Accuracy of Diffusion-weighted Magnetic Resonance Imaging in Detecting Mucosal Healing and Treatment Response, and in Predicting Surgery, in Crohn's Disease

AI-luminating Artificial Intelligence in Inflammatory Bowel Diseases: A Narrative Review on the Role of AI in Endoscopy, Histology, and Imaging for IBD

Endoscopy, histology, and cross-sectional imaging serve as fundamental pillars in the detection, monitoring, and prognostication of inflammatory bowel disease (IBD). However, interpretation of these studies often relies on subjective human judgment, which can lead to delays, intra- and interobserver variability, and potential diagnostic discrepancies. With the rising incidence of IBD globally coupled with the exponential digitization of these data, there is a growing demand for innovative approaches to streamline diagnosis and elevate clinical decision-making. In this context, artificial intelligence (AI) technologies emerge as a timely solution to address the evolving challenges in IBD. Early studies using deep learning and radiomics approaches for endoscopy, histology, and imaging in IBD have demonstrated promising results for using AI to detect, diagnose, characterize, phenotype, and prognosticate IBD. Nonetheless, the available literature has inherent limitations and knowledge gaps that need to be addressed before AI can transition into a mainstream clinical tool for IBD. To better understand the potential value of integrating AI in IBD, we review the available literature to summarize our current understanding and identify gaps in knowledge to inform future investigations.

Current Approaches for Monitoring of Patients with Inflammatory Bowel Diseases: A Narrative Review

BACKGROUND

Patients with inflammatory bowel diseases (IBD) require proactive monitoring both during the active phase to evaluate therapeutic response and during the remission phase to evaluate relapse or colorectal cancer surveillance. However, monitoring may vary between patients with ulcerative colitis (UC) and Crohn's disease (CD), with distinct tools and intervals.

METHODS

This narrative review aims to focus on modern approaches to IBD monitoring, considering international guidelines and expert consensus.

RESULTS

The most recent European diagnostic guidelines advocate a combination of clinical, laboratory, endoscopic, and radiological parameters to evaluate the disease course of patients with IBD. Unfortunately, the conventional symptom-based therapeutic approach does not improve long-term outcomes and there is no single ideal biomarker available. Endoscopy plays a key role in evaluating response to therapy as well as monitoring disease activity. Recently, bedside intestinal ultrasound (IUS) has gained increasing interest and diffusion as it appears to offer several advantages including the monitoring of therapeutic response.

CONCLUSION

In light of growing clinical advances, we present a schematic evidence-based monitoring algorithm that can be easily applied in clinical practice which combines all major monitoring modalities, including noninvasive tools such as IUS and video-capsule endoscopy.

Early Intestinal Ultrasound Predicts Long-Term Endoscopic Response to Biologics in Ulcerative Colitis

BACKGROUND AND AIMS

The Milan ultrasound criteria [MUC] is a validated score to assess endoscopic activity in ulcerative colitis [UC]. MUC > 6.2 detects Mayo endoscopic score [MES] > 1. In this study we evaluated the predictive value of MUC for biologic treatment response, using colonoscopy [CS] as a reference standard.

METHODS

Consecutive UC patients starting biologic therapy were included, and underwent CS, IUS, clinical assessment and faecal calprotectin [FC] measurement at baseline and within 1 year. In addition, IUS, clinical and FC assessments were performed at week 12. The primary objective was to evaluate whether ultrasound improvement [MUC ≤ 6.2] at week 12 predicted endoscopic improvement at reassessment [MES ≤ 1]. Endoscopic remission was defined as MES = 0.

RESULTS

Forty-nine patients were included [59% under infliximab, 29% under vedolizumab, 8% under adalimumab, 4% under ustekinumab]. MUC ≤ 6.2 at week 12 was the only independent predictor for MES ≤ 1 and MES = 0 at reassessment (odds ratio [OR] 5.80, p = 0.010; OR 10.41, p = 0.041; respectively). MUC ≤ 6.2 at week 12 showed a negative predictive value of 96% for detecting MES = 0. A ≥2 reduction of the MUC predicted MES = 0 (area under the curve [AUC] 0.816). MUC ≤ 4.3 was the most accurate cut-off value for MES = 0 [AUC 0.876]. Guyatt's responsiveness ratio for the MUC was 1.73 [>0.8].

CONCLUSION

MUC ≤ 6.2 at week 12 predicts long-term endoscopic response. MUC is accurate in monitoring treatment response and may be used in both clinical trials and routine practice.

Predicting Treatment Response in Inflammatory Bowel Diseases: Cross-Sectional Imaging Markers

Therapeutic options for inflammatory bowel diseases (IBD) have largely expanded in the last decades, both in Crohn's disease and ulcerative colitis, including multiple biological drugs targeting different inflammation pathways. However, choosing the best treatment and timing for each patient is still an undeniable challenge for IBD physicians due to the marked heterogeneity among patients and disease behavior. Therefore, early prediction of the response to biological drugs becomes of utmost importance, allowing prompt optimization of therapeutic strategies and thus paving the way towards precision medicine. In such a context, researchers have recently focused on cross-sectional imaging techniques (intestinal ultrasound, computed tomography, and magnetic resonance enterography) in order to identify predictive markers of response or non-response to biologic therapies. In this review, we aim to summarize data about imaging factors that may early predict disease behavior during biological treatment, potentially helping to define more precise and patient-tailored strategies.

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.

Role of Cross-Sectional Imaging in Pediatric Inflammatory Bowel Disease

BACKGROUND

The association between radiological remission and natural history of disease in children with inflammatory bowel diseases (IBD) is poorly known.

AIMS

(i) To assess the correlation between cross-sectional imaging (CSI) (ultrasound and magnetic resonance imaging) and clinical, biomarker and endoscopic disease activity; (ii) to evaluate the impact of radiological activity on the occurrence of complications in pediatric patients with IBD.

METHODS

A retrospective study including pediatric patients with IBD and radiological follow-up of at least one year was conducted between 2003 and 2019 at the Nancy University Hospital.

RESULTS

In total, 118 patients (66 Crohn's disease (CD) and 52 ulcerative colitis (UC)) were included. Median follow-up duration was 5.2 years (range: 1.1-15.4). Seventeen (25.8%) patients with CD and 7 (13.5%) patients with UC achieved and maintained radiological remission until last follow-up. No IBD patient achieving radiological remission experienced complications or relapse. In patients not achieving radiologic remission, complications and surgery occurred in 13/49 (26.5%) and 8/49 (16.3%) patients with CD and in 5/45 (11.1%) and 5 (11.1%) subjects with UC. Among patients with CD, the association for remission status between radiological and endoscopic assessment was excellent (Cramer's V test (V) = 0.50), and moderate between radiological and either clinical (V = 0.30) or biochemical (V = 0.33) assessments. In UC, the association for remission status between radiological and either endoscopic or clinical assessments were weak (V = 0.19 and V = 0.20 respectively), and moderate (V = 0.23) between radiological and biochemical assessments.

CONCLUSION

CSI may replace endoscopic monitoring in pediatric CD. Radiological remission status predicts long-term disease outcomes.

Disease Monitoring in Inflammatory Bowel Disease: Evolving Principles and Possibilities

Inflammatory bowel disease is a progressive and debilitating condition. Early and effective treatment using a treat-to-target approach is key to improving patient outcomes. Therefore, proactive monitoring is essential to ensure that treatment strategies are working and targets are being met. In this review we discuss the current monitoring tools available to us and how they can be used. We also discuss the importance of monitoring during key phases of the disease and propose an optimum treat-to-target monitoring strategy for Crohn's disease and ulcerative colitis. Regarding the advent of new technology, we discuss how this may improve our monitoring capabilities and how we envisage future monitoring strategies of inflammatory bowel diseases.

Bowel ultrasound score is accurate in assessing response to therapy in patients with Crohn's disease

BACKGROUND

We developed a non-invasive bowel ultrasound score (BUSS) to assess disease activity in Crohn's disease (CD). BUSS >3.52 is an indicator of endoscopic activity (SES-CD>2).

AIM

To assess whether BUSS, in addition to detecting inflammatory lesions, also detects relevant changes of these lesions over time.

METHODS

This was a prospective observational study of 49 patients with active CD. All patients underwent bowel ultrasound and colonoscopy at baseline and at re-assessment after treatment with biologics and/or immunosuppressants. The primary objective was to assess the sensitivity to change of BUSS in patients treated for active CD, using the SES-CD as reference standard.

RESULTS

BUSS changed significantly from baseline to re-assessment in patients achieving endoscopic response (a reduction of SES-CD of at least 50% vs baseline: 4.87 [3.78-6.0] vs 2.47 [2.25-3.36], P < 0.001) and endoscopic remission (SES-CD ≤ 2: 4.65 [3.58-6.03] vs 2.25 [2.25-3.46], P = 0.003). A change of -1.2 in BUSS over time predicted endoscopic response (AUC 0.786, 95% CI 0.645-0.890; sensitivity 74%, specificity 83%). BUSS determined endoscopic response with 80% accuracy, and endoscopic remission with 78% accuracy. BUSS accurately detected changes in lesion severity (Guyatt score: 1.41 and standardized effect score: 1.74). BUSS did not change significantly in patients who did not achieve endoscopic response (5.62 [5.26-6.15] vs 5.70 [4.97-6.19], P = 0.53) or endoscopic remission (5.62 [5.18-6.14] vs 5.10 [4.58-6.05]; P = 0.10).

CONCLUSION

BUSS is sensitive to change in CD.

Cross-Sectional Imaging Instead of Colonoscopy in Inflammatory Bowel Diseases: Lights and Shadows

International guidelines recommend a treat-to-target strategy with a close monitoring of disease activity and therapeutic response in inflammatory bowel diseases (IBD). Colonoscopy (CS) represents the current first-line procedure for evaluating disease activity in IBD. However, as it is expensive, invasive and poorly accepted by patients, CS is not appropriate for frequent and repetitive reassessments of disease activity. Recently, cross-sectional imaging techniques have been increasingly shown as reliable tools for assessing IBD activity. While computed tomography (CT) is hampered by radiation risks, routine implementation of magnetic resonance enterography (MRE) for close monitoring is limited by its costs, low availability and long examination time. Novel magnetic resonance imaging (MRI)-based techniques, such as diffusion-weighted imaging (DWI), can overcome some of these weaknesses and have been shown as valuable options for IBD monitoring. Bowel ultrasound (BUS) is a noninvasive, highly available, cheap, and well accepted procedure that has been demonstrated to be as accurate as CS and MRE for assessing and monitoring disease activity in IBD. Furthermore, as BUS can be quickly performed at the point-of-care, it allows for real-time clinical decision making. This review summarizes the current evidence on the use of cross-sectional imaging techniques as cost-effective, noninvasive and reliable alternatives to CS for monitoring patients with IBD.

Is the Mixed Use of Magnetic Resonance Enterography and Computed Tomography Enterography Adequate for Routine Periodic Follow-Up of Bowel Inflammation in Patients with Crohn's Disease?

OBJECTIVE

Computed tomography enterography (CTE) and magnetic resonance enterography (MRE) are considered substitutes for each other for evaluating Crohn's disease (CD). However, the adequacy of mixing them for routine periodic follow-up for CD has not been established. This study aimed to compare MRE alone with the mixed use of CTE and MRE for the periodic follow-up of small bowel inflammation in patients with CD.

MATERIALS AND METHODS

We retrospectively compared two non-randomized groups, each comprising 96 patients with CD. One group underwent CTE and MRE (MRE followed by CTE or vice versa) for the follow-up of CD (interval, 13-27 months [median, 22 months]), and the other group underwent MRE alone (interval, 15-26 months [median, 21 months]). However, these two groups were similar in clinical characteristics. Three independent readers from three different institutions determined whether inflammation had decreased, remained unchanged, or increased within the entire small bowel and the terminal ileum based on sequential enterography of the patients after appropriate blinding. We compared the two groups for inter-reader agreement and accuracy (terminal ileum only) using endoscopy as the reference standard for enterographic interpretation.

RESULTS

The inter-reader agreement was greater in the MRE alone group for the entire small bowel (intraclass correlation coefficient [ICC]: 0.683 vs. 0.473; p = 0.005) and the terminal ileum (ICC: 0.656 vs. 0.490; p = 0.030). The interpretation accuracy was higher in the MRE alone group without statistical significance (70.9%-74.5% vs. 57.9%-64.9% in individual readers; adjusted odds ratio = 3.21; p = 0.077).

CONCLUSION

The mixed use of CTE and MRE was inferior to MRE alone in terms of inter-reader reliability and could probably be less accurate than MRE alone for routine monitoring of small bowel inflammation in patients with CD. Therefore, the consistent use of MRE is favored for this purpose.

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

Endoscopy is the gold standard for objective assessment of colonic disease activity in inflammatory bowel disease (IBD). Non-invasive colonic imaging using bowel ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) may have a role in quantifying colonic disease activity. We reviewed the diagnostic accuracy of these modalities for assessment of endoscopically or histopathologically defined colonic disease activity in IBD. We searched Embase, MEDLINE, and the Web of Science from inception to 20 September 2021. QUADAS-2 was used to evaluate the studies' quality. A meta-analysis was performed using a bivariate model approach separately for MRI and US studies only, and summary receiver operating characteristic (ROC) curves were obtained. CT studies were excluded due to the absence of diagnostic test data. Thirty-seven studies were included. The mean sensitivity and specificity for MRI studies was 0.75 and 0.91, respectively, while for US studies it was 0.82 and 0.90, respectively. The area under the ROC curves (AUC) was 0.88 (95% CI, 0.82 to 0.93) for MRI, and 0.90 (95% CI, 0.75 to 1.00) for US. Both MRI and US show high diagnostic accuracy in the assessment of colonic disease activity in IBD patients.

Diagnosis of postoperative recurrence of Crohn disease with MR-enterography: Value of diffusion-weighted imaging

PURPOSE

To compare the diagnostic capabilities of MR enterography (MRE) using contrast-enhanced (CE) sequences with those of MRE using diffusion-weighted (DW) imaging for the diagnosis of postoperative recurrence at the neo-terminal ileum and/or anastomosis after ileocolonic resection in patients with Crohn disease (CD), and to clarify the role of additional DW imaging to CE-MRE in this context.

MATERIAL AND METHODS

Forty patients who underwent ileal resection for CD, and both endoscopy and MRE within the first year after surgery were included. There were 21 men and 19 women, with a mean age of 38 years±12 (SD) years (range: 18-67 years). MRE examinations were blindly analyzed independently by one senior (R1) and one junior (R2) radiologist for the presence of small bowel postoperative recurrence at the anastomotic site. During a first reading session, T2-, steady-state- and DW-MRE were reviewed (DW-MRE or set 1). During a separate distant session, T2-, steady-state- and CE-MRE were reviewed (CE-MRE or set 2). Lastly, all sequences were analyzed altogether (set 3). Performances of each reader for the diagnosis of postoperative recurrence were evaluated using endoscopic findings as the standard of reference (Rutgeerts score≥i2b).

RESULTS

Fifteen patients out of 40 (37.5%) had endoscopic postoperative recurrence at the anastomotic site. Sensitivity for the diagnosis of postoperative recurrence was 73% (95% CI: 51-96%) for R1 and 67% (95% CI: 43-91%) for R2 using set 1, and 80% (95% CI: 60-100%) for both readers using set 2. There was no significant differences in sensitivity between reading set 1 and reading set 2, for either R1 or R2 (R1, P> 0.99; R2, P=0.48). Specificity was 96% (95% CI: 88-100%) for both readers using set 1 or using set 2. Reading set 3 yielded an area under the ROC curve (AUC) of 0.93 (95% CI: 0.84-1) versus 0.89 (95% CI: 0.75-1) with set 1 (P=0.18) and versus 0.89 (95% CI: 0.78-1) with set 2 (P=0.21). No significant differences in AUC were found between set 1 or 2 and set 3 (P=0.18), nor between set 1 and 2 (P=0.76). Accuracies were 88% (95% CI: 74-95%) and 85% (95% CI: 71-93%) for DW-MRE for R1 and R2, respectively; 90% (95% CI: 77-96%) for CE-MRE for both readers; and 93% (95% CI: 80-97%) and 88% (95% CI: 74-95%) for R1 and R2 with set 3, respectively.

CONCLUSION

DW-MRE has diagnostic capabilities similar to those of CE-MRE for the diagnosis of postoperative recurrence of CD at the anastomotic site.

Emerging Imaging Biomarkers in Crohn Disease

ABSTRACT

In this review article, we present the latest developments in quantitative imaging biomarkers based on magnetic resonance imaging (MRI), applied to the diagnosis, assessment of response to therapy, and assessment of prognosis of Crohn disease. We also discuss the biomarkers' limitations and future prospects. We performed a literature search of clinical and translational research in Crohn disease using diffusion-weighted MRI (DWI-MRI), dynamic contrast-enhanced MRI (DCE-MRI), motility MRI, and magnetization transfer MRI, as well as emerging topics such as T1 mapping, radiomics, and artificial intelligence. These techniques are integrated in and combined with qualitative image assessment of magnetic resonance enterography (MRE) examinations. Quantitative MRI biomarkers add value to MRE qualitative assessment, achieving substantial diagnostic performance (area under receiver-operating curve = 0.8-0.95). The studies reviewed show that the combination of multiple MRI sequences in a multiparametric quantitative fashion provides rich information that may help for better diagnosis, assessment of severity, prognostication, and assessment of response to biological treatment. However, the addition of quantitative sequences to MRE examinations has potential drawbacks, including increased scan time and the need for further validation before being used in therapeutic drug trials as well as the clinic.

Relevance of monitoring transmural disease activity in patients with Crohn's disease: current status and future perspectives

Treatment targets of inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn's disease (CD) have evolved over the last decade. Goals of therapy consisting of symptom control and steroid sparing have shifted to control of disease activity with endoscopic remission being an important endpoint. Unfortunately, this requires ileocolonoscopy, an invasive procedure. Biomarkers [C-reactive protein (CRP) and fecal calprotectin (FCP)] have emerged as surrogates for endoscopic remission and disease activity, but also have limitations. Despite this evolution, we must not lose sight that CD involves transmural inflammation, not fully appreciated with ileocolonoscopy. Therefore, transmural assessment of disease activity by cross-sectional imaging, in particular with magnetic resonance enterography (MRE) and intestinal ultrasonography (IUS), is vital to fully understand disease control. Bowel-wall thickness (BWT) is the cornerstone in assessment of transmural inflammation and BWT normalization, with or without bloodflow normalization, the key element demonstrating resolution of transmural inflammation, namely transmural healing (TH) or transmural remission (TR). In small studies, achievement of TR has been associated with improved long-term clinical outcomes, including reduced hospitalization, surgery, escalation of treatment, and a decrease in clinical relapse over endoscopic remission alone. This review will focus on the existing literature investigating the concept of TR or residual transmural disease and its relation to other existing treatment targets. Current data suggest that TR may be the next logical step in the evolution of treatment targets.

Serum 1,3-beta-D-glucan as a noninvasive test to predict histologic activity in patients with inflammatory bowel disease

BACKGROUND

1,3-beta-D-glucan (BG) is a ubiquitous cell wall component of gut micro-organisms. We hypothesized that the serum levels of BG could reflect active intestinal inflammation in patients with inflammatory bowel disease.

AIM

To determine whether the serum BG concentrations correlate with intestinal inflammation.

METHODS

A prospective observational study was performed in a tertiary referral center, from 2016 to 2019, in which serum BG was determined in 115 patients with Crohn’s disease (CD), 51 with ulcerative colitis (UC), and 82 controls using a photometric detection kit. Inflammatory activity was determined by ileocolonoscopy, histopathology, magnetic resonance enterography, and biomarkers, including fecal calprotectin (FC), C-reactive protein, and a panel of cytokines. The ability of BG to detect active vs inactive disease was assessed using the area under the receiver operating characteristic curve. In subgroup analysis, serial BG was used to assess the response to therapeutic interventions.

RESULTS

The serum BG levels were higher in CD patients than in controls (P = 0.0001). The BG levels paralleled the endoscopic activity in CD patients and histologic activity and combined endoscopic and histologic activity in both CD and UC patients. The area under the curve (AUC) in receiver operating characteristic analysis to predict endoscopic activity was 0.694 [95% confidence interval (CI): 0.60-0.79; P = 0.001] in CD, and 0.662 (95%CI: 0.51-0.81; P = 0.066) in UC patients. The AUC in receiver operating characteristic analysis to predict histologic activity was 0.860 (95%CI: 0.77-0.95; P < 0.001) in CD, and 0.786 (95%CI: 0.57-0.99; P = 0.015) in UC patients. The cut-off values of BG for both endoscopic and histologic activity were 60 µg/mL in CD, and 40 µg/mL in UC patients. Performance analysis showed that the results based on BG of 40 and 60 µg/mL were more specific for predicting endoscopic activity (71.8% and 87.2% for CD; and 87.5% and 87.5% for UC, respectively) than FC (53.3% and 66.7% for CD; and 20% and 80% for UC, respectively); and also histologic activity (60.5% and 76.3% for CD; and 90.0% and 95.0% for UC, respectively) than FC (41.7% and 50.0% for CD; and 25% and 50% for UC, respectively). Regarding the clinical, endoscopic, and histologic activities, the BG levels were reduced following therapeutic intervention in patients with CD (P < 0.0001) and UC (P = 0.003). Compared with endoscopic (AUC: 0.693; P = 0.002) and histologic (AUC: 0.868; P < 0.001) activity, no significant correlation was found between serum BG and transmural healing based on magnetic resonance enterography (AUC: 0.576; P = 0.192). Positive correlations were detected between BG and IL-17 in the CD (r: 0.737; P = 0.001) and the UC group (r: 0.574; P = 0.005), and between BG and interferon-gamma in the CD group (r: 0.597; P = 0.015).

CONCLUSION

Serum BG may represent an important novel noninvasive approach for detecting mucosal inflammation and therapeutically monitoring inflammatory bowel diseases, particularly in CD.

Treat-to-target approach in the management of inflammatory Bowel disease

With the advent of biologic and small molecule therapies, there has been a substantial change in the treatment of inflammatory bowel disease. These advances have had a great impact in preventing disease progression, intestinal damage and, therefore, have contributed to a better quality of life. Discordance between symptom control and mucosal healing has been demonstrated. This has led to the search for new disease control targets. The treat to target strategy, based on expert recommendations and now a randomized controlled trial, has determined that clinical and endoscopic remission should be the goal of therapy. Biomarkers (fecal calprotectin) can be a surrogate target. Although histological healing has shown benefits, there is inadequate evidence and inadequate therapy for that to be a fixed goal at this time. This review will focus on therapeutic goals, according to the evidence currently available, and evaluate strategies to achieve them.

Targeting the gut layers in Crohn's disease: mucosal or transmural healing?

INTRODUCTION

Although the landmark of Crohn's Disease (CD) is the transmural inflammation, mucosal healing (MH), which is assessed by colonoscopy, is currently the gold standard of CD management. Transmural healing (TH) is a new concept evaluated by cross-sectional imaging (CSI) techniques, such as bowel ultrasound (US), computed tomography enterography (CTE), and magnetic resonance enterography (MRE). Little is known about the clinical significance of persisting mural disease and the predictive value of complete TH.

AREAS COVERED

The authors reviewed the available literature on TH and its meaning as predictor of long-term outcomes in CD, to explore if TH may be a better target compared to MH in CD patients, in terms of disease outcome, such as medication changes, hospitalization, or surgery.

EXPERT OPINION

Some evidence suggests that achieving TH has a predictive value in CD management and correlates with better disease outcome than MH, although existing studies are few and with limitations. A definitive definition of TH is not yet established and the frequency or the preferred modality of TH evaluation remains unclear. Implementing TH in treat-to-target approach may enable stricter disease monitoring with noninvasive methods and finally change the disease course, preventing irreversible bowel damage.

Flare-IBD: development and validation of a questionnaire based on patients' messages on an internet forum for early detection of flare in inflammatory bowel disease: study protocol

INTRODUCTION

Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease (IBD), are chronic disabling conditions characterised by flares followed by periods of remission. However, patients with IBD are seen every 3-6 months in the outpatient clinic, and the occurrence of a flare between two outpatient visits is not captured. To our knowledge, there is no validated patient-reported outcome (PRO) tool to measure the phenomenon of flare in IBD. This study aimed to use an innovative methodology to collect messages posted by patients in an internet forum for developing and validating a PRO measuring flare in IBD.

METHODS AND ANALYSIS

The design involves (1) computer engineering sciences for scraping extraction of messages posted in an internet forum and for identification of messages related to flare; (2) qualitative methods for thematic content analyse of the messages posted, for candidate items generation, for items selection (Delphi process) and for items adjustment ('think-aloud' interviews) and (3) quantitative methods for psychometric validation of the PRO.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Comité de Protection des Personnes (CPP) CPP Nord-Ouest I (19.07.15.44139) in November 2019. The project aims to provide a tool to evaluate IBD flare in current medical practice that is constructed with patients' perspectives. Items generation from a source corresponding to exchanges in an internet forum is an innovative method in this field and provides a wider coverage of qualitative data. If such a forum can result in interesting material, then this could be a new methodological perspective for generating items for questionnaires. Findings will be reported and disseminated widely through international peer-reviewed journal publications, oral and poster presentations at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04180345.

Which MRI Score and Technique Should Be Used for Assessing Crohn's Disease Activity?

Magnetic resonance (MR) enterography is assuming an increasingly important and central role in the management of patients with Crohn’s disease, as it is not only involved in diagnosis and staging of the disease but also allows for patients’ follow-up, evaluating the response to therapy, and predicting disease outcomes. Several MR scores have been developed but unfortunately there is no globally accepted score. The most widely used scores are the Magnetic Resonance Index of Activity (MaRIA) score, the London score, the Nancy score, and the Clermont score; however, there are multiple differences between these tools in terms of the assessed radiological items, fasting, administration of oral or intravenous contrast, and the use of diffusion-weighted images. Here we reviewed the main characteristics of each MR scoring system to clarify which is the most appropriate score for monitoring disease activity in both clinical practice and clinical trials.

Use of Cross-Sectional Imaging for Tight Monitoring of Inflammatory Bowel Diseases

A treat-to-target strategy with close monitoring of intestinal inflammation is recommended in inflammatory bowel disease (IBD). Ileocolonoscopy remains the gold standard for assessing disease activity in IBD but is a relatively invasive procedure and is impossible to repeat in the context of tight monitoring strategies. In addition to biomarkers, cross-sectional imaging increasingly is used in these patients. Computed tomography is limited by the use of radiation, while the use of magnetic resonance enterography (MRE) is limited by its cost and access. There is growing interest in bowel ultrasound that represents a cost-effective, noninvasive, and well-tolerated modality in clinical practice, but it is operator dependent. Compared with ileocolonoscopy and MRE, bowel US has been shown to have the same level of accuracy in assessing and monitoring disease activity for both CD and UC and thus can be considered a point-of-care test. Diffusion-weighted imaging (DWI) is a MR imaging technique that increasingly is used in both IBD and non-IBD conditions and has been shown to be a valuable and accurate tool for assessing and monitoring IBD activity. Compared with conventional MRE, DWI is quicker, less time consuming, may not require intravenous contrast agent, fasting, bowel cleansing, oral preparation, or rectal preparation. This review discusses the role of these cross-sectional imaging techniques for the management of patients with IBD. In the near future, the value of DWI and ultrasound in assessing IBD will require further investigation in the era of transmural healing in CD and complete mucosal healing, including histologic remission, in ulcerative colitis.

Evolving therapeutic goals in Crohn's disease management

The main objectives in Crohn's disease are to avoid disease complications and preserve the patient's quality of life. Early disease control and close monitoring with specific targets to reach might be the only way to change the disease course. In two decades, we have moved from clinical response to full remission (clinical and endoscopic remission) requiring a tight monitoring of both symptoms and objective signs of inflammation. This review summarizes the concepts of tight control and treat-to-target and their potential for disease modification.

Evolving primary and secondary endpoints in randomized controlled trials leading to approval of biologics and small molecules in IBD: an historical perspective

Introduction: Therapeutic goals in inflammatory bowel diseases (IBD) have evolved, over the last decades, from clinical response to complete remission (clinical and endoscopic remission).Areas covered: Development of biologics and small molecules has been associated with the development of new endpoints in IBD trials that could not have been achieved in the pre-biologics era. Herein, we focus on evolving endpoints for approved biologics and small molecules. We searched for relevant publications using Medline/PubMed, Embase and the Cochrane Library from their inception to 1 July 2019.Expert opinion: Endpoints differ between induction (clinical and endoscopic response) and maintenance trials (clinical and endoscopic remission) because the goal is to evaluate the anti-inflammatory effect of a given drug during induction, whereas full disease control is the ultimate goal during the maintenance phase in order to change patients' life and disease course. Histological healing has recently emerged as a new co-primary endpoint in ulcerative colitis, and is now part of the definition of mucosal healing in these trials. Whether new endpoints such as transmural and radiologic healing could become an endpoint and replace endoscopy in Crohn's disease trials in the near future requires further investigation.

The Role of the Radiologist in Determining Disease Severity in Inflammatory Bowel Diseases

Crohn's disease and ulcerative colitis are chronic inflammatory diseases that lead to progressive bowel damage including the development of stricturing and penetrating complications. Increasingly, cross-sectional imaging with computed tomography or magnetic resonance scans have emerged as leading tools to: (1) assess disease activity; (2) monitor response to therapy or disease recurrence; and (3) identify disease-related complications. Several validated radiological scoring systems have been developed to quantify cross-sectional and longitudinal inflammatory burden in these diseases and to monitor response to treatment. Bowel ultrasound is also a simple and inexpensive tool but is operator dependent in its performance.

"Can Magnetic Resonance Enterography (MRE) replace ileo-colonoscopy for evaluating disease activity in Crohn's disease?"

Crohn's disease is a form of chronic inflammatory bowel disease that can lead to structural bowel damage due to transmural inflammation. Ileo-colonosocopy is currently essential for initial diagnosis. Reassessment of disease burden is frequently needed during episodes of active disease and when evaluating treatment efficacy. This review compares the role of Magnetic Resonance Enterography (MRE) and ileocolonoscopy in Crohn's disease management and whether cross-sectional imaging can replace invasive endoscopic tests. MRE can give information on the small bowel not visible at ileo-colonoscopy, and on extra-luminal complications. Evaluation of the bowel by MRE allows assessment of the submucosa and serosa, and thus transmural healing. MRE offers a well tolerated investigation and additional information on disease activity to better manage patients with Crohn's disease. Increasingly, there are a range of newer techniques such as diffusion weighted imaging, magnetisation transfer and motility MRI which provide greater information on fibrosis and predictors to treatment response which has been lacking despite the use of ileo-colonoscopy for several decades.