Contemporary Imaging Assessment of Strictures and Fibrosis in Crohn Disease, With Focus on Quantitative Biomarkers: From the AJR Special Series on Imaging of Fibrosis.

Patients with Crohn disease commonly have bowel strictures develop, which exhibit varying degrees of inflammation and fibrosis. Differentiation of the distinct inflammatory and fibrotic components of strictures is key for the optimization of therapeutic management and for the development of antifibrotic drugs. Cross-sectional imaging techniques, including ultrasound, CT, and MRI, allow evaluation of the full thickness of the bowel wall as well as extramural complications and associated mesenteric abnormalities. Although promising data have been reported for a range of novel imaging biomarkers for detection of fibrosis and quantification of the degree of fibrosis, these biomarkers lack sufficient validation and standardization for clinical use. Additional methods, including PET with emerging radiotracers, artificial intelligence, and radiomics, are also under investigation for stricture characterization. In this review, we highlight the clinical relevance of identifying fibrosis in Crohn disease, review the histopathologic aspects of strictures in Crohn disease, summarize the morphologic imaging findings of strictures, and explore contemporary developments in the use of cross-sectional imaging techniques for detecting and characterizing intestinal strictures, with attention given to emerging quantitative biomarkers.

ADC Values for Detecting Bowel Inflammation and Biologic Therapy Response in Patients With Crohn Disease: A Post Hoc Prospective Trial Analysis.

BACKGROUND. New biologic agents for Crohn disease (CD) create a need for noninvasive disease markers. DWI may assess bowel inflammation without contrast agents. OBJECTIVE. The purpose of this study was to evaluate ADC values for identifying bowel inflammation and therapeutic response in patients with CD treated with biologic therapy. METHODS. This study entailed post hoc analysis of prospective trial data. Analysis included 89 patients (median age, 37 years; 49 women, 40 men) with CD treated by biologic therapy who underwent MR enterography (MRE) at baseline and 46 weeks after therapy, from March 2013 to April 2021; 43 patients underwent ileocolonoscopy at both time points. Analysis was conducted at the level of small-bowel and colorectal segments (586 segments analyzed). MR index of activity (MaRIA) score and presence of endoscopic ulcers were determined at both time points. One observer measured bowel wall ADC. Diagnostic performance was evaluated. Dichotomous ADC assessments used a threshold of 1301 × 10-6 mm2/s based on initial ROC analysis; dichotomous MaRIA score assessments used a threshold of 11 (moderate to severe inflammation). A second observer repeated ADC measurements in 15 patients. RESULTS. At baseline, ADC had AUC of 0.92, sensitivity of 78.6%, specificity of 91.4%, and accuracy of 88.2% for detecting segments with MaRIA score 11 or greater. At baseline, AUC for detecting endoscopic ulcers was 0.96 for MaRIA score versus 0.87 for ADC (p < .001); sensitivity, specificity, and accuracy were 70.8%, 90.2%, and 85.1% for ADC and 86.2%, 96.2%, and 93.6% for MaRIA score. At follow-up, ADC had AUC of 0.87, sensitivity of 75.4%, specificity of 83.6%, and accuracy of 80.0% for detecting improvement in MaRIA score to less than 11. At follow-up, AUC for detecting endoscopic ulcer healing was 0.94 for MaRIA score versus 0.84 for ADC (p = .01); sensitivity, specificity, and accuracy were 70.7%, 95.8%, and 84.4% for ADC and 90.2%, 100.0%, and 95.6% for MaRIA score. Interobserver agreement for ADC, based on intraclass correlation coefficient, was 0.70 at baseline and 0.65 at follow-up. CONCLUSION. The findings do not support use of ADC rather than MaRIA scores for detecting biologic therapy response. CLINICAL IMPACT. ADC may have an adjunct role in assessing bowel inflammation in CD, but showed limited performance for detecting biologic therapy response.

De-escalating therapy in inflammatory bowel disease: Results from an observational study in clinical practice.

BACKGROUND AND OBJECTIVES: Combination therapy with an immunomodulator (IMM) and an anti-TNF is commonly recommended in Crohn's disease (CD) and ulcerative colitis (UC) patients. However, little is known about relapse rates after therapeutic de-escalation. This study aimed to evaluate the risk of relapse in a cohort of UC and CD patients with long-standing clinical remission after discontinuation of IMM or anti-TNF and to identify predictive factors for relapse. METHODS: This retrospective study included patients with UC or CD on combination therapy and clinical remission for at least 6 months. IMM or anti-TNF was stopped upon physician decision. Primary objective was to evaluate the relapse rates after discontinuation of IMM or anti-TNF and to analyze predictors of relapse. RESULTS: The study included 88 patients, 48 patients (54.5%) discontinued IMM and 40 (45.5%) anti-TNF. During follow-up, relapse rates were 16.7% and 52.5% in the IMM discontinuation group and anti-TNF discontinuation group, respectively (p<0.001). Multivariate analysis showed that anti-TNF discontinuation (HR=3.01; 95% CI=1.22-7.43) and ileal CD location (HR=2.36; 95% CI=1.02-5.47) were predictive factors for relapse while inflammatory CD phenotype was a protective factor (HR=0.32; 95% CI=0.11-0.90). Reintroduction of anti-TNF upon relapse was effective and safe. CONCLUSION: Anti-TNF discontinuation led to significantly higher relapse rates compared to IMM discontinuation in UC and CD patients on combination therapy. Anti-TNF discontinuation and ileal CD location were identified as predictive factors for relapse while inflammatory CD phenotype was a protective factor. Retreatment after anti-TNF discontinuation was effective and safe.

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.

Development and Validation of a Simplified Magnetic Resonance Index of Activity for Crohn's Disease.

BACKGROUND & AIMS: The magnetic resonance index of activity (MARIA) for Crohn's disease (CD) is used to assess the activity of luminal CD. However, it has a number of practical limitations. We aimed to develop and validate a simplified MARIA to more easily and quickly assess CD activity and response to therapy. PATIENTS AND METHODS: We performed a retrospective analysis of magnetic resonance imaging data from 98 participants in 2 studies. We used logistic regression analysis to identify magnetic resonance imaging parameters independently associated with CD endoscopic index of severity (CDEIS) scores (the reference standard). We validated the responsiveness and reliability of the simplified MARIA in an independent cohort of 37 patients who underwent magnetic resonance imaging and endoscopy before and after a therapeutic intervention. RESULTS: Logistic regression analysis showed that dichotomous qualitative assessment of wall thickening (>3 mm), presence of mural edema, perienteric fat stranding, and ulcers were independently associated with CDEIS scores; we used these factors to create a simplified MARIA. Simplified MARIA scores greater than 1 identified segments with active CD with 90% sensitivity and 81% specificity (area under the curve 0.91; 95% confidence interval 0.88-0.94). Simplified MARIA scores of 2 or more detected severe lesions (ulcers) with 85% sensitivity and 92% specificity (area under the curve 0.94; 95% confidence interval 0.91-0.96). For each patient, there was a high level of correlation between simplified MARIA scores and CDEIS scores (r = 0.83) and simplified MARIA scores and original MARIA scores (and r = 0.93) (P < .001). The simplified MARIA score accurately detected changes in lesion severity in response to therapy and was as reliable as endoscopy for the assessment of mucosal healing. CONCLUSION: We developed and validated a simplified MARIA for easier and faster assessment of CD activity and severity. This index identifies patients with a response to therapy with a high level of accuracy. These findings require confirmation in independent, multireader studies.

Changes in the requirement for early surgery in inflammatory bowel disease in the era of biological agents.

BACKGROUND AND AIM: Biological therapies may be changing the natural history of inflammatory bowel diseases (IBDs), reducing the need for surgical intervention. We aimed to assess whether the availability of anti-TNF agents impacts the need for early surgery in Crohn's disease (CD) and ulcerative colitis (UC). METHODS: Retrospective, cohort study of patients diagnosed within a 6-year period before and after the licensing of anti-TNFs (1990-1995 and 2007-2012 for CD; 1995-2000 and 2007-2012 for UC) were identified in the ENEIDA Registry. Surgery-free survival curves were compared between cohorts. RESULTS: A total of 7370 CD patients (2022 in Cohort 1 and 5348 in Cohort 2) and 8069 UC patients (2938 in Cohort 1 and 5131 in Cohort 2) were included. Immunosuppressants were used significantly earlier and more frequently in both CD and UC post-biological cohorts. The cumulative probability of surgery was lower in CD following anti-TNF approval (16% and 11%, 22% and 16%, and 29% and 19%, at 1, 3, and 5 years, respectively P < 0.0001), although not in UC (3% and 2%, 4% and 4%, and 6% and 5% at 1, 3, and 5 years, respectively; P = 0.2). Ileal involvement, older age at diagnosis and active smoking in CD, and extensive disease in UC, were independent risk factors for surgery, whereas high-volume IBD centers (in both CD and UC) and immunosuppressant use (in CD) were protective factors. CONCLUSIONS: Anti-TNF availability was associated with a reduction in early surgery for CD (driven mainly by earlier and more widespread immunosuppressant use) but not in UC.

Is endoscopic treatment of small bowel strictures effective and safe in patients with Crohn's disease?

INTRODUCTION: there is very little scientific evidence about the efficacy of endoscopic balloon dilation (EBD) performed with balloon-assisted enteroscopy (BAE) for the treatment of small bowel strictures (SBS) in Crohn's disease (CD). OBJECTIVE: to evaluate the efficacy and safety of EBD using BAE in patients with CD and SBS. METHODS: a retrospective observational study was performed in a tertiary care medical center in patients with CD and SBS, evaluated by CT enterography or MRI enterography. RESULTS: from 2009 to 2019, 205 endoscopic dilations were performed in 80 patients with CD. 17 (21.25 %) had only SBS and 70.6 % were male with a median age of 42.2 (±14.4) years. The mean follow-up was 37.8 ±28.7 months. A total of 39 dilations were performed, 94.1 % were native and less than 5cm long, all strictures were ulcerated. The overall technical success was 82.4 % and clinical success was 88.2 %. During follow-up, 23.5 % of patients required surgery and 29.4 % were re-dilated. The long-term efficacy was 76.5 % and no severe adverse events (AE) were observed. No factors were identified to predict the need for surgery after dilation. CONCLUSIONS: SBS can be safely and effectively treated with EBD using BAE, thus reducing the need for surgery in the long term.

Alterations in the epithelial stem cell compartment could contribute to permanent changes in the mucosa of patients with ulcerative colitis.

OBJECTIVE: UC is a chronic inflammatory disease of the colonic mucosa. Growing evidence supports a role for epithelial cell defects in driving pathology. Moreover, long-lasting changes in the epithelial barrier have been reported in quiescent UC. Our aim was to investigate whether epithelial cell defects could originate from changes in the epithelial compartment imprinted by the disease. DESIGN: Epithelial organoid cultures (EpOCs) were expanded ex vivo from the intestinal crypts of non-IBD controls and patients with UC. EpOCs were induced to differentiate (d-EpOCs), and the total RNA was extracted for microarray and quantitative real-time PCR (qPCR) analyses. Whole intestinal samples were used to determine mRNA expression by qPCR, or protein localisation by immunostaining. RESULTS: EpOCs from patients with UC maintained self-renewal potential and the capability to give rise to differentiated epithelial cell lineages comparable with control EpOCs. Nonetheless, a group of genes was differentially regulated in the EpOCs and d-EpOCs of patients with UC, including genes associated with antimicrobial defence (ie, LYZ, PLA2G2A), with secretory (ie, ZG16, CLCA1) and absorptive (ie, AQP8, MUC12) functions, and with a gastric phenotype (ie, ANXA10, CLDN18 and LYZ). A high rate of concordance was found in the expression profiles of the organoid cultures and whole colonic tissues from patients with UC. CONCLUSIONS: Permanent changes in the colonic epithelium of patients with UC could be promoted by alterations imprinted in the stem cell compartment. These changes may contribute to perpetuation of the disease.

Agreement Between Rectosigmoidoscopy and Colonoscopy Analyses of Disease Activity and Healing in Patients With Ulcerative Colitis.

BACKGROUND & AIMS: Endoscopy limited to the rectosigmoid colon is the standard technique used to measure endoscopic healing in ulcerative colitis (UC) clinical trials. We evaluated whether rectosigmoidoscopy adequately measures UC activity in the more proximal colon. METHODS: We analyzed data from a phase 2, placebo-controlled study that evaluated the efficacy and safety of etrolizumab in patients with moderate to severely active UC who had not responded to standard therapy. Central readers determined Mayo Clinic endoscopic subscores (MCSe) and ulcerative colitis endoscopic index of severity (UCEIS) scores from the rectosigmoid and proximal colon in videos of 331 examinations performed at baseline, week 6, and week 10. Rates of endoscopic healing (MCSe ≤ 1, MCSe = 0) and scores from rectosigmoidoscopy and colonoscopy analyses were compared among 239 examinations with endoscopic assessment proximal to the rectosigmoid colon. RESULTS: There was a high degree of correlation between findings from rectosigmoidoscopy vs colonoscopy in assessment of disease activity based on MCSe of 2 or higher (r = 0.84) or MCSe of 1 or higher (r = 0.96), or the UCEIS score (r = 0.92). In 230 of 239 videos, findings from rectosigmoidoscopy agreed with those from colonoscopy in the detection of active disease (MCSe ≥ 2; n = 205) or healing (MCSe ≤ 1; n = 25). In 9 videos (2 taken at baseline, 7 taken after treatment), colonoscopy found proximal disease activity not detected by rectosigmoidoscopy. Post-treatment discordance was more frequent in the placebo group, affecting assessment of efficacy at week 10. When endoscopic healing was defined as MCSe of 0, there were discordant findings from only 1 video. CONCLUSIONS: There is a high degree of correlation in assessments of UC activity made by rectosigmoidoscopy vs colonoscopy. For detection of endoscopic healing (MCSe ≤ 1), colonoscopy found persistent proximal lesions in the placebo group, which affected efficacy analyses. When endoscopic healing was defined as MCSe of 0, the concordance between rectosigmoidoscopy and colonoscopy was nearly perfect.

Commensal-Specific CD4(+) Cells From Patients With Crohn's Disease Have a T-Helper 17 Inflammatory Profile.

BACKGROUND & AIMS: Crohn's disease (CD) has been associated with an altered immune response to commensal microbiota, mostly based on increased seroreactivity to microbial proteins. Although T cells are believed to contribute to the development of CD, little is known about the antigens involved. We investigated the antigen-specificity of T cells isolated from patients with CD. METHODS: We isolated peripheral blood mononuclear cells from 65 patients with CD and 45 healthy individuals (controls). We investigated T-cell reactivity to commensal microbial antigens using proliferation assays (based on thymidine incorporation and carboxyfluorescein succinimidyl ester dilution). Gene expression patterns were determined using microarray and real-time polymerase chain reaction analyses. Cytokines, chemokines, and antibodies were measured by enzyme-linked immunosorbent assay, flow cytometry, or multiplex cytokine assays. Intestinal crypts were obtained from surgical resection specimens of 7 individuals without inflammatory bowel disease. We examined the effects of commensal-specific CD4(+) T cells on primary intestinal epithelial cells from these samples. RESULTS: The bacterial proteins FlaX, A4-fla2, and YidX increased proliferation of CD4(+) T cells isolated from peripheral blood of patients with CD compared with controls. In blood samples from controls, CD4(+) T cells specific for FlaX, A4-fla2, or YidX had a T-helper (Th)1 phenotype; a larger proportion of CD4(+) T cells specific for these proteins in patients with CD had a Th17 phenotype or produced Th1 and Th17 cytokines. When supernatants collected from commensal-specific CD4(+) T cells from patients with CD were applied to healthy intestinal epithelial cells, the epithelial cells increased the expression of the chemokine (C-X-C motif) ligand 1 (CXCL1), CXCL8 and the CC chemokine ligand 20 (CCL20). CONCLUSIONS: A larger proportion of commensal-specific CD4(+) T cells from patients with CD have a Th17 phenotype or produce Th1 and Th17 cytokines, compared with T cells from controls; this might contribute to intestinal inflammation in patients with CD. These cells might be targeted for treatment of CD. The transcriptional data of commensal-specific CD4(+) T cells from healthy individuals and CD patients have been deposited in the Gene Expression Omnibus at the National Center for Biotechnology Information (accession no: GSE70469).

Improving safety of autologous haematopoietic stem cell transplantation in patients with Crohn's disease.

OBJECTIVE: To evaluate the feasibility and toxicity of autologous haematopoietic stem cell transplantation (HSCT) for the treatment of refractory Crohn's disease (CD). DESIGN: In this prospective study, patients with refractory CD suffering an aggressive disease course despite medical treatment, impaired quality of life and in whom surgery was not an acceptable option underwent HSCT. Toxicity and complications during the procedure and within the first year following transplantation were evaluated, along with the impact of the introduction of supportive measures on safety outcomes. RESULTS: 26 patients were enrolled. During mobilisation, 16 patients (62%) presented febrile neutropaenia, including one bacteraemia and two septic shocks. Neutropaenia median time after mobilisation was 5 days. 5 patients withdrew from the study after mobilisation and 21 patients entered the conditioning phase. Haematopoietic recovery median time for neutrophils (>0.5×10(9)/L) was 11 days and for platelets (>20×10(9)/L) 4 days. Twenty patients (95%) suffered febrile neutropaenia and three patients (27%) presented worsening of the perianal CD activity during conditioning. Among non-infectious complications, 6 patients (28.5%) presented antithymocyte globulin reaction, 12 patients (57%) developed mucositis and 2 patients (9.5%) had haemorrhagic complications. Changes in supportive measures over the study, particularly antibiotic prophylaxis regimes during mobilisation and conditioning, markedly diminished the incidence of severe complications. During the first 12-month follow-up, viral infections were the most commonly observed complications, and one patient died due to systemic cytomegalovirus infection. CONCLUSIONS: Autologous HSCT for patients with refractory CD is feasible, but extraordinary supportive measures need to be implemented. We suggest that this procedure should only be performed in highly experienced centres.

Development of the Lémann index to assess digestive tract damage in patients with Crohn's disease.

BACKGROUND & AIMS: There is a need for a scoring system that provides a comprehensive assessment of structural bowel damage, including stricturing lesions, penetrating lesions, and surgical resection, for measuring disease progression. We developed the Lémann Index and assessed its ability to measure cumulative structural bowel damage in patients with Crohn's disease (CD). METHODS: We performed a prospective, multicenter, international, cross-sectional study of patients with CD evaluated at 24 centers in 15 countries. Inclusions were stratified based on CD location and duration. All patients underwent clinical examination and abdominal magnetic resonance imaging analyses. Upper endoscopy, colonoscopy, and pelvic magnetic resonance imaging analyses were performed according to suspected disease locations. The digestive tract was divided into 4 organs and subsequently into segments. For each segment, investigators collected information on previous operations, predefined strictures, and/or penetrating lesions of maximal severity (grades 1-3), and then provided damage evaluations ranging from 0.0 (no lesion) to 10.0 (complete resection). Overall level of organ damage was calculated from the average of segmental damage. Investigators provided a global damage evaluation (from 0.0 to 10.0) using calculated organ damage evaluations. Predicted organ indexes and Lémann Index were constructed using a multiple linear mixed model, showing the best fit with investigator organ and global damage evaluations, respectively. An internal cross-validation was performed using bootstrap methods. RESULTS: Data from 138 patients (24, 115, 92, and 59 with upper tract, small bowel, colon/rectum, and anus CD location, respectively) were analyzed. According to validation, the unbiased correlation coefficients between predicted indexes and investigator damage evaluations were 0.85, 0.98, 0.90, 0.82 for upper tract, small bowel, colon/rectum, anus, respectively, and 0.84 overall. CONCLUSIONS: In a cross-sectional study, we assessed the ability of the Lémann Index to measure cumulative structural bowel damage in patients with CD. Provided further successful validation and good sensitivity to change, the index should be used to evaluate progression of CD and efficacy of treatment.

Long-Term Follow-Up of Patients Treated with Infliximab for Ulcerative Colitis: Predictive Factors of Response-An Observational Study.

AIM: To evaluate the early and long-term efficacy of infliximab in ulcerative colitis and to determine predictors of response and colectomy. METHODS: This is an ambidirectional cohort study in a tertiary referral center including patients who started infliximab within 2005 and 2008 and monitored until 2014. Efficacy was evaluated by partial Mayo scores at weeks 2, 4, 8, 30, and 54. Long-term treatment maintenance with infliximab and colectomy requirements were recorded. RESULTS: Fifty-three patients were included with a median follow-up of 69.5 months. Clinical remission at the time point assessments was 40.8, 47.2, 54.7, 54.7, and 49.1 %. At the time of maximal follow-up, the proportion of patients under infliximab maintenance was 24.5 %. A higher level of albumin (OR 1.4, CI 95 % 1.06-1.8; p = 0.017) was predictive of a higher remission rate at week 8. Concomitant immunomodulators beyond 6 months were predictive of infliximab's long-term maintenance (OR 15.8, CI 95 % 1.8-135.4; p = 0.012). Colectomy was required in 41.5 %. Factors associated with a higher rate of colectomy at week 54 were previous treatment with cyclosporine (OR 3.4, CI 95 % 1.2-9.7; p = 0.012), absence of response at week 8 (OR 10.3, CI 95 % 3.3-31.7; p < 0.001), and not receiving concomitant immunomodulators (OR 4.1, CI 95 % 1.8-9; p = 0.002). Colectomy rates within the first 54 weeks were closely dependent on the number of variables present: none (0 %), 1 (26.3 %), 2 (71.4 %), or 3 (100 %) of them (log rank <0.0001). CONCLUSIONS: Low albumin, previous treatment with cyclosporine, absence of a concomitant immunomodulator, and lack of response at week 8 negatively affected the efficacy of infliximab in ulcerative colitis.

Identification of inflammatory mediators in patients with Crohn's disease unresponsive to anti-TNFα therapy.

BACKGROUND: Anti-tumour necrosis factor α (TNFα) therapy effectively induces and maintains remission in Crohn's disease (CD). Up to 40% of patients, however, fail to respond to anti-TNFα. OBJECTIVE: To identify the mechanisms underlying the persistence of mucosal lesions in patients who fail to respond to anti-TNFα therapy. DESIGN: An observational study based on whole-genome transcriptional analysis was carried out using intestinal biopsy specimens from patients with CD receiving (n=12) or not (n=10) anti-TNFα therapy. The transcriptional signature of responders was compared with that of non-responders after anti-TNFα therapy. Controls with non-inflammatory bowel disease (non-IBD) (n=17) were used for comparisons. Genes of interest were validated by real-time RT-PCR in an independent cohort of patients with CD receiving (n=17) or not (n=16) anti-TNFα and non-IBD controls (n=7). RESULTS: We confirmed that response to anti-TNFα is accompanied by significant regulation of a large number of genes, including IL1B, S100A8, CXCL1, which correlated with endoscopic activity. Remarkably, patients who failed to respond to anti-TNFα showed a mixed signature, maintaining increased expression of IL1B, IL17A and S100A8, while showing significant modulation of other genes commonly upregulated in active CD, including IL6 and IL23p19. CONCLUSIONS: Our results show that anti-TNFα therapy significantly downregulates a subset of inflammatory genes even in patients who fail to achieve endoscopic remission, suggesting that these genes may not be dominant in driving inflammation in non-responders. On the other hand, we identified IL1B and IL17A as genes that remained altered in non-responders, pointing to potentially more relevant targets for modulating mucosal damage in refractory patients.

Accuracy of magnetic resonance enterography in assessing response to therapy and mucosal healing in patients with Crohn's disease.

BACKGROUND & AIMS: We assessed the accuracy of magnetic resonance enterography (MRE) in monitoring response to therapy in patients with Crohn's disease (CD) using ileocolonoscopy as a reference standard. METHODS: We performed a prospective multicenter study of 48 patients with active CD and ulcers in at least one ileocolonic segment. All patients underwent ileocolonoscopy and MRE at baseline and 12 weeks after completing treatment with corticosteroids (CS) or anti-tumor necrosis factor agents. Disease activity was quantified using Crohn's Disease Endoscopic Index of Severity (CDEIS) and Magnetic Resonance Index of Activity (MaRIA). The primary analysis was to determine the accuracy of MRE in identification of healing, defined as the disappearance of ulcers in endoscopy examination. Additional analyses established the accuracy of MRE in determining endoscopic remission (a CDEIS score <3.5) and change in severity based on consideration of all segments. RESULTS: MRE determined ulcer healing with 90% accuracy and endoscopic remission with 83% accuracy. The mean CDEIS and MaRIA scores significantly changed at week 12 in segments with ulcer healing, based on endoscopic examination (CDEIS: 21.28 ± 9.10 at baseline vs 2.73 ± 4.12 at 12 weeks; P < .001 and MaRIA: 18.86 ± 9.50 at baseline vs 8.73 ± 5.88 at 12 weeks; P < .001). The MaRIA score accurately detected changes in lesion severity (Guyatt score: 1.2 and standardized effect size: 1.07). MRE was as reliable as endoscopy in assessing healing; no significant changes in CDEIS or MaRIA scores were observed in segments with persistent ulcers, based on endoscopic examination (CDEIS: 26.43 ± 9.06 at baseline vs 20.77 ± 9.13 at 12 weeks; P = .18 and MaRIA: 22.13 ± 8.42 at baseline vs 20.77 ± 9.17 at 12 weeks; P = .42). The magnitude of change in CDEIS scores correlated with those in MaRIA scores (r = 0.51; P < .001). CONCLUSIONS: MRE evaluates ulcer healing with a high level of accuracy when ileocolonoscopy is used as the reference standard. The MaRIA is a valid, responsive, and reliable index assessing response to therapy in patients with CD.

Characterization of inflammation and fibrosis in Crohn's disease lesions by magnetic resonance imaging.

OBJECTIVES: Measurement of the component of fibrosis in Crohn's disease (CD) may have important therapeutic implications. The aim of this study was to characterize the Magnetic Resonance Imaging (MRI) findings that are differentially associated with the presence of fibrosis and those associated with inflammatory activity, using the pathological analysis of surgically resected intestinal lesions as reference standard. METHODS: MRI studies with identical imaging protocol of 41 CD patients who underwent elective bowel resection within 4 months before surgery were reviewed. MRI evaluated wall thickening, edema, ulcers, signal intensity at submucosa at 70 s and 7 min after gadolinium injection, stenosis, and pattern of enhancement in each phase of the dynamic study and changes on this pattern over time. Pathological inflammatory and fibrosis scores were classified into three grades of severity. RESULTS: In all, 44 segments from 41 patients were analyzed. The pathological intensity of inflammation was associated with the following MRI parameters: hypersignal on T2 (P=0.02), mucosal enhancement (P=0.03), ulcerations (P=0.01), and blurred margins (P=0.05). The degree of fibrosis correlated with the percentage of enhancement gain (P<0.01), the pattern of enhancement at 7 min (P<0.01), and the presence of stenosis (P=0.05). Using percentage of enhancement gain, MRI is able to discriminate between mild-moderate and severe fibrosis deposition with a sensitivity of 0.94 and a specificity of 0.89. CONCLUSIONS: MRI is accurate for detecting the presence of severe fibrosis in CD lesions on the basis of the enhancement pattern.

Magnetic resonance enterography in Crohn's disease: optimal use in clinical practice and clinical trials.

The purpose of this review is to provide a practical appraisal of the usefulness of magnetic resonance enterography in the management of Crohn's disease and the potential utilities that this imaging modality may have in clinical research. Also, we review some basic technical considerations that clinicians should know to understand the value and limitations of the technique. Lastly, we outline the future trends and potential contributions of new technological advances in the field of magnetic resonance imaging that can improve the classic magnetic resonance enterography technique.

Transcriptional analysis of the intestinal mucosa of patients with ulcerative colitis in remission reveals lasting epithelial cell alterations.

OBJECTIVE: Ulcerative colitis (UC) is a chronic condition characterised by the relapsing inflammation despite previous endoscopic and histological healing. Our objective was to identify the molecular signature associated with UC remission. DESIGN: We performed whole-genome transcriptional analysis of colonic biopsies from patients with histologically active and inactive UC, and non-inflammatory bowel disease (non-IBD) controls. Real-time reverse transcriptase-PCR and immunostaining were used for validating selected genes in independent cohorts of patients. RESULTS: Microarray analysis (n=43) demonstrates that UC patients in remission present an intestinal transcriptional signature that significantly differs from that of non-IBD controls and active patients. Fifty-four selected genes were validated in an independent cohort of patients (n=30). Twenty-nine of these genes were significantly regulated in UC-in-remission subjects compared with non-IBD controls, including a large number of epithelial cell-expressed genes such as REG4, S100P, SERPINB5, SLC16A1, DEFB1, AQP3 and AQP8, which modulate epithelial cell growth, sensitivity to apoptosis and immune function. Expression of inflammation-related genes such as REG1A and IL8 returned to control levels during remission. REG4, S100P, SERPINB5 and REG1A protein expression was confirmed by immunohistochemistry (n=23). CONCLUSIONS: Analysis of the gene signature associated with remission allowed us to unravel pathways permanently deregulated in UC despite histological recovery. Given the strong link between the regulation of some of these genes and the growth and dissemination of gastrointestinal cancers, we believe their aberrant expression in UC may provide a mechanism for epithelial hyper-proliferation and, in the context of malignant transformation, for tumour growth.

Diagnostic accuracy of magnetic resonance colonography for the evaluation of disease activity and severity in ulcerative colitis: a prospective study.

OBJECTIVE: The aim of this study was to determine the diagnostic accuracy of magnetic resonance colonography (MRC) for the evaluation of disease activity and severity in patients with ulcerative colitis (UC) using endoscopy as the reference standard. METHODS: Fifty patients with UC underwent colonoscopy and MRC for the evaluation of disease activity. All patients were prospectively and consecutively included. Endoscopic activity was evaluated globally and on a segment basis using the modified Baron score (MBS), and also classified as absent, mild to moderate (inflammation without ulcers) or severe (presence of ulceration). MRC parameters evaluated in each segment were: wall thickness, pre- and post-contrast wall signal intensity, relative contrast enhancement (RCE), mural oedema, ulcers, enlarged lymph nodes and the comb sign. RESULTS: Independent predictors for endoscopic activity on a segment basis were RCE (p=0.006), presence of oedema (p=0.003), enlarged lymph nodes (p<0.001) and the comb sign (p<0.001). A segmental simplified MRC index (MRC-S) ≥ 1 detected endoscopic inflammation with high diagnostic accuracy (sensitivity 87%, specificity 88%, area under the curve (AUC) 0.95; p<0.001). MRC-S index ≥ 2 detected severe lesions with high sensitivity (83%) and specificity (82%) with an AUC of 0.91 (p<0.001). The MRC-S index strongly correlated with the MBS (r=0.81, p<0.001) and with the subjective assessment of the radiologists for the evaluation of disease severity (r=0.77, p<0.001). CONCLUSIONS: MRC has a high accuracy for the diagnosis of disease activity and severity in UC.

Magnetic resonance enterography findings 46 weeks after initiation of biological therapy predict long-term adverse outcomes in Crohn's disease.

BACKGROUND AND AIMS: Magnetic resonance enterography (MRE) depicts transmural changes in response to biological treatment for Crohn's disease (CD); however, the long-term prognostic significance of these findings is unknown. The primary objective of this study was to identify findings on MRE 46 weeks after initiating biological treatment that predict adverse long-term outcomes. METHODS: Patients with CD underwent MRE 46 weeks after initiating biological treatment and were prospectively followed for 2 years. A logistic regression analysis was performed to assess the prognostic value of different radiologic findings for various predefined adverse outcomes. RESULTS: Of the 89 patients included, 46 (51.7%) had ≥1 adverse outcome during follow-up: 40 (44.9%) had clinical recurrence; 18 (20.2%) required surgery, 8 (9%) endoscopic balloon dilation, 12 (13.5%) hospitalization and 7 (7.8%) required corticosteroids. In the multivariate analysis, persistence of severe lesions (MaRIA ≥11) in any intestinal segment was associated with an increased risk of surgery [OR 11.6 (1.5-92.4)], of surgery and/or endoscopic balloon dilation [OR 6.3 (1.3-30.2)], and of clinical relapse [OR 4.6 (1.6-13.9)]. Penetrating lesions were associated with surgery [OR 3.4 (1.2-9.9)]. Creeping fat with hospitalization [OR 5.1 (1.1-25.0)] and corticosteroids requirement [OR 16.0 (1.2-210.0)]. The presence of complications (stricturing and/or penetrating lesions) was associated with having ≥1 adverse outcome [OR 3.35 (1.3-8.5)]. CONCLUSION: MRE findings at week-46 after initiating biological therapy can predict long-term adverse outcomes in CD. Therapeutic intervention may be required in patients with persistence of severe inflammatory lesions, CD-associated complications, or creeping fat.