respectively. Regarding segments, the left colon had the highest sensitivity (60%) and lowest specificity (92%), while the transverse colon showed lowest sensitivity (49%) and highest specificity (95%). Comparing the age groups, MRE sensitivity and specificity was 80% and 95%, versus 62% and 94%, in pediatrics and adults respectively.

CONCLUSION

MRE has a high specificity to detect colon pathologies in CD, while the sensitivity is low. Therefore, the test has a high value to rule in CD, while negative results are not sufficient to rule it out. Meanwhile, considering the higher sensitivity rate of the test in pediatrics, it has the potential to be used as a first-line investigation.

Detection of intramural fat accumulation by 3D-Dixon-Caipirinha-Vibe and the contribution of this technique to the determination of the chronicity of Chron's disease

OBJECTIVES

In this study; we aimed to evaluate the efficacy of the 3D-Dixon-Caipirinha-Vibe fat images in detecting intramural fat accumulation (IFA) and contributions of 3D-Dixon-Caipirinha-Vibe in the management of patients with Chron's disease.

METHODS

Eighty-five patients who had a 3-tesla MR enterography (MRE) with the 3D-Dixon-Caipirinha-Vibe technique were included. Wall thickness, ADC-value, intramural edema, presence/extension of IFA, and contrast-material enhancement of the affected segments were examined. Findings of MRE were compared statistically with clinical, laboratory, endoscopy, and pathological exams.

RESULTS

The presence of IFA was more common in patients with chronic active and chronic inflammation than only active inflammation and normal cases. Patients with IFA had a longer disease duration than patients without IFA. IFA-containing segment lengths of patients with chronic active inflammation and chronic inflammation were found to be longer than those with active inflammation. It was found that patients whose pathology results were reported as active inflammation contained less IFA than patients with chronic inflammation.

CONCLUSIONS

The presence of IFA is strongly related to chronicity. 3D-Dixon-Caipirinha-Vibe is a fast, easy, and useful method for detecting IFA and evaluating Chron's disease.

Magnetic resonance imaging in the management of Crohn's disease: a systematic review and meta-analysis

Objectives

Crohn’s disease (CD) is a condition that can occur in any part of the gastrointestinal tract, although usually forms in the colon and terminal ileum. Magnetic resonance imaging (MRI) has become a beneficial modality in the evaluation of small bowel activity. This study reports on a systematic review and meta-analysis of magnetic resonance enterography for the prediction of CD activity and evaluation of outcomes and possible complications.

Methods

Following the PRISMA guidelines, a total of 25 low-risk studies on established CD were selected, based on a QUADAS-II score of ≥ 9.

Results

A sensitivity of 90% was revealed in a pooled analysis of the 19 studies, with heterogeneity of χ² = 81.83 and I² of 80.3%. Also, a specificity of 89% was calculated, with heterogeneity of χ² = 65.12 and I² of 70.0%.

Conclusion

It was concluded that MRI provides an effective alternative to CT enterography in the detection of small bowel activity in CD patients under supervision of radiologist for assessment of disease activity and its complications. Its advantages include the avoidance of radiation exposure and good diagnostic accuracy.

Diagnostic performance of magnetic resonance enterography and ultrasound in children with inflammatory bowel diseases: a diagnostic test accuracy meta-analysis

OBJECTIVES

Magnetic resonance enterography (MRE) and ultrasound (US) can be used to diagnose inflammatory bowel diseases (IBD) in children. This meta-analysis aimed to determine the diagnostic performance of MRE and US in pediatric patients with IBD.

METHODS

PubMed, Embase, and the Cochrane Library were searched for eligible studies published up to June 1, 2020. The outcomes were the performances of MRE and US at the segment and patient levels. Pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR), and the area under the summary receiver operating characteristic curves value (SROC) were analyzed.

RESULTS

Eight studies (340 children) were included. Compared with the reference standard, MRE showed pooled sensitivity of 93.0% (95% confidence interval (CI): 90.0-95.4%), specificity of 94.6% (95% CI: 92.1-96.5%), PLR of 11.146 (95% CI: 5.027-24.713), NLR of 0.094 (95% CI: 0.057-0.155), and DOR of 134.21 (95% CI: 40.72-442.29), with a SROC of 0.9721. Similar results were observed at the patient and segment levels. Compared with the reference standard, US had pooled sensitivity of 84.1% (95% CI: 69.9-93.4%), specificity of 82.9% (95% CI: 66.4-93.4%), PLR of 4.924 (95% CI: 2.351-10.310), NLR of 0.207 (95% CI: 0.103-0.413), and DOR of 25.919 (95% CI: 7.63-88.07), but only two studies were included. US (reader 1) had a similar diagnostic value to US (reader 2).

CONCLUSIONS

The present meta-analysis shows that MRE has good performance in detecting IBD in pediatric patients. Only two studies used US, and additional studies are necessary to confirm the diagnostic performance of US for IBD in children.

KEY POINTS

• MRE has good performance in the detection of IBD in pediatric patients. • Similar results were observed at the patient and segment levels for MRE. • Only two studies were included for US, without differentiating patient/segment.

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

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.

Clinical utilization of magnetic resonance enterography in small bowel Crohn's disease management: a retrospective tertiary centre experience

BACKGROUND

Magnetic resonance enterography (MRE) is the mainstay imaging modality in the evaluation of small bowel Crohn's disease (CD) activity and its associated complications. Few studies have assessed the indications for ordering it and its association with management changes. The objective was to identify the current clinical utilization of MRE and associated management changes in patients with established small bowel CD.

METHODS

A retrospective audit was conducted on all patients with established CD who underwent MRE at a tertiary centre from November 2014 to December 2017. Clinical indications, radiological findings and management changes were obtained from patient records.

RESULTS

A total of 220 patients underwent a total of 287 MRE examinations. The most common indications for ordering MREs were based on patient symptoms (n = 204, 71.1%) and routine disease surveillance (n = 57, 19.9%). The most common radiological findings were inflammation (n = 156, 54.4%) and strictures (n = 98, 34.1%). Management changes post MRE occurred in 152 of 287 (53%) cases. Of the 152 patients, 87 (57.2%) had changes in medical management, 40 (26.3%) had surgical or endoscopic intervention and 25 (16.4%) had both medical and surgical management changes. Management changes following MRE in patients with new or concerning symptoms were significantly higher than in surveillance patients (OR 4.1, P = 0.000003).

CONCLUSION

This study provides a foundation for understanding the current utilization of MRE in small bowel CD at a tertiary centre. However, its role in altering management particularly within surveillance patients is yet to be defined. Future prospective trials are required to better delineate its role and develop an algorithm for small bowel CD management.

[Preparation, Technique, and Imaging of Computed Tomography/Magnetic Resonance Enterography]

CT enterography and magnetic resonance (MR) enterography are widely used imaging modalities used to examine the small bowel. These radiologic tests are distinguished from routine abdominopelvic CT and MRI by the oral ingestion of a large amount of neutral contrast to distend the small bowel before scanning. For achievement of high quality, diagnostic images and proper technique are required. Conducted protocols still vary in patient preparation, enteric contrast, and CT and MRI acquisition sequences, resulting in heterogeneous diagnostic accuracy. The purpose of this article is to review the processes and techniques that optimize CT/MR enterography for patients with suspected Crohn's disease or other small bowel diseases.

Exploratory clinical characterization of experimentally-induced ulcerative colitis nonhuman primates

A limitation of currently used preclinical models of colitis is that disease and treatment assessment methods differ from clinically used methods. Thus, a modified Mayo score and an endoscopic index (EI) were developed for use in cynomolgus macaques with 0.25% dextran sulfate sodium (DSS)-induced ulcerative colitis. Macaques were treated with water with DSS for two weeks followed by water without DSS for two weeks. Disease activity was classified according to a modified Mayo score: stool consistency, rectal bleeding, colonoscopy examination and global assessment. Findings on colonoscopy were further graded according the Rachmilewitz EI. To demonstrate the sensitivity of the modified Mayo score and EI to therapeutic intervention, macaques were treated with the anti-inflammatory steroid prednisolone followed eight weeks later by the integrin antibody vedolizumab. Before DSS treatment, normal stool consistency and no rectal bleeding were observed. Colonoscopy demonstrated no mucosal abnormalities. Following the first DSS treatment, Mayo score and EI indicated signs of mild colitis. Following subsequent DSS treatments, mild to moderate colitis emerged with each DSS treatment and reduced signs of colitis were observed 2 weeks after DSS treatment termination. Prednisolone treatment during DSS treatment suppressed the emergence of colitis. Vedolizumab reduced signs of colitis during DSS treatment and further reduced signs of colitis that persisted after termination of DSS treatment. The current study demonstrated the potential of utilizing clinical outcome measures to assess experimentally-induced colitis in the macaque. Furthermore, signs of colitis, as assessed with the current methods, were reduced following therapeutic treatment. The current findings suggest that clinically relevant outcome measures in the macaque model of ulcerative colitis could be used to test novel treatments.

Ultrasound vs Endoscopy, Surgery, or Pathology for the Diagnosis of Small Bowel Crohn's Disease and its Complications

BACKGROUND

In patients with inflammatory bowel disease, we strive to achieve mucosal healing, as this has been shown to decrease the risk of disease flares, hospitalization, and surgery. For this reason, we must use objective measures of mucosal healing to inform our clinical decision-making and can no longer rely on patient symptoms alone. Assessment of small bowel Crohn's disease (SBCD) is particularly challenging given its lack of accessibility via standard endoscopic techniques. Ultrasound (US) represents a readily available, cost-effective, minimally invasive, radiation-free alternative for the assessment of small bowel disease. In this study, we performed a systematic review to determine the accuracy of ultrasound in diagnosing SBCD and its complications as compared with endoscopic visualization, surgery, and/or pathology.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL. Prospective cohort studies published up to March 2017 were reviewed. References meeting all eligibility criteria were assessed at the full-text level by 2 independent reviewers. Sensitivity and specificity were collected where available.

RESULTS

A total of 2817 unique references were identified. Twenty-two studies were included. All studies were at low-moderate risk of bias based on the Quality Assessment of Diagnostic Accuracy Studies criteria. Transabdominal US (TAUS) yielded moderately high sensitivity and specificity for the diagnosis of SBCD and its postoperative recurrence. Detection was more accurate for severe postoperative recurrence. The diagnostic accuracy of US in stricture and abscess detection was high. Contrast enhancement improved the detection of abscess. Diagnostic detection of fistulas was of moderate accuracy. Entero-enteric fistulization and entero-mesenteric fistulization were most clearly identified.

CONCLUSIONS

Ultrasound can be used to diagnose SBCD in those with known or suspected Crohn's disease. It can be used to detect postoperative recurrence and can accurately identify abscesses and fistulas, especially with the aid of contrast enhancement.

Diagnostic accuracy of magnetic resonance enterography and small bowel ultrasound for the extent and activity of newly diagnosed and relapsed Crohn's disease (METRIC): a multicentre trial

BACKGROUND

Magnetic resonance enterography (MRE) and ultrasound are used to image Crohn's disease, but their comparative accuracy for assessing disease extent and activity is not known with certainty. Therefore, we did a multicentre trial to address this issue.

METHODS

We recruited patients from eight UK hospitals. Eligible patients were 16 years or older, with newly diagnosed Crohn's disease or with established disease and suspected relapse. Consecutive patients had MRE and ultrasound in addition to standard investigations. Discrepancy between MRE and ultrasound for the presence of small bowel disease triggered an additional investigation, if not already available. The primary outcome was difference in per-patient sensitivity for small bowel disease extent (correct identification and segmental localisation) against a construct reference standard (panel diagnosis). This trial is registered with the International Standard Randomised Controlled Trial, number ISRCTN03982913, and has been completed.

FINDINGS

284 patients completed the trial (133 in the newly diagnosed group, 151 in the relapse group). Based on the reference standard, 233 (82%) patients had small bowel Crohn's disease. The sensitivity of MRE for small bowel disease extent (80% [95% CI 72-86]) and presence (97% [91-99]) were significantly greater than that of ultrasound (70% [62-78] for disease extent, 92% [84-96] for disease presence); a 10% (95% CI 1-18; p=0·027) difference for extent, and 5% (1-9; p=0·025) difference for presence. The specificity of MRE for small bowel disease extent (95% [85-98]) was significantly greater than that of ultrasound (81% [64-91]); a difference of 14% (1-27; p=0·039). The specificity for small bowel disease presence was 96% (95% CI 86-99) with MRE and 84% (65-94) with ultrasound (difference 12% [0-25]; p=0·054). There were no serious adverse events.

INTERPRETATION

Both MRE and ultrasound have high sensitivity for detecting small bowel disease presence and both are valid first-line investigations, and viable alternatives to ileocolonoscopy. However, in a national health service setting, MRE is generally the preferred radiological investigation when available because its sensitivity and specificity exceed ultrasound significantly.

FUNDING

National Institute of Health and Research Health Technology Assessment.

Diagnostic Performance of Magnetic Resonance Enterography for Detection of Active Inflammation in Children and Adolescents With Inflammatory Bowel Disease: A Systematic Review and Diagnostic Meta-analysis

Importance

Magnetic resonance (MR) enterography has the advantage over other techniques of being noninvasive, lacking ionizing radiation, and demonstrating excellent soft-tissue contrast to evaluate pediatric patients with inflammatory bowel disease (IBD).

Objective

To evaluate the diagnostic performance of MR enterography for detection of active inflammation in children and adolescents with known or suspected IBD.

Data Sources

A search of MEDLINE and EMBASE up to January 2, 2017, was performed to identify studies. Search terms included child, pediatric, adolescent, Crohn disease, inflammatory bowel disease, and magnetic resonance enterography. The search was limited to English-language publications.

Study Selection

Studies evaluating the diagnostic performance of MR enterography for detection of active inflammation in pediatric patients with known or suspected IBD were selected. Two reviewers independently assessed the eligibility of the selected articles.

Data Extraction and Synthesis

The study was performed and reported in accordance with the PRISMA guidelines. Pooled summary estimates of sensitivity and specificity were calculated using hierarchical logistic regression modeling.

Main Outcomes and Measures

The diagnostic performance of MR enterography for detection of active inflammation in pediatric patients with known or suspected IBD was the primary outcome. Subgroup analyses and meta-regression were performed.

Results

Eighteen original articles involving a total of 687 patients were included. The summary sensitivity was 83% (95% CI, 75%-89%), the summary specificity was 93% (95% CI, 90%-95%), and the area under the hierarchical summary receiver operating characteristic curve was 0.95 (95% CI, 0.93-0.97). The Higgins I2 statistics demonstrated substantial heterogeneity in terms of sensitivity (I2 = 84.1%) and specificity (I2 = 68.8%). Based on per-patient analysis, the summary sensitivity was 86% (95% CI, 78%-91%) and specificity was 91% (95% CI, 82%-96%). In meta-regression, among the various potential covariates, scanner manufacturer was associated with study heterogeneity.

Conclusions and Relevance

Magnetic resonance enterography, which is a noninvasive, radiation-free modality, demonstrates high diagnostic performance in the diagnosis of active inflammation in pediatric patients with IBD, especially at the per-patient level.