Reliability of Intestinal Ultrasound for Evaluating Crohn's Disease Activity Using Point-of-care and Central Reading.

BACKGROUND & AIMS: Intestinal ultrasound (IUS) is increasingly used to assess Crohn's disease (CD) activity in clinical practice. However, application in clinical trials has been limited by heterogeneous scoring methods and concerns about reliability. We aimed to determine the inter- and intra-rater reliability of locally and centrally read IUS parameters for evaluating CD using prospectively performed scans. METHODS: Twenty-four participants with CD and 6 gastroenterologists participated in a 2-day workshop where each participant underwent 6 IUS scans in total. Eight IUS parameters (bowel wall thickness [BWT], bowel wall stratification [BWS], color Doppler signal [CDS], inflammatory mesenteric fat [i-fat], submucosal prominence, submucosal layer thickness, haustra coli/peristalsis, and affected segment length) and an overall measure of sonographic disease activity were blindly assessed by the 6 local readers and 4 central gastroenterologist-sonographers. Reliability was quantified using intraclass correlation coefficients (ICCs). Institutional review board approval was granted for this study (12938). RESULTS: Five IUS parameters demonstrated at least moderate (ICC ≥0.41) inter- and intra-rater reliability when local and central reading was performed (BWT, CDS, i-fat, submucosal prominence, and affected segment length). Reliability was generally better with central, in distinction to local, reading. ICCs for BWS and i-fat were highest when evaluated as binary outcomes. Sensitivity analyses demonstrated that IUS parameters are most reliable when evaluated in the worst affected segment. Fair reliability was observed when local readers identified the worst affected segment. CONCLUSIONS: Local and central reading of IUS demonstrated at least moderate inter- and intra-rater reliability for several parameters. This study supports refining existing activity indices and incorporating IUS central reading into clinical trials.

Point-of-Care Testing and Home Testing: Pragmatic Considerations for Widespread Incorporation of Stool Tests, Serum Tests, and Intestinal Ultrasound.

Breaking through the biologic therapy efficacy plateau for inflammatory bowel disease requires the strategic development of personalized biomarkers in the tight control model. After risk stratification early in the disease course, targeted serial monitoring consistently to assess clinical outcomes in response to therapy allows for quick therapeutic adjustments before bowel damage can occur. Point-of-care intestinal ultrasound performed by the treating gastroenterologist is an accurate cross- sectional biomarker that monitors intestinal inflammation in real-time, enhances patient care, and increases shared understanding to help achieve common treatment goals. Combining intestinal ultrasound during a clinic visit with existing serum and stool biomarkers in a home testing setup with electronic health monitoring allows for an optimized, patient-centered personalized treatment algorithm that may improve treatment outcomes. Here, we review the current state, pragmatic considerations, and future implications of point-of-care testing and home testing for noninvasive inflammatory bowel disease monitoring in the tight control model.

Early Ultrasound Response and Progressive Transmural Remission After Treatment With Ustekinumab in Crohn's Disease.

BACKGROUND & AIMS: In this STARDUST substudy, the effect of ustekinumab on transmural bowel inflammation was assessed in adults with moderate-to-severe Crohn's disease (CD) by using intestinal ultrasound (IUS), a noninvasive imaging procedure. METHODS: STARDUST was an international, multicenter, phase 3b, interventional, randomized controlled trial specifically designed to compare treat-to-target and standard-of-care treatment strategies in ustekinumab-treated CD patients. In this substudy, the most affected bowel segment at baseline by IUS was used for all analyses. Key IUS endpoints (centrally read, parameter-blinded) were IUS response, transmural remission, bowel wall thickness (BWT), blood flow, bowel wall stratification, and inflammatory fat. RESULTS: Seventy-seven patients were evaluated. IUS response could be determined 4 weeks after treatment initiation, with progressive improvement through week 48. IUS response and transmural remission rates at week 48 were 46.3% and 24.1%, respectively. IUS response, transmural remission, BWT, and blood flow normalization rates were more pronounced in the colon and biologic-naive patients. Fair/moderate reliability (κ = 0.21-0.51) was observed between week 4 IUS response and week 48 overall endoscopic response and fecal calprotectin/complete biomarker outcomes. Endoscopy and IUS baseline agreement was >90% in determining the terminal ileum as the most affected bowel segment. IUS response absence at week 4 was associated with no endoscopic response (based on the simplified endoscopic score for Crohn's disease terminal ileum subscore) at week 48 (negative predictive value = 73%). CONCLUSIONS: In this first international, multicenter, interventional study, IUS showed that ustekinumab-treated CD patients achieved progressive IUS response (46.3%) and transmural remission (24.1%) through week 48, with a more robust response in the colon and biologic-naive patients. CLINICALTRIALS: gov number: NCT03107793.

Comment on "Ultrasonographic scores for ileal Crohn's disease assessment: better, worse or the same as contrast­enhanced ultrasound?"

We read with interest the study by Freitas et al. comparing contrast-enhanced ultrasound (CEUS) and parameters from a time-intensity curve (TIC) with the SUS-CD score and IBUS-SAS score in patients with Crohn's disease (CD) undergoing gastrointestinal ultrasound (GIUS) and ileocolonoscopy. The aim was to compare the accuracy of CEUS and aforementioned scores in predicting terminal ileal inflammatory activity in patients with CD. In this retrospective study of 50 patients, inflammatory activity was defined as a segmental score of SES-CD ≥ 7 in the terminal ileum. The study found 30 patients with active endoscopic disease demonstrating no significant difference between the "inactive" and "active" SUS CD and IBUS-SAS scores. However, the CEUS peak enhancement derived from the TIC was shown to be significantly different. The authors conclude CEUS was superior for detecting inflammation in the terminal ileum, as opposed to ultrasound scores relying on bowel wall thickness and color Doppler.

Quantitative Contrast-Enhanced Ultrasound Parameters in Crohn Disease: Their Role in Disease Activity Determination With Ultrasound.

OBJECTIVE: The primary objective of our study was to examine the association between contrast-enhanced ultrasound (CEUS) parameters and established gray-scale ultrasound with color Doppler imaging (CDI) for the determination of disease activity in patients with Crohn disease. Our secondary objective was to develop quantitative time-signal intensity curve thresholds for disease activity. MATERIALS AND METHODS: One hundred twenty-seven patients with Crohn disease underwent ultrasound with CDI and CEUS. Reviewers graded wall thickness, inflammatory fat, and mural blood flow as showing remission or inflammation (mild, moderate, or severe). If both gray-scale ultrasound and CDI predicted equal levels of disease activity, the studies were considered concordant. If ultrasound images suggested active disease not supported by CDI findings, the ultrasound results for disease activity were indeterminate. Time-signal intensity curves from CEUS were acquired with calculation of peak enhancement (PE), and AUCs. Interobserver variation and associations between PE and ultrasound parameters were examined. Multiclass ROC analysis was used to develop CEUS thresholds for activity. RESULTS: Ninety-six (76%) studies were concordant, 19 of which showed severe disease, and 31 (24%) studies were indeterminate. Kappa analyses revealed good interobserver agreement on grades for CDI (κ = 0.76) and ultrasound (κ = 0.80) assessments. PE values on CEUS and wall thickness showed good association with the Spearman rank correlation coefficient for the entire population (ρ = 0.62, p < 0.01) and for the concordant group (ρ = 0.70, p < 0.01). Multiclass ROC analyses of the concordant group using wall thickness alone as the reference standard showed cutoff points of 18.2 dB for differentiating mild versus moderate activity (sensitivity, 89.0% and specificity, 87.0%) and 23.0 dB for differentiating moderate versus severe (sensitivity, 90% and specificity, 86.8%). Almost identical cutoff points were observed when using ultrasound global assessment as the reference standard: using 18.2 dB to differentiate mild versus moderate activity yielded sensitivity of 89.2% and specificity of 90.9% and using 22.9 dB to differentiate moderate versus severe activity yielded sensitivity of 89.5% and specificity of 83.1%. CONCLUSION: Quantitative CEUS parameters integrated into inflammatory assessments with ultrasound reduce indeterminate results and improve disease activity level determinations.

Intestinal ultrasound in inflammatory bowel disease.

Intestinal ultrasound (IUS) is non-invasive, fast, cheap, and well-tolerated and requires no preparation and is thus applicable as a point-of-care monitoring tool of inflammatory bowel disease (IBD). Evidence suggests that IUS is comparable to other standard monitoring modalities, i.e., endoscopy, MRI, calprotectin, and C-reactive protein and might be more accurate in predicting response to treatment at an early stage consequently allowing for timely optimised treatment. This review finds that integrating IUS as the standard of care in every IBD outpatient clinic and as the primary outcome in future medical trials seems inevitable.

Classifying Inflammation on Intestinal Ultrasound Images and Cineloops - A Learning Curve Study.

BACKGROUND AND AIMS: Intestinal ultrasound has become a crucial tool for assessing inflammation in patients with inflammatory bowel disease, prompting a surge in demand for trained sonographers. While educational programs exist, the length of training needed to reach proficiency in correctly classifying inflammation remains unclear. Our study addresses this gap partly by exploring the learning curves associated with the deliberate practice of sonographic disease assessment, focusing on the key disease activity parameters of bowel wall thickness, bowel wall stratification, color Doppler signal, and inflammatory fat. METHODS: Twenty-one novices and six certified intestinal ultrasound practitioners engaged in an 80-case deliberate practice online training program. A panel of three experts independently graded ultrasound images representing various degrees of disease activity and agreed upon a consensus score. We used statistical analyses, including mixed-effects regression models, to evaluate learning trajectories. Pass/fail thresholds distinguishing novices from certified practitioners were determined through contrasting-groups analyses. RESULTS: Novices showed significant improvement in interpreting bowel wall thickness, surpassing the pass/fail threshold, and reached mastery level by case 80. For color Doppler signal and inflammatory fat, novices surpassed the pass/fail threshold but did not achieve mastery. Novices did not improve in assessing bowel wall stratification. CONCLUSIONS: We found considerable individual and group-level differences in learning curves supporting the concept of competency-based training for assessing bowel wall thickness, color Doppler signal and inflammatory fat. However, despite practice over 80 cases, novices did not improve in their interpretation of bowel wall stratification, suggesting that a different approach is needed for this parameter.

Early intestinal ultrasound in severe ulcerative colitis identifies patients at increased risk of 1-year treatment failure and colectomy.

BACKGROUND AND AIMS: Reliable and easily accessible objective markers of disease activity to predict long-term treatment outcomes in severe ulcerative colitis (UC) are missing. We aimed to investigate if intestinal ultrasound (IUS) might predict long-term outcomes in hospitalized patients with severe UC treated with intravenous corticosteroids. METHODS: Hospitalized patients with severe UC and IUS inflammation (bowel wall thickness (BWT)>3.0mm) starting IV corticosteroids were recruited at three university hospitals in Denmark. IUS was performed before treatment, 48±24 hours (h), 6±1 days, and 3 months after treatment initiation. Time until colectomy or need for new interventions was registered together with Mayo score at 3 months and partial Mayo score (pMayo) at 12-months. Follow-up time was 12 months. RESULTS: Fifty-six patients were included in the final analysis. Forty-five (80%) patients needed intervention, including 9 colectomies, during the 12-month follow-up. After 48±24h: No patient with a BWT<3mm needed a colectomy, p=0.04. BWT≥4mm showed an increased risk of colectomy (odds ratio 9.5 (95%CI 1.5-186), p=0.03), while a BWT≥3mm showed an increased risk of intervention (3.6 (1.1-12.5), p=0.03). A BWT≥4mm resulted in a significantly shorter time until both colectomy, p=0.03, and treatment intensification (mean days 75 (95%CI24-127) vs. 176 (119-233), p=0.005. However, neither IUS parameters nor pMayo score, CRP, hemoglobin, or p-albumin could predict remission at 3- and 12-months. CONCLUSION: BWT assessed at 48h post intravenous corticosteroid initiation in patients hospitalized with severe UC may identify patients with an increased risk of short- and long-term colectomy and predict a more aggressive short-term disease course.

Systematic review: Defining, diagnosing and monitoring small bowel strictures in Crohn's disease on intestinal ultrasound.

BACKGROUND: Stricturing Crohn's disease (CD) occurs most commonly in the terminal ileum and poses a clinical problem. Cross-sectional imaging modalities such as intestinal ultrasound (IUS), computed tomography enterography (CTE), and magnetic resonance enterography (MRE) allow for assessment of the entire bowel wall and associated peri-enteric findings. Radiologic definitions of strictures have been developed for CTE and MRE; their reliability and responsiveness are being evaluated in index development programs. A comprehensive assessment strategy for strictures using IUS is needed. AIMS: To provide a detailed summary of definitions, diagnosis and monitoring of strictures on IUS as well as technical aspects of image acquisition. METHODS: We searched four databases up to 6 January 2024. Two-stage screening was done in duplicate. We assessed risk of bias using QUADAS-2. RESULTS: There were 56 studies eligible for inclusion. Definitions for strictures on IUS are heterogeneous, but the overall accuracy for diagnosis of strictures is high. The capability of IUS for characterising inflammation versus fibrosis in strictures is not accurate enough to be used in clinical practice or trials. We summarise definitions for improvement of strictures on IUS, and discuss parameters for image acquisition and standardisation. CONCLUSIONS: This systematic review is the first step for a structured program to develop a stricture IUS index for CD.

International expert guidance for defining and monitoring small bowel strictures in Crohn's disease on intestinal ultrasound: a consensus statement.

BACKGROUND: Diagnostic imaging using CT enterography, magnetic resonance enterography, and intestinal ultrasound are important tools in evaluating stricturing Crohn's disease. Definitions of strictures have been developed for CT enterography and magnetic resonance enterography. However, expert recommendations for definitions and treatment response of strictures on intestinal ultrasound are not available. The aim of this study was to standardise definitions, diagnosis, and treatment response criteria in small bowel stricturing Crohn's disease on intestinal ultrasound. METHODS: Using modified RAND-University of California Los Angeles Appropriateness Method, a diverse expert panel of 13 gastroenterologists, seven radiologists, and two patient representatives was assembled. A total of 466 statements on definitions and response to therapy of stricturing Crohn's disease on intestinal ultrasound were generated from a systematic review and from expert opinion, with subsequent rating for appropriateness. Two rounds of voting with an interposed survey result discussion were performed. Statements were classified as inappropriate, uncertain, or appropriate based on the median panel rating and degree of disagreement. Appropriateness was rated using a nine-point Likert scale (1 being inappropriate, 9 being highly appropriate). FINDINGS: A naive or anastomotic small bowel Crohn's disease stricture on intestinal ultrasound is defined by the combination of bowel wall thickening, luminal narrowing, and pre-stenotic dilation. Bowel wall thickness is defined as being more than 3 mm. Luminal narrowing is defined as either a luminal diameter reduction of more than 50% in the narrowest area and relative to a normal adjacent bowel loop, or a luminal diameter of less than 1 cm. Pre-stenotic dilation is defined as more than 2·5 cm or an increase in bowel diameter relative to a normal adjacent bowel loop. Definitions for grading hyperaemia, inflammatory fat, wall stratification, intestinal ultrasound machine technical parameters, and image acquisition were also devised. Treatment response of strictures was defined as reduction in stricture length, bowel wall thickening, luminal narrowing, pre-stenotic dilation, and motility abnormalities. INTERPRETATION: To our knowledge, this is the first intestinal ultrasound appropriateness rating exercise conducted for defining, diagnosing, and measuring response to therapy in small bowel stricturing Crohn's disease and informs future clinical use and intestinal ultrasound index development for clinical trials. FUNDING: Leona M and Harry B Helmsley Charitable Trust.

Crohn's Disease Patient Experiences and Preferences With Disease Monitoring: An International Qualitative Study.

Background: Strategies incorporating objective disease monitoring in Crohn's disease (CD), beyond clinical symptoms are important to improve patient outcomes. Little evidence exists to explore patient understanding of CD treatment goals, nor preferences and experiences with monitoring options. This qualitative study aimed to explore patient experiences and preferences of CD monitoring to inform monitoring strategies, improve patient engagement, and optimize a patient-centered approach to care. Methods: This study used a patient-oriented, qualitative descriptive design. Convenience and snowball sampling were used to recruit adult participants diagnosed with CD who had experience with at least 2 types of disease monitoring. Online focus groups were conducted and data were analyzed using thematic analysis. Results: This international study included 37 participants from Australia, Canada, United Kingdom, and the United States. Overall, participants preferred more noninvasive types of monitoring [eg, intestinal ultrasound (IUS)] but were willing to undergo more invasive monitoring (eg, colonoscopy) if required. To improve disease monitoring, participants wanted increased access to IUS, establishment of a patient-centered interdisciplinary team and access to information and self-testing. Participants identified challenges with communication between patients and providers and stressed the importance of participating in shared decision making and being equal team members in their care. Conclusions: It is imperative to incorporate patient-driven preferences into how we can best structure monitoring strategies, to ensure equitable access to those preferred modalities and embrace a shared decision-making approach to disease management in CD.

Biomechanical Properties of Strictures in Crohn's Disease: Can Dynamic Contrast-Enhanced Ultrasonography and Magnetic Resonance Enterography Predict Stiffness?

Strictures and abdominal pain often complicate Crohn's disease (CD). The primary aim was to explore whether parameters obtained by preoperative contrast-enhanced (CE) ultrasonography (US) and dynamic CE MR Enterography (DCE-MRE) of strictures associates with biomechanical properties. CD patients undergoing elective small intestinal surgery were preoperatively examined with DCE-MRE and CEUS. The excised intestine was distended utilizing a pressure bag. Luminal and outer bowel wall cross-sectional areas were measured with US. The circumferential stricture stiffness (Young's modulus E) was computed. Stiffness was associated with the initial slope of enhancement on DCE-MRE (ρ = 0.63, p = 0.007), reflecting active disease, but lacked association with CEUS parameters. For structural imaging parameters, inflammation and stricture stiffness were associated with prestenotic dilatation on US (τb = 0.43, p = 0.02) but not with MRE (τb = 0.01, p = 1.0). Strictures identified by US were stiffer, 16.8 (14.0-20.1) kPa, than those graded as no or uncertain strictures, 12.6 (10.5-15.1) kPa, p = 0.02. MRE global score (activity) was associated with E (ρ = 0.55, p = 0.018). Elastography did not correlate with circumferential stiffness. We conclude that increasing activity defined by the initial slope of enhancement on DCE-MRE and MRE global score were associated with stricture stiffness. Prestenotic dilatation on US could be a potential biomarker of CD small intestinal stricture stiffness.

Early Intestinal Ultrasound Predicts Intravenous Corticosteroid Response in Hospitalised Patients With Severe Ulcerative Colitis.

BACKGROUND AND AIMS: Our aim was to determine if transabdominal intestinal ultrasound changes after 48 ±â€…24 h of intravenous corticosteroids can predict treatment outcomes in hospitalised patients with severe ulcerative colitis. METHODS: We performed a blinded observational multicentre study. Ultrasound parameters were assessed before treatment initiation, after 48 ±â€…24 h, and 6 ±â€…1 days. Treatment response was determined within 7 days by two outcome measures: 1] partial Mayo score reduction; 2] no administration of rescue therapy. RESULTS: Out of 69 recruited patients, 56 were included in the final analysis, with 37 responders. The colon segment with the highest baseline bowel wall thickness was analysed, being the sigmoid in all patients. There was no difference in baseline bowel wall thickness between responders and non-responders in the partial Mayo score outcome. At 48 ±â€…24 h, a significant difference between responders and non-responders was identified in both absolute bowel wall thickness [median 3.1 mm vs 4.9 mm; p <0.0001], absolute reduction [-1.9 mm vs -0.2 mm; p <0.001], and relative reduction [-35.9% vs -4.1%; p <0.0001]. A ≤20% reduction had a sensitivity of 84.2% (95% confidence interval [CI] 60.4, 96.6%) and a specificity of 78.4% [61.8, 90.2%] for determining non-response [area under the curve 0.85]. In the multivariable analysis, a >20% reduction had the highest odds ratio (22.6 [4.2, 201.2]; p = 0.001) for determining response. Similar results were seen for the rescue therapy outcome. CONCLUSIONS: Changes in bowel wall thickness, after 48 ±â€…24 h following intravenous corticosteroid treatment in hospitalised patients with severe ulcerative colitis, identify responders with high accuracy and might be used as an early marker to guide accelerated rescue therapy.

The knowledge and skills needed to perform intestinal ultrasound for inflammatory bowel diseases-an international Delphi consensus survey.

BACKGROUND: Intestinal ultrasound (IUS) is a non-invasive modality for monitoring disease activity in inflammatory bowel diseases (IBD). IUS training currently lacks well-defined standards and international consensus on competency criteria. AIM: To achieve international consensus on what competencies should be expected from a newly certified IUS practitioner. METHODS: A three-round, iterative Delphi process was conducted among 54 IUS experts from 17 countries. Round 1 was a brainstorming phase with an open-ended question to identify the knowledge and skills that experts believe a newly certified IUS practitioner should possess. The experts' suggestions were then organised into statements by a Steering Committee. In round 2, the experts commented upon and rated the statements, which were revised accordingly. In round 3, the experts rated the revised statements. Statements meeting the pre-defined consensus criterion of at least 70% agreement were included in the final list of statements. RESULTS: In total, 858 items were suggested by the experts in the first round. Based on these suggestions, 55 statements were organised into three categories: knowledge, technical skills and interpretation skills. After the second round, 53 revised statements remained. After the final round, a total of 41 statements had achieved consensus. CONCLUSIONS: We established international, expert consensus on the knowledge and skills that should be expected from newly certified IUS practitioners. These consensus statements are the first step towards mastery learning for IUS training. Educators can utilise these statements to design training programmes and evaluate the competencies of trainees before they engage in independent practice.

ECCO-ESGAR Topical Review on Optimizing Reporting for Cross-Sectional Imaging in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The diagnosis and follow up of patients with inflammatory bowel disease [IBD] requires cross-sectional imaging modalities, such as intestinal ultrasound [IUS], magnetic resonance imaging [MRI] and computed tomography [CT]. The quality and homogeneity of medical reporting are crucial to ensure effective communication between specialists and to improve patient care. The current topical review addresses optimized reporting requirements for cross-sectional imaging in IBD. METHODS: An expert consensus panel consisting of gastroenterologists, radiologists and surgeons convened by the ECCO in collaboration with ESGAR performed a systematic literature review covering the reporting aspects of MRI, CT, IUS, endoanal ultrasonography and transperineal ultrasonography in IBD. Practice position statements were developed utilizing a Delphi methodology incorporating two consecutive rounds. Current practice positions were set when ≥80% of the participants agreed on a recommendation. RESULTS: Twenty-five practice positions were developed, establishing standard terminology for optimal reporting in cross-sectional imaging. Assessment of inflammation, complications and imaging of perianal CD are outlined. The minimum requirements of a standardized report, including a list of essential reporting items, have been defined. CONCLUSIONS: This topical review offers practice recommendations to optimize and homogenize reporting in cross-sectional imaging in IBD.

Defining Transabdominal Intestinal Ultrasound Treatment Response and Remission in Inflammatory Bowel Disease: Systematic Review and Expert Consensus Statement.

BACKGROUND AND AIMS: No consensus exists on defining intestinal ultrasound response, transmural healing, or transmural remission in inflammatory bowel disease, nor clear guidance for optimal timing of assessment during treatment. This systematic review and expert consensus study aimed to define such recommendations, along with key parameters included in response reporting. METHODS: Electronic databases were searched from inception to July 26, 2021, using pre-defined terms. Studies were eligible if at least two intestinal ultrasound [IUS] assessments at different time points during treatment were reported, along with an appropriate reference standard. The QUADAS-2 tool was used to examine study-level risk of bias. An international panel of experts [n = 18] rated an initial 196 statements [RAND/UCLA process, scale 1-9]. Two videoconferences were conducted, resulting in additional ratings of 149 and 13 statements, respectively. RESULTS: Out of 5826 records, 31 full-text articles, 16 abstracts, and one research letter were included; 83% [40/48] of included studies showed a low concern of applicability, and 96% [46/48] had a high risk of bias. A consensus was reached on 41 statements, with clear definitions of IUS treatment response, transmural healing, transmural remission, timing of assessment, and general considerations when using intestinal ultrasound in inflammatory bowel disease. CONCLUSIONS: Response criteria and time points of response assessment varied between studies, complicating direct comparison of parameter changes and their relation to treatment outcomes. To ensure a unified approach in routine care and clinical trials, we provide recommendations and definitions for key parameters for intestinal ultrasound response, to incorporate into future prospective studies.

Influence of Genetics, Immunity and the Microbiome on the Prognosis of Inflammatory Bowel Disease (IBD Prognosis Study): the protocol for a Copenhagen IBD Inception Cohort Study.

INTRODUCTION: Inflammatory bowel diseases (IBD), encompassing Crohn's disease and ulcerative colitis, are chronic, inflammatory diseases of the gastrointestinal tract. We have initiated a Danish population-based inception cohort study aiming to investigate the underlying mechanisms for the heterogeneous course of IBD, including need for, and response to, treatment. METHODS AND ANALYSIS: IBD Prognosis Study is a prospective, population-based inception cohort study of unselected, newly diagnosed adult, adolescent and paediatric patients with IBD within the uptake area of Hvidovre University Hospital and Herlev University Hospital, Denmark, which covers approximately 1 050 000 inhabitants (~20% of the Danish population). The diagnosis of IBD will be according to the Porto diagnostic criteria in paediatric and adolescent patients or the Copenhagen diagnostic criteria in adult patients. All patients will be followed prospectively with regular clinical examinations including ileocolonoscopies, MRI of the small intestine, validated patient-reported measures and objective examinations with intestinal ultrasound. In addition, intestinal biopsies from ileocolonoscopies, stool, rectal swabs, saliva samples, swabs of the oral cavity and blood samples will be collected systematically for the analysis of biomarkers, microbiome and genetic profiles. Environmental factors and quality of life will be assessed using questionnaires and, when available, automatic registration of purchase data. The occurrence and course of extraintestinal manifestations will be evaluated by rheumatologists, dermatologists and dentists, and assessed by MR cholangiopancreatography, MR of the spine and sacroiliac joints, ultrasonography of peripheral joints and entheses, clinical oral examination, as well as panoramic radiograph of the jaws. Fibroscans and dual-energy X-ray absorptiometry scans will be performed to monitor occurrence and course of chronic liver diseases, osteopenia and osteoporosis. ETHICS AND DISSEMINATION: This study has been approved by Ethics Committee of the Capital Region of Denmark (approval number: H-20065831). Study results will be disseminated through publication in international scientific journals and presentation at (inter)national conferences.

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.

Bowel stiffness associated with histopathologic scoring of stenosis in patients with Crohn's disease.

BACKGROUND AND AIMS: Intestinal stenosis is a common complication of Crohn's Disease (CD). Stenosis is associated with alteration of bowel mechanical properties. This study aims to quantitate the mechanical properties of the intestinal stenosis and to explore associations between histology and mechanical remodeling at stenotic intestinal sites in CD patients. METHODS: Intestinal segments from stenotic sites were studied in vitro from 19 CD patients. A luminal catheter with a bag was used to stepwise pressurize the intestinal segments from 0-100 cmH2O with 10 cmH2O increments. B-mode ultrasound images were obtained at the narrowest part of the stenosis at each pressure level and morphometric parameters were obtained from ultrasound images. The mechanical behavior of the stenotic tissue were characterized by using an isotropic three dimensional strain energy function in Demiray model form, the mechanical constants were obtained by fitting the model to the recorded intraluminal pressure and the inner radius of the stenotic segment of the small bowel. Grading scores were used for histological analysis of inflammation, fibrosis, muscular hypertrophy and adipocyte proliferation in the intestinal layers. The collagen area fraction in intestinal layers was also calculated. Associations between histological and the mechanical constants (stiffness) were analyzed. RESULTS: Chronic inflammation was mainly located in mucosa whereas fibrosis was found in submucosa. The mechanical remodeling was performed with changed mechanical constants ranged between 0.35-13.68kPa. The mechanical properties changes were associated mainly with chronic inflammation, fibrosis and combination of inflammation and fibrosis (R>0.69, P<0.001). Furthermore, the mechanical properties correlated with the collagen fraction in submucosa and muscular layers (R>0.53, P<0.05). CONCLUSIONS: We quantitated the intestinal stenosis stiffness. Associations were found between bowel mechanical remodeling and histological changes at the stenotic site in CD patients. STATEMENT OF SIGNIFICANCE: Although intestinal ultrasonography, CT and MRI can be used to diagnose Crohn's Disease (CD)-associated bowel strictures, these techniques may not have sufficient accuracy and resolution to differentiate predominantly inflammatory strictures from predominantly fibrotic strictures. The present study aims to quantitate the mechanical remodeling of intestinal stenosis and to explore the associations between histological parameters and mechanical properties at the intestinal stenotic sites in CD patients. For the first time, we quantitatively demonstrated that the mechanical properties of the intestinal wall in CD stenosis are associated with the chronic inflammation, fibrosis and collagen fraction in the intestinal layers. The results of this study may facilitate design and development of artificial biomaterials for gastrointestinal organs. The potential clinical implication of this study is that the histological characteristics in patients with CD can be predicted clinically by means of inflammation and fibrosis assessment in conjunction with tissue stiffness measurement.