Validation of the Simplified Magnetic Resonance Index of Activity [sMARIA] Without Gadolinium-enhanced Sequences for Crohn's Disease

Magnetic resonance enterography to predict subsequent disabling Crohn's disease in newly diagnosed patients (METRIC-EF)-multivariable prediction model, multicentre diagnostic inception cohort

OBJECTIVES

Magnetic resonance enterography (MRE) is a first-line investigation to diagnose Crohn's disease (CD), but its role for prognostication is unknown. Accordingly, we assessed the predictive ability of prognostic models including MRE scores (MRE Global Score (MEGS), simplified MR Index of Activity (sMARIA), and Lémann index (LI)) against models using clinical predictors alone for the development of modified Beaugerie disabling CD (MBDD) within 5 years of diagnosis.

METHODS

This was a multicentre, diagnostic inception cohort of patients with newly diagnosed CD across 9 UK hospitals, followed for 4 years or more. We censored development of MBDD ≤ 90 days from diagnosis, and used time-to-event models using Royston-Parmer flexible parametric models.

RESULTS

We included 194 patients, median age 29, IQR 22-44 years, 52% female. Within 5 years of diagnosis, 42% (81/194) developed MBDD. In univariable analysis, initial steroid requirement was associated with increased risk of developing MBDD (HR 2.11 (95% CI 1.36, 3.26). The baseline clinical model had 49% (39, 60) sensitivity and 66% (57, 74) specificity for predicting the top 40% of patients with the greatest risk of developing MBDD, and 86% (77, 92) sensitivity and 35% (27, 45) specificity for predicting the development of MBDD in patients with an absolute risk of ≥ 10%. There was no significant difference in sensitivity when the MEGS, sMARIA, or LI were added to the baseline clinical model.

CONCLUSIONS

Addition of MRE scores at diagnosis to a multivariable model comprising clinical predictors did not improve prediction of MBDD within 5 years of diagnosis.

KEY POINTS

Question Magnetic resonance enterography (MRE) is important for diagnosing and monitoring Crohn's disease (CD), but primary research evaluating its prognostic role is lacking. Findings Adding MRE findings at diagnosis to a multivariable model comprising clinical predictors did not improve the prediction of disabling CD within 5 years of diagnosis. Clinical relevance When tested in a prospective, multicentre trial, current MRE activity and damage scores at diagnosis did not reliably predict whether patients would subsequently develop disabling CD. Notwithstanding this finding, MRE remains an essential tool for diagnosis and monitoring.

Assessment of activity and severity of inflammatory bowel disease in cross-sectional imaging techniques: a systematic review

BACKGROUND AND AIMS

Cross-sectional imaging techniques, including intestinal ultrasonography (IUS), computed tomography enterography (CTE), magnetic resonance enterography (MRE), are increasingly used for the evaluation of inflammatory bowel diseases (IBD). We aimed to systematically review literature evidence on the assessment of disease activity, and/or severity through cross-sectional imaging in IBD patients, and to offer guidance on their most effective utilization.

METHODS

We performed a systematic review of PubMed, EMBASE, and Scopus to identify citations pertaining to the assessment of disease activity and/or severity at cross-sectional imaging techniques compared to a reference standard (ie, other radiological techniques, endoscopy, histopathology, and surgery) in IBD patients published until December 2023.

RESULTS

Overall, 179 papers published between 1990 and 2023 were included, with a total of 10 988 IBD patients (9304 Crohn's disease [84.7%], 1206 ulcerative colitis [11.0%], 38 IBD-U [0.3%], 440 unspecified [4.0%]). Of the 179 studies, 39 investigated IUS, 22/179 CTE, and 101/179 MRE. In the remaining papers, 2 techniques were addressed together. In 81.6% of the papers, endoscopy (with or without histopathology) was used as a reference standard. All studies included evaluated disease activity, while just over half (100/179, 55.8%) also evaluated disease severity of the addressed cross-sectional methodology. Pooled sensitivity, specificity, and overall accuracy of IUS, MRE, and CTE compared to the reference standard were 60%-99%, 60%-100%, and 70%-99%, respectively.

CONCLUSIONS

All cross-sectional imaging techniques demonstrated moderate-to-good accuracy in assessing disease activity and severity of IBD. This finding highlights the potential, especially for MRE and IUS to be widely utilized in managing IBD in both clinical practice and clinical trials.

Quantified small bowel motility assessment on magnetic resonance enterography in paediatric inflammatory bowel disease - does it reflect clinical response?

BACKGROUND

Quantified small bowel motility assessment using cine magnetic resonance enterography (MRE) has shown promise as a biomarker in adult inflammatory bowel disease. Whether quantified motility corresponds to treatment response in paediatric inflammatory bowel disease is unknown.

OBJECTIVE

To test whether changes in motility reflect response.

MATERIALS AND METHODS

Local ethics approval was granted for this single-institution, retrospective study. All children < 18 years with confirmed inflammatory bowel disease, who had more than one MRE between Jan 2011-Jan 2022, were included. Simplified MaRIA (sMaRIA) and motility index (quantified motility) at all terminal ileum and diseased non-terminal ileum segments were independently assessed by two radiologists each with ≥ 9 years' experience. Change in (Δ) motility index was compared to clinical (gastroenterologist physician's global assessment) and consensus radiological reference standard (response = decrease in sMaRIA of more than or equal to 2 points) in responders versus non-responders using the Mann-Whitney test. Sensitivity and specificity of Δ motility index more than zero were compared to decrease in sMaRIA of 2 or more points for identifying clinical response.

RESULTS

Of 64 children aged 5-16, 21 out of 64 (33%) were responders, 37 out of 64 (58%) were non-responders and 6 out of 64 (9%) had inactive disease according to clinical reference standard. Δ Motility index by both radiologists was higher in responders (+ 16, + 39) than non-responders (-43, -44), P = 0.04, P = 0.01 each radiologist, respectively. Motility index was more sensitive (57% versus 24%), but less specific (67% versus 93%) than sMaRIA in identifying clinical response.

CONCLUSION

Motility index on cine MRE corresponds to clinical response, and is more sensitive at detecting response compared to sMaRIA in paediatric inflammatory bowel disease.

Magnetic Resonance Enterography and Intestinal Ultrasound for the Assessment and Monitoring of Crohn's Disease

Magnetic resonance enterography [MRE] and intestinal ultrasound [IUS] have developed rapidly in the past few decades, emerging as the primary non-invasive options for both diagnosing and monitoring Crohn's disease [CD]. In this review, we evaluate the pertinent data relating to the use of MRE and IUS in CD. We summarise the key imaging features of CD activity, highlight their increasing role in both the clinical and the research settings, and discuss how these modalities fit within the diagnostic pathway. We discuss how they can be used to assess disease activity and treatment responsiveness, including the emergence of activity scores for standardised reporting. Additionally, we address areas of controversy such as the use of contrast agents, the role of diffusion-weighted imaging, and point-of-care ultrasound. We also highlight exciting new developments, including the applications of artificial intelligence. Finally, we provide suggestions for future research priorities.

The Relationship Between the Endoscopic Healing Index, Fecal Calprotectin, and Magnetic Resonance Enterography in Crohn's Disease

INTRODUCTION

The serum-based endoscopic healing index (EHI) test identifies endoscopic Crohn's disease (CD) activity. Data are lacking on the relationship between EHI with other endpoints. We assessed the relationship between EHI and the simplified Magnetic Resonance Index of Activity.

MATERIALS AND METHODS

Data were prospectively collected on patients with CD with either an EHI or fecal calprotectin (FCAL) within 90 days of magnetic resonance enterography (MRE). Diagnostic accuracy was assessed using area under the receiver operator characteristics. Proportions with any, severe, and terminal ileum MR inflammation were compared above/below identified thresholds for both EHI and FCAL.

RESULTS

A total of 241 MREs paired to either EHI or FCAL from 155 patients were included. Both EHI and FCAL had similar accuracy to diagnose inflammation (area under the receiver operator characteristics: EHI: 0.635 to 0.651, FCAL: 0.680 to 0.708). Optimal EHI values were 42 and 26 for inflammation on MRE and endoscopy, respectively. Patients with EHI ≥42 (100% vs. 63%, P =0.002), FCAL >50 µg/g (87% vs. 64%, P <0.001) and FCAL >250 µg/g (90% vs. 75%, P =0.02) had higher rates of simplified Magnetic Resonance Index of Activity ≥1 compared with lower values. EHI differentiated ileitis numerically more than FCAL (delta: 24% to 25% vs. 11% to 21%). Patients with FCAL ≥50 µg/g had higher rates of severe inflammation compared with FCAL <50 µg/g (75% vs. 47%, P <0.001), whereas smaller differentiation existed for EHI threshold of 42 (63% vs. 49%, P =0.35).

CONCLUSION

Both EHI and FCAL were specific in their confirmation of inflammation and disease activity on MRE in patients with CD. However, MRE-detected inflammation was frequently present in the presence of low EHI and FCAL in similar proportions.

Intestinal Ultrasound and MRI for Monitoring Therapeutic Response in Luminal Crohn's Disease: A Systematic Review

PURPOSE

Cross-sectional imaging facilitates the assessment of transmural healing in patients with Crohn's disease. This systematic review addresses the utility of MRI and intestinal ultrasound (IUS) in the assessment of disease activity in response to drug therapy compared with endoscopy in patients with luminal Crohn's disease.

METHODS

Database searches were undertaken using predefined terms. Studies with ≥10 patients with luminal Crohn's disease with paired endoscopy and imaging (MRI or IUS) after treatment initiation were included. Publications were identified through searches of six bibliographic databases, all run on June 24, 2022. Records were screened on title and abstract, then full text, by two independent reviewers.

RESULTS

In total, 5,760 records were identified, with 24 studies meeting the inclusion criteria. Ten studies examined IUS and found good correlation between IUS and endoscopic remission (κ = 0.63-0.73). Early reduction in bowel wall thickness at 4 to 8 weeks predicted endoscopic response at 12 to 38 weeks (area under the receiver operating characteristic curve [AUROC], 0.77; odds ratio, 10.8; P = .01). Twelve studies examined MRI, with the Magnetic Resonance Index of Activity score having high accuracy for predicting endoscopic remission (AUROC, 0.97; sensitivity, 93%; specificity, 77%). A Simplified Magnetic Resonance Index of Activity score cutoff of ≥1 identifies active endoscopic disease (AUROC, 0.92; 95% confidence interval, 0.88-0.95; P < .0001).

CONCLUSIONS

IUS and MRI are both reliable, noninvasive modalities for assessing transmural healing in patients with Crohn's disease and are accurate in monitoring the response to drug therapy. These modalities can be used to monitor response to biologic induction therapy, with early changes predictive of response to treatment.

Magnetic Resonance Enterography Assessment of Transmural Healing with Vedolizumab in Moderate to Severe Crohn's Disease: Feasibility in the VERSIFY Phase 3 Clinical Trial

Purpose

The VERSIFY phase 3 trial in patients with Crohn's disease (CD) treated with vedolizumab was the first to include a substudy that used a standardized magnetic resonance enterography (MRE) protocol to assess features of transmural inflammation (bowel edema and wall thickness) and extramural disease activity (enlarged lymph nodes).

Patients and Methods

Patients received intravenous vedolizumab (300 mg) at weeks 0 (baseline), 2, and 6, and then every 8 weeks for 26 or 52 weeks. Post hoc analyses included a subpopulation with a Magnetic Resonance Index of Activity score of ≥7 in at least one bowel segment at baseline and at least one postbaseline MRE assessment. Changes in transmural inflammation, including intramural bowel edema and wall thickness, were evaluated. Patient-level and segment-level analyses were performed.

Results

MRE images were evaluated in 27 patients with 83 evaluable bowel segments at baseline and week 26, and 13 patients with 38 evaluable segments at baseline, week 26, and week 52. At baseline, all patients had bowel wall edema and wall thickness of >3 mm in at least one bowel segment. The proportion of patients with edema decreased at weeks 26 (17/27 [63.0%]) and 52 (4/13 [30.8%]) and the proportion with bowel wall thickness of >3 mm decreased at weeks 26 (25/27 [92.6%]) and 52 (10/13 [76.9%]).

Conclusion

In patients with CD treated with vedolizumab for 26 and 52 weeks, the number of patients, and bowel segments, with MRE-detected transmural inflammation was reduced. These results highlight the impact of vedolizumab on components of transmural inflammation in CD and demonstrate that using MRE in CD multicenter clinical trials is feasible.

Trial Registration

ClinicalTrials.gov NCT02425111, April 23, 2015, http://www.clinicaltrials.gov NCT02425111; EU Clinical Trials Register EudraCT 2014-003509-13, https://www.clinicaltrialsregister.eu.

Comparison of an Endoscopic Scoring System and the Simplified Magnetic Resonance Index of Activity in Patients with Small Bowel Crohn's Disease

Background/Aims

The newly derived simplified magnetic resonance index of activity (MARIAs) has not been verified in comparison to balloon-assisted enteroscopy (BAE) for patients with small bowel Crohn's disease (CD). We studied the correlation of MARIAs with simple endoscopic scores for CD (SES-CD) of the ileum based on magnetic resonance enterography (MRE) and BAE in patients with small bowel CD.

Methods

Fifty patients with small bowel CD who underwent BAE and MRE concurrently within 3 months from September 2020 to June 2021 were enrolled in the study. The primary outcome was the correlation between the active score of ileal SES-CD (ileal SES-CDa)/ileal SES-CD and MARIAs based on BAE and MRE. The cutoff value for MARIAs identifying endoscopically active/severe disease, defined as ileal SES-CDa/ileal SES-CD of 5/7 or more, was analyzed.

Results

Ileal SES-CDa/ileal SES-CD and MARIAs showed strong associations (R=0.76, p<0.001; R=0.78, p<0.001). The area under the receiver operating characteristic curve of MARIAs for ileal SES-CDa ≥5 and ileal SES-CD ≥7 was 0.92 (95% confidence interval, 0.88 to 0.97) and 0.92 (95% confidence interval, 0.87 to 0.97). The cutoff value of MARIAs for detecting active/severe disease was 3. A MARIAs index value of ≥3 identified ileal SES-CDa ≥5 with a sensitivity of 85% and specificity of 87% and detected ileal SES-CD ≥7 with a sensitivity of 87% and specificity of 86%.

Conclusions

This study validated the applicability of MARIAs compared to BAE-based ileal SES-CDa/SES-CD.

Diagnostic performance of sonographic activity scores for adult terminal ileal Crohn's disease compared to magnetic resonance and histological reference standards: experience from the METRIC trial

OBJECTIVES

The simple ultrasound activity score for Crohn's disease (SUS-CD) and bowel ultrasound score (BUSS) are promising intestinal ultrasound (IUS) indices of CD, but studied mainly in small settings with few sonographers. We compared SUS-CD and BUSS against histological and magnetic resonance enterography (MRE) reference standards in a post hoc analysis of a prospective multicentre, multireader trial.

METHODS

Participants recruited to the METRIC trial (ISRCTN03982913) were studied, including those with available terminal ileal (TI) biopsies. Sensitivity and specificity of SUS-CD and BUSS for TI CD activity were calculated with 95% confidence intervals (CI), from the prospective observations of the original METRIC trial sonographers against the histological activity index (HAI) and the simplified magnetic resonance index of activity (sMARIA).

RESULTS

We included 284 patients (median 31.5 years, IQR 23-46) from 8 centres, who underwent IUS and MRE. Of these, 111 patients had available terminal ileal biopsies with HAI scoring. Against histology, sensitivity and specificity for active disease were 79% (95% CI 69-86%) and 50% (31-69%) for SUS-CD, and 66% (56-75%) and 68% (47-84%) for BUSS, respectively. Compared to sMARIA, the sensitivity and specificity for active CD were 81% (74-86%) and 75% (66-83%) for SUS-CD, and 68% (61-74%) and 85% (76-91%) for BUSS, respectively. The sensitivity of SUS-CD was significantly greater than that of BUSS against HAI and sMARIA (p < 0.001), but its specificity was significantly lower than of BUSS against the MRE reference standard (p = 0.003).

CONCLUSIONS

Particularly when compared to MRE activity scoring, SUS-CD and BUSS are promising tools in a real-world clinical setting.

CLINICAL RELEVANCE STATEMENT

When tested using data from a multicentre, multireader diagnostic accuracy trial, the simple ultrasound activity score for Crohn's disease (SUS-CD) and bowel ultrasound score (BUSS) were clinically viable intestinal ultrasound indices that were reasonably sensitive and specific for terminal ileal Crohn's disease, especially when compared to a magnetic resonance reference standard.

KEY POINTS

The simple ultrasound activity score for Crohn's disease and bowel ultrasound score are promising intestinal ultrasound indices of Crohn's disease but to date studied mainly in small settings with few sonographers. Compared to histology and the magnetic resonance reference standard in a multicentre, multireader setting, the sensitivity of simple ultrasound activity score for Crohn's disease is significantly greater than that of bowel ultrasound score. The specificity of simple ultrasound activity score for Crohn's disease was significantly lower than that of bowel ultrasound score compared to the magnetic resonance enterography reference standard. The specificity of both indices was numerically higher when the magnetic resonance enterography reference standard was adopted.

Serum Ustekinumab Concentrations Are Associated With Improved Outcomes With the Magnetic Resonance Index of Activity for Crohn's Disease

Higher ustekinumab concentrations were associated with improved radiologic (Simplified Magnetic Resonance Index of Activity for Crohn’s Disease) and stringent biomarker (calprotectin) outcomes. The high concentration needed for these novel endpoints validates previous studies using the same assay.

Comparison of the magnetic resonance scoring systems for Crohn's disease activity: MaRIA, simplified MaRIA, and Nancy scores

PURPOSE

The most widely used score for assessing the activity of Crohn's disease (CD) is the Magnetic Resonance Index of Activity (MaRIA) score, but it is time-consuming. The aim of this study was to compare the diagnostic accuracy of MaRIA score to the other two easily calculated scores.

METHODS

Between January 2011 and May 2021, 67 patients with CD who underwent MRE and ileocolonoscopy within 2 weeks were enrolled. The MRE-based scores including the MaRIA score, simplified MaRIA (sMaRIA) score, and Nancy score for each colonic segment and terminal ileum were calculated and correlated with the ileocolonoscopic findings. The simplified endoscopic score for Crohn's disease (SES-CD) was considered the gold standard.

RESULTS

A total of 343 intestinal segments were included in the analysis, of which 109 (31.8%) showed active inflammation on ileocolonoscopy. The areas under the receiver operating characteristic curve (AUC) of the MaRIA, sMaRIA, and Nancy scores for detecting active disease were 0.752, 0.764, and 0.765, respectively. In the sub-analysis for different indications, the MaRIA and sMaRIA scores showed a higher AUC (0.721 and 0.741) than the Nancy score (0.652) for disease monitoring.

CONCLUSION

The sMARIA and Nancy scores showed comparable diagnostic accuracy to the MaRIA score, and thus could be used as alternatives to the MaRIA score. Furthermore, considering the range of application, especially for disease monitoring, the sMaRIA score may be more suitable for use in clinical practice.

Small bowel imaging in inflammatory bowel disease: updates for 2023

INTRODUCTION

Cross-sectional imaging techniques including MR and CT enterography and ultrasound are integral to Crohn's disease management, accurate, responsive, and well tolerated. They assess the full thickness of the bowel wall, perienteric environment, and distant complications. As we strive toward tighter disease control, imaging's role will expand further with transmural healing becoming an increasingly important therapeutic target.

AREAS COVERED

MEDLINE and Web of Science were searched from 2012 to 2023 inclusive. We review the evidence for cross-sectional imaging in assessing disease activity, phenotyping, and therapeutic response assessment. Emerging novel imaging applications such as quantifying enteric motility and fibrosis, prognostication, and potential utility of artificial intelligence will be covered. Recent international consensus statements highlight the need for standardized imaging reporting and definitions of transmural healing and remission. We will discuss how recent advances may be best integrated into patient care and highlight key outstanding research questions.

EXPERT OPINION

Cross-sectional imaging is established in Crohn's disease management. Research emphasis should be placed on optimal integration of imaging modalities in clinical care pathways, workforce training, definitions, and evidence for use of imaging based therapeutic targets such as transmural healing, better phenotyping of stricturing disease, and developing novel techniques, including integration of artificial intelligence.

Validation of the simplified magnetic resonance index of activity by using DWI without gadolinium enhancement to evaluate bowel inflammation in Crohn's disease

OBJECTIVES

To validate the modified simplified magnetic resonance index of activity (sMARIA) score using DWI on non-contrast magnetic resonance enterography (MRE) to evaluate active inflammation in patients with Crohn's disease (CD), compared to the original sMARIA scoring system, with and without contrast enhancement.

METHODS

This retrospective study included 275 bowel segments from 55 CD patients who underwent ileocolonoscopy and MRE within a 2-week period. Two blinded radiologists evaluated original sMARIA on both conventional MRE (CE-sMARIA) and non-contrast MRE (T2-sMARIA). Modified sMARIA was then evaluated using non-contrast MRE, replacing ulcerations with DWI grades. Three scoring systems were compared for diagnostic accuracy of active inflammation, correlation with simple endoscopic score (SES)-CD, and interobserver reproducibility.

RESULTS

The AUC of modified sMARIA for detecting active inflammation (0.863, 95% confidence interval [0.803-0.923]) was significantly higher than T2-sMARIA (0.827 [0.773-0.881], p = 0.017), and comparable to CE-sMARIA (0.908 [0.857-0.959], p = 0.122). CE-sMARIA, T2-sMARIA, and modified sMARIA all showed moderate correlation with SES-CD (r = 0.795, 0.722, and 0.777, respectively). Interobserver reproducibility of diffusion restriction (κ, 0.686 [0.602-0.770]) was significantly better than ulcers on conventional MRE (κ, 0.382 [0.212-0.552]; p = 0.001) and T2-weighted image (κ, 0.312 [0.034-0.590]; p = 0.012).

CONCLUSIONS

Modified sMARIA using DWI can improve the diagnostic performance of sMARIA on non-contrast MRE, showing comparable performance to sMARIA using contrast-enhanced MRE.

KEY POINTS

• DWI can improve the diagnostic performance of non-contrast magnetic resonance enterography (MRE) for assessing active inflammation in patients with Crohn's disease. • Modified simplified magnetic resonance index of activity (sMARIA) using DWI grades in place of ulcers showed comparable diagnostic performance to sMARIA using conventional MRE with contrast-enhanced sequences.

Replacing Endoscopy with Magnetic Resonance Enterography for Mucosal Activity Assessment in Terminal Ileal Crohn's Disease: Are We There Yet?

Crohn's disease (CD) is a chronic immune mediated disorder that most commonly affects the small bowel and/or the large bowel. Treatment targets in CD include mucosal healing assessed via ileocolonoscopy and transmural healing assessed through cross-sectional imaging modalities such as magnetic resonance enterography (MRE). More recently, histological healing in CD has emerged as a treatment target, though it is made cumbersome given its reliance on frequent endoscopic examinations. With expert guidelines now recommending regular objective assessments as part of a treat-to-target approach, accurate non-invasive assessment will become increasingly critical. MRE has an established role in the assessment of small bowel CD, with growing data supportive of its ability in detecting disease activity at mucosal and histological levels. This could therefore potentially reduce the need for serial endoscopic assessment. Thus, this review will assess the capacity of individual MRE parameters and MRE indices for detecting mucosal and histological small bowel CD activity. Furthermore, challenging scenarios, such as CD activity detection in post-operative clinical scenarios and abnormal findings in the context of a normal ileocolonoscopy, will be explored.

The Simplified MR Index of Activity Score in Pediatric Small-Bowel Crohn Disease: An Interreader Agreement and Responsiveness Study

BACKGROUND. The simplified MR index of activity (MaRIA) score is used to assess the severity of small-bowel inflammation without use of IV contrast material. OBJECTIVE. The purposes of this study were to assess interreader agreement on the use of simplified MaRIA scores for evaluation of the inflammatory activity of terminal ileal Crohn disease in children and young adults and to assess whether simplified MaRIA scores change after biologic medical therapy. METHODS. This analysis was ancillary to a previously reported primary prospective research investigation. The study included 20 children and young adults with newly diagnosed ileal Crohn disease and 15 healthy control participants who underwent research small-bowel MRI examinations between December 2018 and October 2021. The participants with Crohn disease underwent baseline MRI and MRI 6 weeks and 6 months after beginning anti-tumor necrosis factor α-treatment as well as weighted pediatric Crohn disease activity index (wPCDAI) and C-reactive protein (CRP) assessment on the day of each examination. Control participants underwent one MRI examination. Four pediatric radiologists independently assigned simplified MaRIA scores using axial and coronal T2-weighted SSFSE images. Median simplified MaRIA score among readers was computed. Interreader agreement was assessed with Fleiss kappa coefficients and intra-class correlation coefficient (ICC). Analysis included the Mann-Whitney U test, Friedman test, and Spearman rank correlation. RESULTS. Simplified MaRIA scores (across time points and study groups) had substantial interreader agreement (κ = 0.65 [95% CI, 0.56-0.74]; ICC, 0.71 [95% CI, 0.63-0.78]). Median scores were higher in participants with Crohn disease at baseline than in healthy control participants (3.5 [IQR, 2.5-4.9] vs 0.5 [IQR, 0-2.0]; p < .001). Scores decreased after medical treatment in participants with Crohn disease (p = .005). The median score was 3.5 (IQR, 2.5-4.9) at baseline, 2.3 (IQR, 1.6-3.9) at 6 weeks, and 2.0 (IQR, 0.5-2.5) at 6 months. In participants with Crohn disease, median scores had significant correlations with wPCDAI (ρ = 0.46 [95% CI, 0.18-0.64]; p < .001) and CRP level (ρ = 0.48 [95% CI, 0.27-0.65]; p < .001). CONCLUSION. Radiologists had substantial agreement in use of simplified MaRIA scores to assess intestinal inflammation in ileal Crohn disease. Scores changed over time after medical therapy. CLINICAL IMPACT. The results support the simplified MaRIA score as an objective MRI-based clinical measure of intestinal inflammation in children and young adults with Crohn disease.

Recent advances in clinical practice: advances in cross-sectional imaging in inflammatory bowel disease

Endoscopy remains the reference standard for the diagnosis and assessment of patients with inflammatory bowel disease (IBD), but it has several important limitations. Cross-sectional imaging techniques such as magnetic resonance enterography (MRE) and intestinal ultrasound (IUS) are better tolerated and safer. Moreover, they can examine the entire bowel, even in patients with stenoses and/or severe inflammation. A variety of cross-sectional imaging activity scores strongly correlate with endoscopic measures of mucosal inflammation in the colon and terminal ileum. Unlike endoscopy, cross-sectional techniques allow complete visualisation of the small-bowel and assess for extraintestinal disease, which occurs in nearly half of patients with IBD. Extramural findings may predict outcomes better than endoscopic mucosal assessment, so cross-sectional techniques might help identify more relevant therapeutic targets. Coupled with their high sensitivity, these advantages have made MRE and IUS the primary non-invasive options for diagnosing and monitoring Crohn's disease; they are appropriate first-line investigations, and have become viable alternatives to colonoscopy. This review discusses cross-sectional imaging in IBD in current clinical practice as well as research lines that will define the future role of these techniques.

Responsiveness of Magnetic Resonance Enterography Indices for Evaluation of Luminal Disease Activity in Crohn's Disease

BACKGROUND & AIMS

Magnetic resonance enterography (MRE) is having an increasing role in Crohn's disease; however, fully validated indices are needed. We evaluated the responsiveness of 4 MRE indices in luminal Crohn's disease.

METHODS

Paired MRE images (pretreatment and post-treatment at weeks 12 or 14) from 41 patients were scored by 3 blinded radiologists. Disease activity was scored for 4 MRE indices (magnetic resonance index of activity [MaRIA], simplified MaRIA, London index, and London extended index) and a 100-mm visual analog scale (VAS) of overall disease activity. The criterion for change was an improvement by at least one half of an SD in the VAS after treatment. Responsiveness was evaluated using the standardized effect size (SES). Longitudinal validity was evaluated using correlations between changes in MRE index scores and disease activity measures including endoscopy and the VAS.

RESULTS

The SES was 1.17 (95% CI, 0.56-1.77) for the simplified MaRIA, 0.98 (95% CI, 0.42-1.55) for the MaRIA, 0.95 (95% CI, 0.38-1.51) for the London extended index, and 0.85 (95% CI, 0.31-1.39) for the London index. The simplified MaRIA was significantly more responsive than the London index (ΔSES, 0.32; 95% CI, 0.05-0.58) but not the MaRIA (ΔSES, 0.18; 95% CI, -0.01 to 0.38) or the London extended index (ΔSES, 0.22; 95% CI, -0.05 to 0.50). Correlations with endoscopy (simplified MaRIA: r = 0.72) were not different from correlations with the VAS (London extended index: r = 0.70).

CONCLUSIONS

Evaluated MRE indices showed moderate-to-large responsiveness and are suitable for use in clinical trials. The simplified MaRIA may be preferred because of its responsiveness and nonreliance on gadolinium administration.

Challenges and Strategies to Optimising the Quality of Small Bowel Magnetic Resonance Imaging in Crohn's Disease

Magnetic resonance enterography (MRE) is one of the most highly utilised tools in the assessment of patients with small bowel Crohn's disease (CD). As a non-invasive modality, it has both patient and procedure-related advantages over ileocolonoscopy which is the current gold standard for Crohn's disease activity assessment. MRE relies upon high-quality images to ensure accurate disease activity assessment; however, few studies have explored the impact of image quality on the accuracy of small bowel CD activity assessment. Bowel distension and motion artifacts are two key imaging parameters that impact the quality of images obtained through MRE. Multiple strategies have been employed to both minimise the effects of motion artifacts and improve bowel distension. This review discusses the definitions of bowel distension and motion artifacts within the literature with a particular focus on current strategies to improve bowel distension and limit motion artifacts in MRE.

METRIC-EF: magnetic resonance enterography to predict disabling disease in newly diagnosed Crohn's disease-protocol for a multicentre, non-randomised, single-arm, prospective study

INTRODUCTION

Crohn's disease (CD) is characterised by discontinuous, relapsing enteric inflammation. Instituting advanced therapies at an early stage to suppress inflammation aims to prevent future complications such as stricturing or penetrating disease, and subsequent surgical resection. Therapeutics are effective but associated with certain side-effects and relatively expensive. There is therefore an urgent need for robust methods to predict which newly diagnosed patients will develop disabling disease, to identify patients who are most likely to benefit from early, advanced therapies. We aim to determine if magnetic resonance enterography (MRE) features at diagnosis improve prediction of disabling CD within 5 years of diagnosis.

METHODS AND ANALYSIS

We describe the protocol for a multicentre, non-randomised, single-arm, prospective study of adult patients with newly diagnosed CD. We will use patients already recruited to the METRIC study and extend their clinical follow-up, as well as a separate group of newly diagnosed patients who were not part of the METRIC trial (MRE within 3 months of diagnosis), to ensure an adequate sample size. Follow-up will extend for at least 4 years. The primary outcome is to evaluate the comparative predictive ability of prognostic models incorporating MRE severity scores (Magnetic resonance Enterography Global Score (MEGS), simplified MAgnetic Resonance Index of Activity (sMaRIA) and Lémann Index) versus models using standard characteristics alone to predict disabling CD (modified Beaugerie definition) within 5 years of new diagnosis.

ETHICS AND DISSEMINATION

This study protocol achieved National Health Service Research Ethics Committee (NHS REC), London-Hampstead Research Ethics Committee approval (IRAS 217422). Our findings will be disseminated via conference presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ISRCTN76899103.

Diagnostic Performance of Magnetic Resonance Enterography Disease Activity Indices Compared with a Histological Reference Standard for Adult Terminal Ileal Crohn's Disease: Experience from the METRIC Trial

BACKGROUND AND AIMS

The simplified magnetic resonance enterography [MRE] index of activity [sMARIA], London, and 'extended' London, scoring systems are widely used in Crohn's disease [CD] to assess disease activity, although validation studies have usually been single-centre, retrospective, and/or used few readers. Here, we evaluated these MRE indices within a prospective, multicentre, multireader, diagnostic accuracy trial.

METHODS

A subset of participants [newly diagnosed or suspected of relapse] recruited to the METRIC trial with available terminal ileal [TI] biopsies was included. Using pre-specified thresholds, the sensitivity and specificity of sMARIA, London, and 'extended' London scores for active and severe [sMARIA] TI CD were calculated using different thresholds for the histological activity index [HAI].

RESULTS

We studied 111 patients [median age 29 years, interquartile range 21-41, 75 newly diagnosed, 36 suspected relapse] from seven centres, of whom 22 had no active TI CD [HAI = 0], 39 mild [HAI = 1], 13 moderate [HAI = 2], and 37 severe CD activity [HAI = 3]. In total, 26 radiologists prospectively scored MRE datasets as per their usual clinical practice. Sensitivity and specificity for active disease [HAI >0] were 83% [95% confidence interval 74% to 90%] and 41% [23% to 61%] for sMARIA, 76% [67% to 84%] and 64% [43% to 80%] for the London score, and 81% [72% to 88%] and 41% [23% to 61%] for the 'extended' London score, respectively. The sMARIA had 84% [69-92%] sensitivity and 53% [41-64%] specificity for severe CD.

CONCLUSIONS

When tested at their proposed cut-offs in a real-world setting, sMARIA, London, and 'extended' London indices achieve high sensitivity for active TI disease against a histological reference standard, but specificity is low.

Simplified Magnetic Resonance Index of Activity Is Useful for Terminal Ileal but not Colonic Disease in Pediatric Crohn Disease

BACKGROUND

Ileocolonoscopy (IC) detects mucosal inflammation and magnetic resonance enterography (MRE) detects transmural inflammation in Crohn disease (CD). We aimed to evaluate the relationship between the simplified magnetic resonance index of activity (MARIAs) and measures of inflammation by IC in children with newly diagnosed CD.

METHODS

Retrospective review of 140 patients 6-18 years of age with CD who had baseline IC and MRE within 5 weeks of diagnosis. MARIAs was calculated for each intestinal segment (terminal ileum [TI], ascending colon, transverse colon, descending colon, sigmoid colon, rectum), defined as (1 × thickness > 3 mm) + (1 × edema) + (1 × fat stranding) + (2 × ulcers). Sensitivity and specificity were derived using receiver operating characteristic (ROC) curves to compare MARIAs to IC findings.

RESULTS

Using IC as the reference standard, the cutoff MARIAs ≥1 identified TI segments with active inflammation with 84% sensitivity, 73% specificity, 85% positive predictive value (PPV), 70% negative predictive value (NPV), and area under the curve (AUC) 0.782 (95% confidence interval [CI] 0.689-0.876). The cutoff MARIAs ≥2 identified TI segments with severe lesions with 87% sensitivity, 76% specificity, 87% PPV, 76% NPV, and AUC 0.814 (95% CI 0.712-0.916). There was poor sensitivity for all colonic segments.

CONCLUSION

The MARIAs is feasible and accurate in reflecting disease activity in the TI, but not in the colon, in children with newly diagnosed CD. Although the MARIAs may be useful for monitoring TI disease activity over time, full assessment continues to require both IC and MRE.

Avoiding contrast-enhanced sequences does not compromise the precision of the simplified MaRIA for the assessment of non-penetrating Crohn's disease activity

OBJECTIVES

Patients with Crohn's disease (CD) require multiple assessments with magnetic resonance enterography (MRE) from a young age. Standard MRE protocols for CD include contrast-enhanced sequences. Gadolinium deposits in brain tissue suggest avoiding gadolinium could benefit patients with CD. This study aimed to compare the accuracy of the simplified Magnetic Resonance Index of Activity (sMaRIA) calculated with and without contrast-enhanced sequences in determining the response to biologic drugs in patients with CD.

METHODS

This post hoc analysis of a prospective study included patients with CD with endoscopic ulceration in ≥ 1 intestinal segment starting biologic drug therapy. Two blinded radiologists used the sMaRIA to score images obtained at baseline and week 46 of treatment first using only unenhanced sequences (T2-sMaRIA) and 1 month later using both unenhanced and enhanced images (CE-sMaRIA). We calculated the rates of agreement between T2-sMaRIA, CE-sMaRIA, and ileocolonoscopy for different conceptualizations of therapeutic response.

RESULTS

A total of 46 patients (median age, 36 years [IQR: 28-47]) were included. Agreement with ileocolonoscopy was similar for CE-sMaRIA and T2-sMaRIA in identifying ulcer healing (kappa = 0.74 [0.55-0.93] and 0.70 [0.5-0.9], respectively), treatment response (kappa = 0.53 [0.28-0.79] and 0.44 [0.17 - 0.71]), and remission (kappa = 0.48 [0.22-0.73] and 0.43 [0.17-0.69]). The standardized effect size was moderate for both CE-sMaRIA = 0.63 [0.41-0.85] p < 0.001 and T2-sMaRIA = 0.58 [0.36-0.80] p < 0.001.

CONCLUSIONS

sMaRIA with and without contrast-enhanced images accurately classified the response according to different therapeutic endpoints determined by ileocolonoscopy.

KEY POINTS

• The simplified Magnetic Resonance Index of Activity is accurate for the assessment of Crohn's disease activity, severity, and therapeutic response, using four dichotomic components that can be evaluated without the need of using contrast-enhanced sequences, representing a practical and safety advantage, but concerns have been expressed as to whether the lack of contrast sequences may compromise precision. • The simplified Magnetic Resonance Index of Activity can assess the response to biologic therapy in patients with Crohn's disease without the need for intravenous contrast agents obtaining comparable results without and with contrast-enhanced sequences. • Avoiding intravenous contrast agents could reduce the duration of the MRE examination and its cost and would increase the acceptance and safety of MRE in clinical research in patients with Crohn's disease.

Can the simplified magnetic resonance index of activity be used to evaluate the degree of activity in Crohn's disease?

Background and aims

A simplified magnetic resonance index of activity (MaRIAs) was recently proposed. Our aim was to verify whether MaRIAs can accurately assess the activity degree of CD.

Methods

We retrospectively analyzed the MRI, ileocolonoscopy, fecal calprotectin (FC), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) data of 93 CD patients. With the SES-CD as the gold standard, MaRIAs’ accuracy, the correlation of MaRIAs and SES-CD, FC, ESR, CRP, and interevaluator reliability were assessed.

Results

MaRIAs ≥ 1 detected segments with active CD with 90.80% specificity and 81.37% sensitivity (area under the curve was 0.91, 95% confidence interval 0.87–0.94). MaRIAs score of 2 or more detected severe lesions with 88.89% specificity and 95.12% sensitivity (AUC was 0.96, 95% confidence interval was 0.94–0.98). The MaRIAs score showed a high correlation with the SES-CD in the terminal ileum, transverse colon, right colon, and left colon (r = 0.85, 0.91, 0.88, 0.86, P < 0.001) and a moderate correlation with the SES-CD in the rectum (r = 0.74, P < 0.001). The global MaRIAs score was highly correlated with the global SES-CD (r = 0.90, P < 0.001). The global MaRIAs score was positively correlated with the fecal calprotectin (FC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) (r = 0.77, r = 0.64, and r = 0.68). The intragroup correlation coefficient (ICC) of the two physicians was nice in the terminal ileum, the right colon, the transverse colon, the left colon and was moderately good in the rectum.

Conclusion

MaRIAs can accurately evaluate the disease activity level of CD and are highly correlated with SES-CD and biomarkers. The interrater reliability of the two physicians was moderately good to nice.

Magnetic resonance enterography in Crohn's disease patients: current state of the art and future perspectives

INTRODUCTION

Crohn's disease (CD) is a major concern due to relatively high incidence and major complications like stricture or fistulas, often requiring surgical treatment. In recent years, magnetic resonance enterography (MRE) became a popular method of diagnosis and disease surveillance. The purpose of this review is to summarize and discuss the major and most recent advances in various aspects of MRE usage in diagnosong Crohn's disease, and to discuss advances in technique, disease activity monitoring and response to treatment.

METHODS

A literature search was performed and relevant publications were included, with emphasis on articles from the past decade.

AREAS COVERED

In this review we have presented articles with major advances in the field of MRE of CD patients such as proper sequence selection, recent advances in scoring of disease activity, differentiation between inflammation and fibrosis, response to treatment and technological advances such as the use of AI.

EXPERT OPINION

The main goal in improving MRE performance will be sequence selection aimed at differenting between inflammation and stricture while shortening the study length adjusted to patient compliance, and developing a standardized scoring system for MRE reporting assisted by artificial intelligence.

Hepatic mosaic enhancement pattern correlates with increased inflammatory activity and adverse therapeutic outcomes in patients with Crohn's disease

PURPOSE

This study aimed to evaluate the role of hepatic mosaic enhancement pattern (HMEP) on computed tomography images in the disease activity and therapeutic outcome of Crohn's Disease (CD).

METHODS

Twenty-five CD patients with HMEP comprised the HMEP group, and 25 CD patients without HMEP, who had a similar onset age, sex, and disease course with those in the HMEP group, comprised the non-HMEP group. No underlying liver/biliary disease was observed in any of the patients. Clinical characteristics, laboratory test results, Lémann index, and CD endoscopic index of severity (CDEIS) were compared between the groups using the Student t-, Mann-Whitney U, Chi square, or Fisher's exact tests. Patients received top-down, step-up, or traditional treatment during the follow-up period. After the 1-year follow-up, therapeutic outcomes (active inflammation [CDEIS > 3.5 if the endoscopic data were available, or C-reactive protein level > 5 mg/L if the endoscopic data were unavailable] or remission) were evaluated.

RESULTS

The occurrence rate of fistulas/abscesses was higher in the HMEP group (84%, 21/25) than in the non-HMEP group (48%, 12/25) with no statistical significance (P = 0.056). The HMEP group showed a higher C-reactive protein level (P = 0.001), erythrocyte sedimentation rate (P = 0.013), and blood platelet count (P = 0.005). There was no significant difference in therapeutic strategies between the groups (P = 0.509). The HMEP group showed a significantly lower remission ratio after anti-inflammatory treatment than the non-HMEP group (P = 0.045).

CONCLUSIONS

HMEP was correlated with increased inflammatory activity and adverse therapeutic outcomes in CD. This finding provided insights regarding novel markers of CD diagnosis and treatment.

MRE Evaluation of Intestinal Inflammation: Qualitative and Quantitative Assessment

ABSTRACT

Magnetic resonance enterography (MRE) is a powerful tool for evaluation and management of patients with Crohn disease. Changes of active inflammation of the small bowel can reliably and reproducibly be detected and monitored. Findings indicative of active inflammation include bowel wall thickening, intramural edema and mural hyperenhancement. These changes are most commonly reported qualitatively; however, quantitative indices have also been developed and validated to measure and monitor inflammation both for clinical care and research purposes. This article describes the essential findings of active inflammation on MRE as well as the fundamentals of both qualitative and quantitative assessment and reporting.

Pre-treatment magnetic resonance enterography findings predict the response to TNF-alpha inhibitors in Crohn's disease

BACKGROUND

Identifying predictors of therapeutic response is the cornerstone of personalised medicine.

AIM

To identify predictors of long-term healing of severe inflammatory lesions based on magnetic resonance enterography (MRE) findings in patients with Crohn's disease (CD) treated with tumour necrosis factor alpha (TNF-α) inhibitors.

METHODS

This prospective longitudinal single-centre study included patients with clinically active CD requiring treatment with TNF-α inhibitors with at least one intestinal segment with a severe inflammatory lesion detected by MRE (segmental MaRIA ≥11). MRE data were obtained at baseline, and at weeks 14 and 46. The primary endpoint was healing of severe inflammatory lesions (MaRIA <11) in each segment. The secondary endpoint was healing of all severe inflammatory lesions on a per-patient analysis.

RESULTS

We included 58 patients with 86 intestinal segments with severe inflammatory lesions. At week 46, healing of severe lesions was found in 51/86 (59.3%) segments, and complete healing of inflammatory lesions in all segments was found in 28/58 (48.6%) patients. Multivariable analysis found baseline-negative predictors of long-term healing of severe inflammation were ileal (as opposed to colonic) location (OR 0.00, [0.00-0.56] P = 0.002) and presence of creeping fat on MRE (OR 0.00 [0.00-0.57]; P = 0.001). Persistence of segmental MaRIA score >10.6 at week 14 was a negative predictor of healing at week 46 (OR 0.3 [0.04--0.38]; P < 0.001).

CONCLUSION

In patients with CD, the absence of creeping fat detected at baseline MRE and location of severe inflammatory lesions are clinically relevant predictors of long-term healing of severe inflammation under treatment with TNF-α inhibitors.

The new simplified MARIA score applies beyond clinical trials: A suitable clinical practice tool for Crohn's disease that parallels a simple endoscopic index and fecal calprotectin

BACKGROUND

A simplified magnetic resonance enterography (MRe) index (sMARIA) for Crohn's disease (CD) was recently developed and validated.

OBJECTIVE

Our aims were (a) to assess sMARIA's accuracy in a sample other than the validation cohort; (b) to evaluate its correlation with a simpler endoscopy index (SES-CD) and fecal calprotectin (FC); and (c) to assess the need of an expert radiologist to reliably use sMARIA.

METHODS

Patients with CD who underwent MRe, ileocolonoscopy and FC within 2-4 weeks had their MRe retrospectively reviewed by two blinded raters. Disease activity was evaluated through sMARIA, SES-CD and FC. sMARIA's accuracy, indices correlation, and interrater reliability were assessed.

RESULTS

In total, 84 patients were included, comprising 420 intestinal segments evaluations. sMARIA ≥1 accurately identified segments with active disease (90% sensitivity, 98% specificity; area under the curve 0.94, 95% confidence interval (CI) 0.91-0.97; p < 0.01). sMARIA correlated with endoscopy, both for ileal and colonic segments (R = 0.94 and R = 0.82; p < 0.01). Per patient, there was a strong correlation between sMARIA, endoscopy (R = 0.95; p < 0.01) and FC (R = 0.91; p < 0.01). Interrater agreement was excellent (intraclass correlation coefficient 0.95; 95% CI 0.94-0.96; p < 0.01).

CONCLUSION

sMARIA accurately measured CD activity using SES-CD as standard of reference, and exhibited high correlation with a simple endoscopic index and a biomarker. The interrater reliability between a radiology resident and an expert was excellent.