Bettenworth, Dominik

Abstract Background Colonic strictures in Crohn’s disease (CD) present a complex and relatively underexplored clinical issue. Imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), and intestinal ultrasound (IUS), have established criteria for evaluating small bowel CD strictures. However, radiologic definitions of benign colonic strictures and their diagnostic accuracy are not well-developed. Endoscopic definitions of colonic strictures are the most well-described. We conducted a systematic review to summarize definitions, diagnosis, and identification of inflammation and fibrosis of colonic strictures on endoscopy, CT, MR, and IUS. Methods A systematic review following PRISMA guidelines, from inception to October 6, 2024, was conducted using MEDLINE, Scopus, CINAHL, and CENTRAL databases to identify literature on diagnostic imaging of patients with colonic CD strictures. Only studies with comparison to endoscopy or imaging to a full-thickness histologic gold standard to differentiate fibrosis from inflammation were included. Two stage screening was completed in duplicate, and risk of bias was assessed using QUADAS-2. Results 46 studies were eligible for inclusion of 4623 abstracts screened. Definitions of colonic strictures on CT, MR, and IUS were highly variable with combinations of bowel wall thickness, luminal narrowing, and pre-stenotic dilation. Endoscopic definitions of colonic strictures were the most consistently reported as lack of passage of a colonoscope through a narrowed lumen. Diagnostic imaging definitions used various combinations of increased bowel wall thickness, luminal narrowing, and pre-stenotic dilation with no clear cutoffs. Few studies directly compared imaging features with histologic or endoscopic gold standards, limiting evaluation of diagnostic accuracy. Meta-analyses were not conducted due to methodological heterogeneity of grading fibrosis across studies. In addition, statistical heterogeneity of sensitivity, specificity, and accuracy of colonic stricture diagnoses was limited by pooling with small bowel strictures in the studies. Conclusion This systematic review highlighted the absence of standardized definitions for diagnosing colonic Crohn’s disease strictures, particularly on diagnostic imaging, and the limited data distinguishing inflammatory from fibrotic components. Bowel wall thickening, luminal narrowing, and pre-stenotic dilation are key features of small bowel strictures, but their relevance to the colon requires further assessment. Establishing standardized definitions for colonic strictures that incorporate both endoscopic and imaging modalities is essential to advancing the field. Conflict of interest: Dr. Lu, Cathy: Advisory board - Abbvie, Johnson and Johnson, Takeda, Ferring, Merck, Celltrion, Lilly, Pfizer, Pendopharm, Agomab. Research Funding - Abbvie, Helmsley Charitable Trust, Alberta Innovates Dhaliwal, Ravdip: No conflict of interest Kellar, Amelia: No conflict of interest Rowan, Catherine: No conflict of interest St-Pierre, Joelle: Consultant for Pfizer, Abbvie, Eli Lilly and Pendopharm, and speaker for Takeda. Ernest-Suárez, Kenneth: Consulting/Advisory Board fees: Abbvie, AstraZeneca, Johnson & Johnson, Pfizer, Ferring, Sandoz, SatisfAI, Takeda O’Brien, Maureen: No conflict of interest Rosentreter, Ryan: No conflict of interest Gulhati, Vishrut: No conflict of interest Baker, Mark: No conflict of interest Bettenworth, Dominik: DB is on the advisory board or consultant for AbbVie, Amgen, Arena, Atheneum, BNG Service GmbH, Bristol Myers Squibb, CED-Service GmbH, Celltrion, Doctorflix, DGVS, Diaplan, Else Kröner-Fresenius Foundation, Falk Foundation, Galapagos, Guidepoint, Impulze, Ferring, Janssen Cilag, Lilly, Medical Tribune, MedTriX, MSD, Mylan, Onkowissen, Pharmacosmos, Pfizer, Roche, Sandoz, Takeda, Tetrameros, Thieme, Tillotts Pharma, UCB Biopiharma, Viatris and Vifor Pharma. Bruining, David: Advisory board fees from Janssen Bari, Dane: Grant from Helmsley Charitable Trust speaker honorarium from Siemens Healthineers support for attending meetings or travel from Siemens Healthineers member of the Olympus advisory board co-chair Society of Abdominal Radiology (SAR) Inflammatory Bowel Disease Disease Focused Panel (IBD DFP) and SAR Photon-Counting Detector CT Emerging Technology Commission and chair of the Society for Advanced Body Imaging Scientific Committee. Dillman, Jonathan: Grants from Philips Healthcare, GE HealthCare, Motilent, Perspectum, Guerbet, and Bracco. El Ouali, Sara: Speaker and/or consulting fees from Takeda, Eli Lilly, Janssen, Abbvie. Fletcher, John: Grant supports from Siemens Healthineers Gordon, Ilyssa: Grants to institution from Morphic Therapeutics, Alimentiv, Pliant Therapeutics, and UCB patent pending with Case Western Reserve University on radiomics signatures Jairath, Vipul: Consulting Fees: Abbvie, Alimentiv, Amgen, Anaptys Bio, Asahi Kasei, Asieris, Astra Zeneca, Attovia, Blackbird Labs, BMS, Boehringer Ingleheim, Biomebank, Caldera, Calluna, Catalytic Health, Celltrion, Ensho, Enthera, Exeliome Biosciences, Ferring, Fresenius Kabi, Gilead, Granite Bio, GSK, Janssen, Lilly, Merck, Mountainfield, MRM Health, Nxera, Organon, OSE Immunotherapeutics, Pendopharm, Pioneering Medicine, Pfizer, Prometheus, Roche/Genentech, Sanofi, SCOPE, Shattuck Labs, Sorriso, Spyre, Synedgen, Takeda, Teva, Tillotts, Union Therapeutics, Ventus, Ventyx, Vividion, Xencor, Zealand Pharma. Feagan, Brian Gordon: Consulting Fees: AbbVie, Abivax, Adaxion, Adiso, AgomAB Therapeutics, Akros, Alira Health, Ally Bridge Group, Apini Therapeutics, Argenx, Attovia Tx, Avoro Capital Advisors, Belmore Law, Biora Therapeutics, Blackbird Laboratories, Boehringer-Ingelheim, BMS, Boxer Capital, Celgene/BMS, Clarivate, Connect Biopharm, EcoR1, Eli Lilly, Ensho Therapeutics, Equillium, Evida, Enveda, Evommune Inc. Faes Farma, First Wave, Forbion, Galapagos, Genentech/Roche, General Atlantic, Genesis Therapeutics, Gerson Lehrman Group, Gilead, Guidepoint, Imhotex, ImiDomics, Immunic Therapeutics, Janssen, Japan Tobacco Inc., LifeMine Therapeutics, Mage Biologics, Merck, Mirador Therapeutics, Mobius Care, Monte Rosa Tx, Morphic Therapeutics, Nimbus Therapeutics, Novartis, Nxera, OncoC3, Palisade Bio, Pendopharm, Pfizer,Q32 Bio, REDX, Roche, Sanofi, Sobi, Sorriso, Spyre Therapeutics, Sun Pharma, Surrozen Inc., Synedgen, Takeda, Tegus Inc., Teva, Tillotts, Trex Bio, TR1X Inc. TVM Lifesciences, Ventyx Biosciences, Versant Ventures, Vida Ventures, Ysios Capital, Zagbio Stock Shareholder: Connect Biopharm, EnGene, Evida, SRT, Imidomics, Enveda Rieder, Florian: Personal Fees: Adiso, Adnovate, Agomab, Allergan, AbbVie, Arena, Astra Zeneca, Boehringer-Ingelheim, Celgene/BMS, Celltrion, CDISC, Celsius, Cowen, Ferring, Galapagos, Galmed, Genentech, Gilead, Gossamer, Granite, Guidepoint, Helmsley, Horizon Therapeutics, Image Analysis Limited, Index Pharma, Landos, Jannsen, Koutif, Mestag, Metacrine, Mopac, Morphic, Organovo, Origo, Palisade, Pfizer, Pliant, Prometheus Biosciences, Receptos, RedX, Roche, Samsung, Sanofi, Surmodics, Surrozen, Takeda, Techlab, Teva, Theravance, Thetis, UCB, Ysios, 89Bio

This consensus by the Society of Abdominal Radiology Inflammatory Bowel Disease Disease Focused Panel provides an updated imaging-based definition of small bowel Crohn disease stricture for CT and MR enterography.

Abstract Background Small bowel fibrostenotic strictures are common in patients with Crohn’s disease (CD). No global consensus recommendations on definitions, diagnosis and clinical management are available. Methods Several systematic reviews followed by a RAND/University of California Los Angeles appropriateness study on the definitions, diagnosis and clinical management of fibrostenosing CD in clinical practice were performed. A panel of 28 global experts and a patient representative were convened. They assessed a total of 152 candidate items. The items were subsequently evaluated for appropriateness. Results No accurate predictive biomarkers are available for naïve or anastomotic fibrostenosing strictures. Accurate diagnosis of fibrostenosing CD requires cross-sectional imaging which should evaluate bowel wall thickness, luminal narrowing and prestenotic dilatation. A potential inflammatory component should be assessed. Abdominal cross-sectional imaging was considered necessary prior to any treatment decision. The panel proposed an approach to medical, endoscopic, and surgical therapies (Figure 1 and Table 1). Technical characteristics for endoscopic balloon dilation and follow up strategies after successful dilation therapy were identified. Appropriateness, types and performance of different surgical approaches in various settings were evaluated. Conclusion This global consensus provides clinical guidance for the diagnostic and therapeutic management of patients with fibrostenotic CD.

Abstract Background Network meta-analysis (NMA) using randomised controlled trial (RCT) data can provide indirect evidence on comparative efficacy of various treatments.1 The NMA reported herein was conducted to evaluate infliximab (IFX) and vedolizumab (VDZ) comparative efficacy during maintenance treatment of moderate-to-severe Crohn’s disease (CD) and ulcerative colitis (UC), covering various dosing regimens and administration routes for each biologic. Methods Studies were identified by literature searches that included publications up to 1 November 2022. Parallel-group RCTs evaluating IFX or VDZ (intravenous [IV] or subcutaneous [SC]) for maintenance treatment of adult patients with moderate-to-severe CD or UC that reported clinical remission rates were included. Eligible studies treated patients for a minimum of 22 weeks, with follow-up of 30–60 weeks for maintenance. Clinical remission rates in tumour necrosis factor inhibitor (TNFi)-naïve patients from each study were analysed in a Bayesian NMA fixed-effect model. Results Overall, 13 RCTs were identified and included in the analysis (Table 1 for CD and Table 2 for UC). The difference in study design between IFX (treat-through) and VDZ (re-randomisation of induction responders only) was noted. A connected network of evidence could be generated using CD and UC studies (Figures 1A and 1B, respectively). In both CD and UC, IFX SC 120 mg had the highest odds ratio (95% confidence interval [CI]) vs. placebo for clinical remission during the maintenance phase (CD: 5.90 [1.90–18.2]; UC: 5.45 [1.94–15.3]), albeit with the CIs overlapping with the CIs of the other tested regimens (Figures 2A and 2B). In both CD and UC, IFX SC 120 mg ranked highest for clinical remission among the biological agents, dosing regimens, and routes of administration tested. Conclusion In both CD and UC, IFX SC showed a favourable efficacy profile for achieving clinical remission during maintenance treatment of TNFi-naïve adult patients, when compared with the other IFX IV or VDZ IV/SC regimens tested. References: 1 Rouse B et al., Intern Emerg Med 2017;12(1):103-111.

Intestinal fibrosis is considered an inevitable complication of Crohn’s disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective antifibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver, and skin. In this review, we summarize data from randomized controlled trials (RCTs) of antifibrotic therapies in these conditions. Multiple compounds have been tested for antifibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators, and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

Objective Effective medical therapy and validated trial outcomes are lacking for small bowel Crohn’s disease (CD) strictures. Histopathology of surgically resected specimens is the gold standard for correlation with imaging techniques. However, no validated histopathological scoring systems are currently available for small bowel stricturing disease. We convened an expert panel to evaluate the appropriateness of histopathology scoring systems and items generated based on panel opinion. Design Modified RAND/University of California Los Angeles methodology was used to determine the appropriateness of 313 candidate items related to assessment of CD small bowel strictures. Results In this exercise, diagnosis of naïve and anastomotic strictures required increased bowel wall thickness, decreased luminal diameter or internal circumference, and fibrosis of the submucosa. Specific definitions for stricture features and technical sampling parameters were also identified. Histopathologically, a stricture was defined as increased thickness of all layers of the bowel wall, fibrosis of the submucosa and bowel wall, and muscularisation of the submucosa. Active mucosal inflammatory disease was defined as neutrophilic inflammation in the lamina propria and any crypt or intact surface epithelium, erosion, ulcer and fistula. Chronic mucosal inflammatory disease was defined as crypt architectural distortion and loss, pyloric gland metaplasia, Paneth cell hyperplasia, basal lymphoplasmacytosis, plasmacytosis and fibrosis, or prominent lymphoid aggregates at the mucosa/submucosa interface. None of the scoring systems used to assess CD strictures were considered appropriate for clinical trials. Conclusion Standardised assessment of gross pathology and histopathology of CD small bowel strictures will improve clinical trial efficiency and aid drug development.

Patients with Crohn’s disease commonly develop ileal and less commonly colonic strictures, containing various degrees of inflammation and fibrosis. While predominantly inflammatory strictures may benefit from a medical anti-inflammatory treatment, predominantly fibrotic strictures currently require endoscopic balloon dilation or surgery. Therefore, differentiation of the main components of a stricturing lesion is key for defining the therapeutic management. The role of endoscopy to diagnose the nature of strictures is limited by the superficial inspection of the intestinal mucosa, the lack of depth of mucosal biopsies and by the risk of sampling error due to a heterogeneous distribution of inflammation and fibrosis within a stricturing lesion. These limitations may be in part overcome by cross-sectional imaging techniques such as ultrasound, CT and MRI, allowing for a full thickness evaluation of the bowel wall and associated abnormalities. This systematic literature review provides a comprehensive summary of currently used radiologic definitions of strictures. It discusses, by assessing only manuscripts with histopathology as a gold standard, the accuracy for diagnosis of the respective modalities as well as their capability to characterise strictures in terms of inflammation and fibrosis. Definitions for strictures on cross-sectional imaging are heterogeneous; however, accuracy for stricture diagnosis is very high. Although conventional cross-sectional imaging techniques have been reported to distinguish inflammation from fibrosis and grade their severity, they are not sufficiently accurate for use in routine clinical practice. Finally, we present recent consensus recommendations and highlight experimental techniques that may overcome the limitations of current technologies.