Expert Consensus on Optimal Acquisition and Development of the International Bowel Ultrasound Segmental Activity Score [IBUS-SAS]: A Reliability and Inter-rater Variability Study on Intestinal Ultrasonography in Crohn's Disease

Role of noncontrast enhanced abdominal ultrasound in the diagnostic assessment of pediatric inflammatory bowel disease

OBJECTIVES

Assessment of small bowel involvement when diagnosing inflammatory bowel disease (IBD) delineates clinical subtype and disease extension. The gold standard for small bowel assessment is magnetic resonance enterography (MRE), but MRE is not always feasible for children. Standard, non-contrast enhanced abdominal ultrasound is an acceptable alternative. The study aimed to evaluate the utility of ultrasound in the diagnostic work-up of pediatric IBD to identify small bowel involvement.

METHODS

A retrospective study was conducted among children (< 18 years) who had abdominal ultrasound during assessment for IBD (2019-2023) at Christchurch Hospital, New Zealand. Descriptive analysis compares small bowel ultrasound to MRE, endoscopy and histology.

RESULTS

The cohort comprised 47 children, mean age 9.9 years (± 4.1), 23 (49%) males and 42 (89%) with Crohn's disease. All had endoscopy and histology data available for comparison, and 26 had MRE. Fourteen (30%) had no small bowel disease on ultrasound, MRE, endoscopy, or histology. Ultrasound confirmed small bowel disease diagnosed by other modalities for 12 (26%). Ultrasound identified small bowel disease for 7 (15%) that had not been seen during the diagnostic process by MRE, endoscopy or histology, possibly due to the limitations of endoscopy and time-delays between diagnosis and MRE. Small bowel disease was not picked up on ultrasound for 14 (30%) children, disease locations being duodenum (n = 6), TI (n = 5), proximal ileum (n = 3), and jejunum (n = 2).

CONCLUSIONS

Abdominal ultrasound is a valuable resource for assessing disease extent in suspected pediatric IBD. This study highlights the clinical benefit and feasibility of a multi-modal diagnostic approach.

The effects of probiotic treatment with Bifidobacterium breve, Bif195 for small intestinal Crohn's disease and the gut microbiome: results from a randomised, double-blind, placebo-controlled trial

BACKGROUND

The aetiology of Crohn's disease, a chronic inflammatory bowel disease, is multifactorial and not completely understood. However, the association with gut dysbiosis is well-established, and manipulation of the gut microbiota has gained interest as a treatment strategy. This study aimed to investigate the effects of the probiotic strain Bifidobacterium breve, Bif195™ (Bif195) on intestinal inflammation, symptoms, and the gut microbiome composition in patients with small intestinal Crohn's disease.

METHODS

This was a randomised, double-blind, placebo-controlled trial. Thirty-three patients with small intestinal Crohn's disease were assigned to eight weeks of treatment with Bif195 or placebo (1:1). The primary outcome was changes in bowel wall thickness measured by intestinal ultrasonography. Other outcomes were changes in symptom severity, quality of life, faecal calprotectin, fatigue, and specific inflammatory parameters on ultrasonography. Changes in the microbiome composition were also examined.

RESULTS

Bif195 did not affect the bowel wall thickness in the small intestine compared to placebo. Nor did we observe effects on secondary or clinical explorative outcomes. Analysis of the gut microbiome showed that the relative abundance of B. breve rose during the intervention in the Bif195 group, but the result was statistically non-significant. Surprisingly, we observed a clustering of baseline microbiome data into two groups that differed in several aspects including a statistically significant difference in the incidence of previous bowel resections among the participants. Furthermore, changes in symptom scores after eight weeks of intervention were significantly different across the two microbiome groups, with an interaction effect of p = 0.04.

CONCLUSIONS

Eight weeks of treatment with Bif195 did not affect clinical outcomes for Crohn's disease. However, variations in baseline microbiome data influenced the results. This underscores the importance of assessing baseline microbiome data in intervention studies in Crohn's disease.

CLINICALTRIALS

gov NCT04842149.

Clinical Trial: The Effects of Emulsifiers in the Food Supply on Disease Activity in Crohn's Disease: An Exploratory Double-Blinded Randomised Feeding Trial

BACKGROUND

Advice to avoid dietary emulsifiers in Crohn's disease (CD) is based on preclinical data.

AIMS

To examine the effect of diets high (HED) and low (LED) in emulsifiers in the food supply on disease activity in CD.

METHODS

In a double-blinded, randomised feeding study, we randomised adults with symptomatic, sonographically active CD with ileal involvement on ≥ 2 months' stable medical therapy to 4 weeks of a HED or LED modelled on Australian healthy eating guidelines. We measured the Harvey-Bradshaw Index (HBI), sonographic indices (IBUS-SAS, bowel wall thickness), quality of life (QOL) and fatigue at baseline and study completion.

RESULTS

We randomised 24 patients, mean age 37 (95% CI 32, 41) years, 12 male, HBI 6 (6, 8), bowel wall thickness 6.0 (5.5-6.6) mm. Adherence was > 95%. Clinical remission (HBI < 5) occurred in 9/12 on HED and 7/12 on LED; 2 and 3, respectively, withdrew early with increasing gastrointestinal symptoms. IBUS-SAS fell from 51 (35, 68) to 33 (15, 51) on HED (p = 0.014) and from 57 (38, 76) to 44 (29, 59) on LED (p = 0.01). Bowel wall thickness reduced by 34% on HED and 15% on LED in those who completed the study. QOL and fatigue improved on both diets (p ≤ 0.05). There were no statistically significant differences in outcomes between diets.

CONCLUSIONS

In the context of a healthy diet, the emulsifier content had no influence over disease activity over 4 weeks in patients with CD. Recommendations to avoid emulsifiers in patients with active CD are not supported. Australian New Zealand Clinical Trials Registry (ACTRN12619001099112).

The Essential Role of Imaging in the Diagnosis, Characterization, and Treatment of Patients with Crohn's Disease

Imaging is essential in assessing patients with Crohn's disease, and it provides important and complementary information to the clinical and endoscopic findings. Patients can be accurately phenotyped and complications identified.

Quantitative intestinal ultrasound color doppler vessel density in children and young adults with Crohn's disease: Correlation with modified Limberg score and contrast-enhanced ultrasound parameters

What is Known

What is New

Accuracy of superb microvascular imaging (SMI) in predicting endoscopic Crohn's disease activity

BACKGROUND

Treat-to-target therapy in inflammatory bowel disease requires longitudinal assessment of disease activity and intestinal ultrasound (IUS) is a promising non-invasive and cheap technology to provide objective read-outs. Vascularization of the bowel wall is one key parameter on IUS. While this is conventionally done with Color doppler imaging, it is currently unclear whether microvascular flow imaging techniques might improve the diagnostic performance of IUS.

AIMS

To explore the utility of superb microvascular imaging (SMI) for assessing disease activity in Crohn's disease (CD).

METHODS

We performed a prospective single-center cross-sectional cohort study including 56 patients with CD. IUS was performed on the terminal ileum or sigmoid colon within 30 days of colonoscopy and the International Bowel Ultrasound (IBUS) group Segmental Activity Score (SAS) as well as SMI signals were determined and correlated to established endoscopic, clinical and biochemical read-outs of disease activity.

RESULTS

SMI scores showed superior correlation to endoscopic disease activity than Doppler imaging scores. While this did not further improve the diagnostic performance of the composite IBUS-SAS, SMI scores as a single parameter excellently predicted segmental endoscopic disease activity.

CONCLUSIONS

SMI is a highly promising tool to improve or simplify the non-invasive assessment of disease activity in CD that should further be investigated in real-world and multi-center trials.

A comparison between the Bowel Ultrasound Score and International Bowel Ultrasound Segmental Activity Score based on ileocolonoscopy in patients with Crohn's disease

BACKGROUND AND AIM

We aimed to compare two main existing scores, the Bowel Ultrasound Score (BUSS) and the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) to predict simplified endoscopic activity score for Crohn's disease (SES-CD).

METHODS

A cross-sectional study was conducted to evaluate the disease activity in Crohn's disease (CD) patients with ileal involvement between November 2019 and February 2024. Endoscopic remission for CD was accepted as SES-CD ≤2.

RESULTS

A total of 56 adult patients with CD (male: 38, 68%, median age: 40.5 years) were included in the study, the median duration of the disease was 8.4 years. The cutoff value for BUSS to determine endoscopic remission was 3.9, whereas the cutoff value for IBUS-SAS to establish endoscopic remission was 24.4. BUSS and SES-CD had a strong positive correlation (P < 0.001), BUSS and IBUS-SAS had a high positive correlation (P < 0.001), and BUSS and C-reactive protein had a slightly positive correlation (P < 0.001).

CONCLUSION

This study revealed that the cutoff values for BUSS and IBUS-SAS in CD patients with endoscopic remission were 3.9 and 24.4, respectively. Furthermore, it was demonstrated that BUSS and IBUS-SAS highly correlate with endoscopic activity in the real-world cohort.

Intestinal Ultrasound Findings and Their Prognostic Value in Early Crohn's Disease - a Copenhagen IBD Cohort Study

BACKGROUND & AIMS

We characterize the sonographic features of Crohn's disease at diagnosis and evaluate the prognostic value of intestinal ultrasound during the early stage of disease.

METHODS

A prospective, population-based cohort of patients with newly diagnosed Crohn's disease were followed with intestinal ultrasound in conjunction with symptomatic, biochemical, and endoscopic evaluations.

RESULTS

Between May 2021 and April 2023, 201 patients with adult-onset Crohn's disease were recruited. No associations were found between sonographic inflammation at diagnosis and diagnostic delay. After 3 months, transmural remission was achieved in 38% of patients, with patients with colonic disease achieving transmural remission more often. Transmural remission at 3 months was significantly associated with steroid-free clinical remission at 3 months and all subsequent follow-ups within the first year. Transmural remission was also associated with a lower risk of treatment escalation during follow-up until 12 months (26% vs 53%; P = .003). At 12 months, 41% had achieved transmural remission. Higher baseline body mass index negatively impacted the likelihood of 12-month transmural remission significantly (overweight: odds ratio [OR], 0.34; 95% confidence interval [CI],0.12-0.94; obese: OR, 0.16; 95% CI, 0.04-0.73). The International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) in the terminal ileum at diagnosis was the best predictor of ileocecal resection during the first year, with an optimal threshold of 63 (area under the curve [AUC], 0.92; sensitivity, 100%; specificity, 73%).

CONCLUSIONS

Transmural remission is an achievable outcome target for many patients with newly diagnosed Crohn's disease and is associated with a favorable clinical outcome, including sustained steroid-free clinical remission. Further, intestinal ultrasound findings at diagnosis predict future ileocecal resection.

Superb Microvascular Imaging Is Superior to Doppler Imaging in Ruling Out Ulcerative Colitis Disease Activity

BACKGROUND

There is an unmet medical need for noninvasive techniques to determine disease activity in inflammatory bowel disease (IBD) and intestinal ultrasound (IUS) has shown promising performance in this regard. In addition to parameters such as bowel wall thickness, stratification, and mesenteric fat, color Doppler signals are used to determine inflammatory activity in the gut. However, whether superb microvascular imaging (SMI), a microvascular flow imaging technique, improves the diagnostic accuracy is currently unclear.

METHODS

We performed a prospective single-center cross-sectional cohort study including 62 patients with ulcerative colitis (UC). IUS was performed on the sigmoid colon within 30 days of colonoscopy and the International Bowel Ultrasound (IBUS) group Segmental Activity Score (SAS) as well as SMI signals were determined and correlated to established endoscopic, clinical, and biochemical read-outs of disease activity.

RESULTS

Semiquantitative scoring of SMI signals had a substantial interobserver agreement between 2 blinded and expert central readers. It showed excellent correlation to endoscopic, clinical, and biochemical disease activity. While SMI did not improve the overall diagnostic performance of the IBUS-SAS to predict endoscopic disease activity, SMI alone was highly precise and superior to Doppler imaging in predicting endoscopic remission.

CONCLUSIONS

IUS is a highly precise noninvasive diagnostic tool to monitor disease activity in UC, in particular for predicting endoscopic remission. Assessing the SMI signals in the bowel wall of patients with IBD seems a promising tool to simplify IUS diagnostics in IBD that warrants further research.

Understanding the Learning Curve of Intestinal Ultrasound in Inflammatory Bowel Disease: A Comparative Study Between Novice, Regular and Expert

BACKGROUND

Intestinal ultrasound (IUS) has emerged as a valuable tool for monitoring inflammatory bowel disease (IBD), but its reliability depends on the technical skills of the operator.

AIMS

This study aimed to assess the IUS learning curve of a novice briefly trained to get him familiarized with the ultrasound machine and normal/abnormal IUS images, and a gastroenterologist with formal general ultrasound training and regular IUS experience (>200 exams), using an expert radiologist as the gold standard.

METHODS

The ULTRA-IBD study was a single-center, prospective study involving 50 consecutive IBD patients. Three successive IUS examinations were performed on each patient by the 3 operators. Inter-rater agreement on IUS disease activity was calculated using the intraclass correlation coefficient.

RESULTS

The experienced gastroenterologist demonstrated consistently good agreement with the radiologist throughout the study, while the novice failed to go beyond poor agreement after 50 examinations, although a faster learning curve was observed in patients without history of IBD surgery.

CONCLUSION

These findings highlight the difficulty of the technical performance of IUS rather than its interpretation. Comprehensive ultrasound training beforehand and between 50 and 200 examinations of experience are necessary before embarking on IUS.

Comparative analysis of enteroscopy, computed tomography enterography, and intestinal ultrasound for the evaluation of small bowel Crohn's disease

Background

The comparable evaluation of computed tomography enterography (CTE), enteroscopy, and intestinal ultrasound in small bowel Crohn's disease (CD) is imprecise.

Objectives

The purpose of this study was to analyze the findings of enteroscopy, CTE, and intestinal ultrasound to determine the advantages and disadvantages of each method for the evaluation of small bowel CD.

Design

It was a single-center, observational, retrospective study.

Methods

The differences in localization of disease lesions, mucosal inflammation, and transmural inflammation between enteroscopy, CTE, and intestinal ultrasound for evaluation of small bowel CD were compared.

Results

A total of 198 patients with small bowel CD were included in the analysis. CTE and intestinal ultrasound had a lower detection rate of upper intestinal lesions compared with enteroscopy (p < 0.05). Enteroscopy was better than CTE and intestinal ultrasound in the detection of stenosis (p < 0.001), and the assessment of fistula by CTE was better than that by enteroscopy and intestinal ultrasound (p < 0.05). Enteroscopy, CTE, and intestinal ultrasound differed in the assessment of inflammatory activity, and the agreement of the three methods was poor (all intra-class correlation coefficient <0.75).

Conclusion

Enteroscopy is superior to CTE and intestinal ultrasound for the assessment of upper intestinal CD lesions. Enteroscopy, CTE, and intestinal ultrasound were not consistent in evaluating inflammatory activity, and the three methods may need to be combined for an accurate assessment.

Quantitative assessment of transmural remission in Crohn's disease using low dose computed tomography (CT) enterography perfusion imaging: a single-centre study based on intestinal microcirculation

AIM

To assess transmural remission in patients with Crohn's disease using low-dose small bowel computed tomography (CT) perfusion scans.

MATERIALS AND METHODS

Forty six patients were divided into active and remission phases based on Crohn's Disease Activity Index (CDAI) and C-reactive protein (CRP). Dual-source CT enterography with low-dose perfusion scans was conducted to generate perfusion parameter maps, including blood flow (BF), blood volume (BV), time to peak (TTP), mean transit time (MTT), and permeability of surface (PS). We compared differences in perfusion parameter values of intestinal walls, mesenteric fat, and lymph nodes between two groups. Receiver operating characteristic (ROC) curves were plotted, and area under the curve (AUC), sensitivity, specificity, and cutoff values were calculated.

RESULTS

The BF, BV, TTP, MTT, and PS values of the intestinal wall were significantly higher in the active phase (P0.05). Additionally, lymph node BF and TTP displayed significant differences (P<0.01).

CONCLUSION

Dual-source CT enterography with low-dose perfusion scans enables quantitative assessment of Crohn's disease microcirculation in intestinal walls, mesenteric fat, and lymph nodes. These quantitative indicators provide strong diagnostic efficacy and offer insights into whether the disease is in transmural remission.

Determining the Accuracy and Interobserver Agreement of 4 Ultrasound Scores in Crohn's Disease Assessment: Correlations With Endoscopy

INTRODUCTION

Gastrointestinal ultrasound (GIUS) is recommended for monitoring Crohn's disease (CD). GIUS scores are used to quantify CD activity. Among them, International Bowel Ultrasound Segmental Activity Score (IBUS-SAS), Bowel Ultrasound Score (BUSS), Simple Ultrasound Score, and Simple Ultrasound Score for Crohn's Disease are most commonly used. The aim of this study was to compare and correlate the performance of such indicators with endoscopic activity and to calculate interobserver agreement.

METHODS

Consecutive patients with CD at our hospital between June 2015 and July 2021 were retrospectively enrolled. All patients underwent ileocolonoscopy after medical treatment. GIUS was performed within 2 weeks, and 4 GIUS scores were independently calculated. Receiver operating characteristic curve analyses were used to determine a cutoff value. Cohen kappa (κ) coefficient was calculated to estimate the agreement between GIUS findings.

RESULTS

A total of 106 patients with CD were enrolled. 80.2% (85/106) were endoscopic active (Simple Endoscopic Score for Crohn's disease ≥3), and 8.49% (9/106) were severe cases (Simple Endoscopic Score for Crohn's disease ≥9). All GIUS features (bowel wall thickness, color Doppler signs, bowel wall stratification, inflammatory signals at the mesentery) were statistically significant in assessing CD activity ( P < 0.05). IBUS-SAS showed the highest area under the curve (0.98; 95% CI: 0.96-1.00) and specificity (95.2%) for a cutoff value of 46.50. However, IBUS-SAS had only moderate agreement (Cohen κ = 0.427; P < 0.001). BUSS had substantial interobserver agreement (Cohen κ = 0.947; P < 0.001), with a similar diagnostic value (sensitivity, 100.0%; accuracy, 95.3%; area under the curve of 0.96 [95% CI: 0.91-1.00] for a cutoff value of 4.58).

DISCUSSION

GIUS score is an efficient and reliable method to assess CD activity. BUSS achieved a high accuracy and excellent interobserver agreement, which is more suitable for treatment assessment.

Point-of-Care Ultrasound in Gastroenterology and Hepatology

Point-of-care ultrasound (POCUS) is changing the practice of nearly all specialties and is increasingly being incorporated as a bedside tool by more gastroenterologists and hepatologists. POCUS is most often used to answer focused diagnostic questions, supplement the traditional physical examination, and guide performance of invasive bedside procedures. This review describes several common POCUS applications used in gastroenterology and hepatology, as well as some novel applications that warrant further investigation.

[Imaging in chronic inflammatory bowel disease]

In patients with chronic inflammatory bowel disease (IBD), endoscopic techniques (including capsule techniques and balloon enteroscopy for the small intestine), ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) are primarily used as often complementary imaging techniques. Radiation exposure needs to be kept in mind when using CT and conventional X‑ray-techniques. Therefore, most importantly, ultrasound and MRI have changed the routine diagnostics of intestinal diseases. US, CT and MRI not only assess the lumen but, similarly importantly, also the wall and the surrounding structures of the gastrointestinal tract. Furthermore, functional processes can be visualized and provide important information about passage and perfusion, which is mainly true for real-time ultrasound. CT and MRI are usually carried out with the use of contrast agents as contrast-enhanced CT (CECT) and contrast-enhanced MRI (CEMRI). Ultrasound is performed conventionally or with intravascular (CEUS) and/or extravascular intracavitary contrast agent application (icCEUS). This article provides an overview of the current significance of the mentioned imaging procedures in patients with IBD and discusses the typical indications.

Advancing therapeutic frontiers: a pipeline of novel drugs for luminal and perianal Crohn's disease management

Crohn's disease (CD) is a chronic, complex inflammatory disorder of the gastrointestinal tract that presents significant therapeutic challenges. Despite the availability of a wide range of treatments, many patients experience primary non-response, secondary loss of response, or adverse events, limiting the overall effectiveness of current therapies. Clinical trials often report response rates below 60%, partly due to stringent inclusion criteria. Emerging therapies that target novel pathways offer promise in overcoming these limitations. This review explores the latest investigational drugs in phases I, II, and III clinical trials for treating both luminal and perianal CD. We highlight promising therapies that target known mechanisms, including selective Janus kinase inhibitors, anti-adhesion molecules, tumor necrosis factor inhibitors, and IL-23 selective inhibitors. In addition, we delve into novel therapeutic strategies such as sphingosine-1-phosphate receptor modulators, miR-124 upregulators, anti-fractalkine (CX3CL1), anti-TL1A, peroxisome proliferator-activated receptor gamma agonists, TGFBRI/ALK5 inhibitors, anti-CCR9 agents, and other innovative small molecules, as well as combination therapies. These emerging approaches, by addressing new pathways and mechanisms of action, have the potential to surpass the limitations of existing treatments and significantly improve CD management. However, the path to developing new therapies for inflammatory bowel disease (IBD) is fraught with challenges, including complex trial designs, ethical concerns regarding placebo use, recruitment difficulties, and escalating costs. The landscape of IBD clinical trials is shifting toward greater inclusivity, improved patient diversity, and innovative trial designs, such as adaptive and Bayesian approaches, to address these challenges. By overcoming these obstacles, the drug development pipeline can advance more effective, accessible, and timely treatments for CD.

Intestinal Ultrasound Measures are Strongly Correlated With Small Bowel Endoscopic Lewis Score in Active Crohn's Disease

BACKGROUND

Small bowel video capsule endoscopy (SB-VCE) assesses mucosal inflammation in Crohn's disease (CD), while intestinal ultrasound (IUS) examines transmural involvement. We aimed to correlate SB-VCE with IUS in evaluating active CD and monitoring treatment response over time.

METHODS

Patients with active SB-CD who initiated biologics were prospectively followed with fecal calprotectin (FC), SB-VCE, and IUS at baseline and after 14 and 52 weeks. The Lewis score (LS), Limberg index (LI), and terminal ileum bowel wall thickness (TI-BWT) were documented, and the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) was retrospectively calculated. Biochemical, endoscopic, and ultrasonographic remission were defined as FC < 150 μg/g, LS < 135, and LI < 2 + TI-BWT ≤ 3 mm, respectively. A therapeutic response for each index was defined as a 25% reduction compared to baseline.

RESULTS

Seventy-one patients were included (median age: 30 years [23-43], 49.3% male). The median interval between SB-VCE and IUS was 3 days (0-25). Initially, the LS strongly correlated with TI-BWT (r = 0.647, P < .001), LI (r = 0.597, P < .001), and IBUS-SAS (r = 0.647, P < .001), but these correlations weakened over time (TI-BWT: r = 0.344, P = .002; LI: r = 0.471, P = .001; IBUS-SAS: r = 0.236, P = .122). Moderate agreement was found between ultrasonographic and endoscopic treatment responses (LS and TI-BWT: K = 0.51, P = .015; LS and LI: K = 0.44, P = .063), with fair agreement for remission (K = 0.27, P = .006). TI-BWT best cutoffs for mild (LS ≥ 135) and moderate-to-severe (LS ≥ 790) inflammation were 2.25 mm and 3.6 mm, respectively.

CONCLUSIONS

IUS measures are strongly correlated with VCE-inflammatory LS in active CD and may provide an assessment of endoscopic response and remission over time.

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.

Review article: Measuring disease severity in inflammatory bowel disease - Beyond treat to target

BACKGROUND

Inflammatory bowel disease (IBD) follows a heterogenous disease course and predicting a patient's prognosis is challenging. There is a wide burden of illness in IBD and existing tools measure disease activity at a snapshot in time. Comprehensive assessment of IBD severity should incorporate disease activity, prognosis, and the impacts of disease on a patient. This review investigates the concept of disease severity in adults with IBD to highlight key components contributing to this.

METHODS

To perform this narrative review, a Medline search was conducted for full-text articles available at 1st March 2024 using search terms which encompassed disease activity assessment, disease severity, prognosis, natural history of Crohn's disease (CD) and ulcerative colitis (UC), and the burden of IBD.

RESULTS

Current methods of disease assessment in IBD have evolved from a focus on the burden of symptoms to one that includes inflammatory targets, genetic, serological, and proteomic profiles, and assessments of quality-of-life (QoL), disability, and psychosocial health. Longitudinal studies of IBD suggest that the burden of illness is driven by disease phenotype, clinical markers of complicated disease course (previous intestinal resection, corticosteroid use, perianal disease in CD, recent hospitalisations in UC), gut inflammation, and the impact of IBD on the patient.

CONCLUSIONS

Disease severity in IBD can be difficult to conceptualise due to the multitude of factors that contribute to IBD outcomes. Measurement of IBD severity may better encapsulate the full burden of illness rather than gut inflammation alone at a single timepoint and may be associated with longitudinal outcomes.

Baseline and Postinduction Intestinal Ultrasound Findings Predict Long-term Transmural and Mucosal Healing in Patients With Crohn's Disease

BACKGROUND

Intestinal ultrasound (IUS) is becoming a standard assessment tool in Crohn's disease (CD), but limited data exist on its ability to predict long-term objective outcomes. Therefore, we aimed to investigate the predictive value of IUS findings for long-term transmural healing (TH) and mucosal healing (MH) in CD.

METHODS

We prospectively included consecutive CD patients with active endoscopic disease and bowel wall thickness (BWT) >3.0 mm, initiating infliximab. Intestinal ultrasound parameters (ie, BWT, inflammatory mesenteric fat [i-fat], bowel blood flow and stratification) and International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) were collected at baseline, after 14 to 26 weeks (visit 1, postinduction) and 44 to 56 weeks (visit 2). Transmural healing (normalization of all IUS parameters) and MH (SES-CD ≤2) were assessed at visit 2.

RESULTS

One hundred twenty-nine patients were evaluated. At visit 2, 38.0% and 48.1% of patients achieved TH and MH, respectively. All the IUS parameters and IBUS-SAS showed improvement at visit 1 and visit 2 compared with the baseline (all P < .001). Multivariable analysis found that presence of i-fat at baseline (odds ratio [OR], 0.57; P = .008) and greater postinduction BWT (OR, 0.24; P < .001) were negative predictors for TH, while higher baseline (OR, 0.98; P = .013) and postinduction (OR, 0.94; P < .001) IBUS-SAS predicted negatively for MH. Postinduction BWT <4.5mm best predicted TH (AUC 0.85; P < .001), while postinduction IBUS-SAS <25.0 best predicted MH (AUC 0.82; P < .001). Moreover, colonic disease was associated with higher risk of TH (OR, 2.55; P = .027), and disease duration >24 months with lower risk of MH (OR, 0.27; P = .006).

CONCLUSIONS

Baseline and postinduction IUS findings reliably predict long-term TH and MH in patients with CD receiving infliximab.

Transabdominal intestinal ultrasound and its parameters used in the assessment of pediatric inflammatory bowel disease

This article extends on the use of transabdominal intestinal ultrasound in diagnosing pediatric inflammatory bowel disease. Some of the more essential features used in assessing bowel inflammation, such as hyperemia and wall thickness on ultrasound, are expanded upon from the publication on imaging and endoscopic tools in pediatric inflammatory bowel disease.

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

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

AGA Clinical Practice Update on the Role of Intestinal Ultrasound in Inflammatory Bowel Disease: Commentary

DESCRIPTION

In the past 3 years, the use of intestinal ultrasound (IUS) for monitoring inflammatory bowel disease in clinical practice has grown substantially in the United States. This American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) aims to review the available evidence and guidance regarding the role of intestinal ultrasound in inflammatory bowel disease care.

METHODS

This CPU was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Clinical Gastroenterology and Hepatology. This expert commentary incorporates important and recently published studies in this field, and it reflects the experiences of the multidisciplinary group of authors composed of adult and pediatric gastroenterologists.

Intestinal Ultrasound: Envisioning a New Future for Crohn's Disease Management

The use of intestinal ultrasound (IUS) in the clinical assessment of intestinal disorders remains in its infancy in North America. We present a case in which IUS was used as a complement to Crohn's disease treatment in a 19-year-old man. After endoscopy and diagnosis, IUS was employed alongside other investigations to elucidate the extent of disease activity. It allowed identification and monitoring of complications such as free fluid and mucosal inflammation. IUS provided a marker of disease activity, even during apparent clinical remission. This case demonstrates that IUS can enhance disease monitoring and inform direction of therapy.

Endoscopic Skipping, Stricturing, and Penetrating Complications in Crohn's Disease on Tandem Ileo-colonoscopy and Cross-sectional Imaging: A Retrospective Cohort Study

BACKGROUND

Crohn's disease (CD) is characterized by discontinuous inflammation. Failure to identify skipping lesions of the terminal ileum (TI) or transmural changes can lead to incorrect management.

METHODS

Eligible adult patients with CD undergoing ileo-colonoscopy and computed tomography enterography or magnetic resonance enterography within 6 months. We determined the prevalence of endoscopic skipping (normal ileum on colonoscopy but proximal small bowel inflammation on cross-sectional imaging), skip lesions (discontinuous inflammation along the gastrointestinal tract identified on cross-sectional imaging), structuring, and penetrating complications.

RESULTS

Among 202 patients, 45 (22.3%) had endoscopic skipping proximal to TI intubation. Fifty patients (24.5%) had small bowel skip lesions, primarily in the ileum. Strictures were identified in 34 patients (16.8%) through both imaging and ileo-colonoscopy, in 21 patients (10.4%) solely through cross-sectional imaging, and in 3 patients (1.5%) solely through ileo-colonoscopy. Approximately 36.2% of stricturing cases would be missed without cross-sectional imaging. Penetrating complications, including abscesses (2.5%) and various fistula types (4.9%), were detected in 15 (7.4%) patients.

CONCLUSIONS

Ileo-colonoscopy missed detection of active CD in approximately one-fifth of cases due to more proximal disease location. Stricturing disease might be missed in more than a third of cases if cross-sectional imaging is not performed.

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.

Assessment of perianal fistulizing Crohn's disease activity with endoanal ultrasound: A retrospective cohort study

BACKGROUND

Perianal fistulas pose dual challenges to Crohn's disease (CD) patients. Low patient compliance due to the complexity of existing examination methods plagues the treatment and follow-up management of perianal CD.

AIM

To determine the accuracy of endoanal ultrasound (EUS) and shear wave elastography (SWE) for evaluating perianal fistulizing CD (PFCD) activity.

METHODS

This was a retrospective cohort study. A total of 67 patients from August 2022 to December 2023 diagnosed with CD were divided into three groups: Non-anal fistula group (n = 23), low-activity perianal fistulas [n = 19, perianal disease activity index (PDAI) ≤ 4], high-activity perianal fistulas (n = 25, PDAI > 4) based on the PDAI. All patients underwent assessments including EUS + SWE, pelvic magnetic resonance [pelvic magnetic resonance imaging (MRI)], C-reactive protein, fecal calprotectin, CD activity index, PDAI.

RESULTS

The percentage of fistulas indicated by pelvic MRI and EUS was consistent at 82%, and there was good consistency in the classification of perianal fistulas (Kappa = 0.752, P < 0.001). Significant differences were observed in the blood flow Limberg score (χ 2 = 8.903, P < 0.05) and shear wave velocity (t = 2.467, P < 0.05) between group 2 and 3. Shear wave velocity showed a strong negative correlation with magnetic resonance novel index for fistula imaging in CD (Magnifi-CD) score (r = -0.676, P < 0.001), a weak negative correlation with the PDAI score (r = -0.386, P < 0.05), and a weak correlation between the Limberg score and the PDAI score (r = 0.368, P < 0.05).

CONCLUSION

EUS combined with SWE offers a superior method for detecting and quantitating the activity of perianal fistulas in CD patients. It may be the ideal tool to assess PFCD activity objectively for management strategies.

Different imaging techniques' diagnostic efficacy for Crohn's disease activity and external validation and comparison of MDCTAs, SES-CD and IBUSSAS

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory disease of the digestive tract with unknown etiology. It follows a relapse-remission pattern, making disease activity assessment crucial for treatment. Our study aims to evaluate the diagnostic accuracy of various imaging modalities and to validate and compare the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS), the multidetector computed tomography enterography score (MDCTEs), and the simplified endoscopic activity score for Crohn's disease (SES-CD).

METHODS

We assessed diagnostic performance using the CD Activity Index (CDAI). We first categorized patients into remission and active groups. For those in the active stage, we further categorized them into mild/moderate and severe activity groups. We used Spearman rank correlation to evaluate the relationships among IBUS-SAS, bowel wall thickness (BWT), Color Doppler imaging signal (CDS), inflammatory fat (i-fat), bowel wall stratification (BWS), and clinical inflammatory indicators.

RESULTS

A total of 103 CD patients were evaluated. The IBUS-SAS cut-off for remission and activity was 23.8, with an AUC of 0.923, sensitivity of 91.4%, and specificity of 84.8%. The SES-CD had an AUC of 0.801, sensitivity of 62.9%, and specificity of 84.4% at a cut-off of 4.5. The MDCTEs showed an AUC of 0.855, sensitivity of 77.1%, and specificity of 75.8% for a cut-off of 6.5. The Delong test revealed significant differences in diagnostic efficacy when comparing IBUS-SAS to SES-CD and IBUS-SAS to MDCTEs. In the group of mild or moderate-to-severe active, the IBUS-SAS had an AUC of 0.925, sensitivity of 83.7%, and specificity of 88.9% at a cut-off of 40. The SES-CD exhibited an AUC of 0.850, sensitivity of 90.7%, and specificity of 70.4% at a cut-off of 8.5. MDCTEs showed an AUC of 0.909, sensitivity of 83.7%, and specificity of 85.2% at a cut-off of 8.5. During Delong test, the IBUS-SAS, MDCTEs, and SES-CD showed no significant differences in assessing moderate-to-severe activity. Both IBUS-SAS and ultrasound parameters correlated with certain serum indicators (p < 0.05), although only weakly to moderately (all r < 0.5).

CONCLUSION

The IBUS-SAS, MDCTEs and SES-CD can evaluate disease remission/active and mild/moderate-to-severe active in CD, and IBUS-SAS offers the potential to precisely define CD activity.

Early Intestinal Ultrasound Response to Biologic Therapy Predicts Endoscopic Remission in Children with Ileal Crohn's Disease: Results from the Prospective Super Sonic Study

BACKGROUND AND AIMS

STRIDE-II recommends early biomarker targets for treatment optimization to achieve treat-to-target [T2T] endoscopic remission [ER] in Crohn's disease [CD]. The predictive capabilities of intestinal ultrasound [IUS] for T2T ER remain unknown. We aimed to evaluate IUS response to predict ER in children with CD.

METHODS

This was a prospective longitudinal cohort study of children with ileal [TI] CD initiating biologic therapy undergoing IUS, clinical disease activity, and C-reactive protein [CRP] assessments at baseline, week 8, 6 months, and T2T within 1 year. The primary outcome was the accuracy of optimal cut-points to predict TI ER [SES-CD ≤ 2] for change in bowel wall thickness [BWT] on IUS from baseline to week 8, and BWT at week 8. Area under the receiver operating curve [AUROC] analysis was performed and univariate analysis tested associations.

RESULTS

In total, 44 children (median age 13 [IQR 12-17] years, 29 [66%] biologic naïve) were included, and 29 [66%] achieved ER. A ≥18% decrease in TI BWT at week 8 predicted ER with an AUROC of 0.99 [95% CI 0.98-1.00], 100% sensitivity, 93% specificity, 97% positive predictive value, and 100% negative predictive value, superior to a ≥46% decrease in PCDAI (AUROC 0.67 [95% CI 0.49-0.84]) and ≥84% decrease in CRP (AUROC 0.49 [95% CI 0.31-0.67]) at week 8.

CONCLUSIONS

Early change in TI BWT on IUS is highly predictive of ER in children with CD and superior to symptoms and CRP. Our findings suggest that IUS could be used for treatment optimization and tight control to guide T2T strategies.

Non-invasive evaluation of mucosal healing by intestinal ultrasound or fecal calprotectin is efficient in Crohn's disease: A cross-sectional study

INTRODUCTION

Endoscopy is still the gold, standard for assessing disease activity in Crohn's disease (CD). Its invasiveness, poor acceptability, and cost limit its use in the era of tight control and treat-to-target management. Fecal calprotectin (FC) and intestinal ultrasound (IUS) are non-invasive alternatives to colonoscopy to assess disease activity. We aimed to evaluate the performance of IUS and FC to assess mucosal healing in CD.

METHODS

All consecutive CD patients who underwent colonoscopy for mucosal healing assessment and IUS and/or FC within four weeks between September 2019 and April 2022 were included in a prospective cohort. The bowel-wall thickness (BWT) and color Doppler signal (CDS) were assessed for each segment. Endoscopic remission was defined by a CDEIS score < 3.

RESULTS

In total, 153 patients were included, of whom 122 showed endoscopic mucosal healing. Eighty-two (53.6 %) were female, the median was age 36 years (IQR, 28-46), and the median disease duration was 10 years (IQR, 4-19). The sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) of a BWT < 3 mm to predict endoscopic mucosal healing were 56 %, 88 %, 95 %, and 36 %, respectively (patients misclassified as mucosal healing, 2.5 %). The best FC threshold (< 92.9 µg/g) provided similar results: 77 %, 89 %, 96 %, and 67 %, respectively (patients misclassified, 2.2 %). The association of an FC < 250 µg/g with a BWT < 3 mm and the absence of CDS increased the Sp and PPV: Se 58 %, Sp 95 %, PPV 97 %, VPN 43 %; patients misclassified, 1.3 %.

CONCLUSION

Noninvasive evaluation of mucosal healing by IUS or calprotectin efficiently identifies patients with CD who have achieved endoscopic mucosal healing.

Role of Intestinal Ultrasound for IBD Care: A Practical Approach

Intestinal ultrasound (IUS) has recently become the imaging technique of choice for patients with different types of intestinal inflammation. IUS has a high sensitivity, specificity, positive predictive value, and negative predictive value when diagnosing Crohn's disease or ulcerative colitis. Further, it is now the preferred imaging modality for routine IBD reevaluations because of its non-invasiveness, cost-effectiveness, availability (at least in Europe), and reproducibility in all age groups. However, the clinical success of IUS requires IUS training for doctors and technicians who perform IUS with a standardised description of ultrasound findings of the terminal ileum and entire colon. Complications such as abscess formation, fistulae, and stenosis can be detected by either conventional IUS or contrast-enhanced ultrasound (CEUS). Lately, several disease activity scores have been proposed for Crohn's disease, postoperative Crohn's disease, and ulcerative colitis both in adults (including elderly) and in children. IUS was successfully used in randomised clinical trials in order to measure the treatment response. Therefore, IUS now plays a central role in clinical decision making.

Intestinal Ultrasound, Fecal Calprotectin, and Their Combination to Predict Endoscopic Mucosal Healing in Ulcerative Colitis: A Real-Life Cross-Sectional Study

BACKGROUND

The development of noninvasive markers to assess mucosal healing in ulcerative colitis (UC) is essential in the treat-to-target era. The aim of this study was to evaluate the performance of intestinal ultrasound (IUS), fecal calprotectin (FC), and their combination to assess mucosal healing in UC patients.

METHODS

All consecutive patients between January 2021 and September 2022 with UC who underwent a complete colonoscopy and IUS and/or an FC test within 4 weeks were included in a prospective cohort. Bowel wall thickness (BWT) and the color Doppler signal (CDS) were assessed for each segment. Endoscopic mucosal healing was defined by a Mayo score of 0 to 1.

RESULTS

A total of 61 patients were included, of whom 79% showed endoscopic healing (26 Mayo 0 and 11 Mayo 1). Among the patients, 16 (27.6%) of 58 had a BWT <3 mm, and 41 (70.7%) of 58 had no CDS. The sensitivity, specificity, positive predictive value, and negative predictive value of a BWT <3 mm to predict endoscopic mucosal healing were 37%, 77%, 72%, and 44%, respectively. The association of FC <150 µg/g, a BWT <3 mm, and a CDS = 0 increased the specificity and positive predictive value (sensitivity 33%, specificity 94%, positive predictive value 89%, negative predictive value 48%). The combination of a normal IUS, no rectal bleeding, and an FC <172 µg/g identified all patients with mucosal healing.

CONCLUSION

The combination of IUS and FC is effective in identifying mucosal healing in UC. Noninvasive evaluation of mucosal healing is possible for most UC patients.

Leveraging existing mid-end ultrasound machine for point-of-care intestinal ultrasound in low-resource settings: Prospective, real-world impact on clinical decision-making

BACKGROUND

Point-of-care ultrasound (POCUS) has transformed inflammatory bowel disease (IBD) management, but the cost to purchase high-end equipment can be prohibitive.

AIM

To assess prospectively the feasibility of POCUS using pre-existing mid-end ultrasound equipment without incurring additional cost.

METHODS

Consecutive IBD patients underwent POCUS with or without faecal calprotectin (FCP) using a mid-end ultrasound machine. If POCUS with or without FCP could not guide management, we performed additional ileocolonoscopy or cross-sectional imaging. We evaluated the impact of POCUS on IBD management and its correlation with ileocolonoscopy or cross-sectional imaging. We analysed pregnant, paediatric and post-operative patients separately.

RESULTS

Among 508 patients with IBD, we analysed 419 (60.4% Crohn's disease [CD]; 61.3% male, age [years]: 36 [18-78]) undergoing 556 POCUS sessions. POCUS with or without FCP independently influenced clinical management in 42.8% of patients with CD and 49.7% with ulcerative colitis (UC). POCUS helped avoid colonoscopy in 51.4% of patients with CD and 51.8% with UC, and cross-sectional imaging in 38.1% of suspected active small bowel CD. In patients with additional diagnostics, POCUS-based decisions remained unchanged in 81.2% with CD and 85% with UC. Sensitivity and specificity of POCUS compared to ileocolonoscopy were 80% and 94.4% for CD and 80.8% and 92.8% for UC, respectively. Sensitivity and specificity compared to cross-sectional imaging were 87.2% and 87.5%, respectively.

CONCLUSION

POCUS using existing mid-end ultrasound equipment in low-resource settings influenced IBD clinical decision-making with excellent accuracy, often avoiding colonoscopy and cross-sectional imaging.

Multimodal dynamic ultrasound approach as predictor of response in patients with Crohn's disease treated with ustekinumab

Background

The approval of ustekinumab (UST) has opened new options for the treatment of Crohn's disease (CD), but potential markers predicting the efficacy of this interleukin-12/23 inhibitor are lacking. Contrast-enhanced ultrasound (CEUS) is non-invasive alternative to endoscopy, demonstrating early transmural changes after treatment induction.

Objectives

We conducted a prospective monocentric study aiming to explore the value of multimodal intestinal ultrasound (IUS) in predicting the response to UST in patients with active CD who have been previously exposed to anti-tumour necrosis factor α (TNFα).

Design and methods

Consecutive patients with moderate-to-severe CD involving the terminal ileum who were scheduled to begin UST therapy were enrolled between January 2020 and October 2021 in the inflammatory bowel diseases outpatient centre. A complete IUS evaluation, including B-mode, Doppler, dynamic CEUS and elastography, was performed at the time of induction (T0) and after 8 (T1), 16 (T2), 24 (T3) and 48 (T4) weeks of therapy. Each IUS parameter and their variations from baseline were correlated with endoscopic response and mucosal healing after 1 year.

Results

A total of 52 patients were included, 29 (55.8%) of which reached endoscopic response at T4. The univariate analysis revealed that, between T3 and T0, the percentage changes of bowel wall thickness, Limberg score, mean signal intensity, rise time, wash-in rate, C reactive protein and Harvey-Bradshaw Index were associated with long-term therapeutic outcome. Based on the above parameters, we developed an IUS score that showed a good performance in predicting 1 year-endoscopic response (area under the curve: 0.91).

Conclusion

Multimodal ultrasound could be helpful to predict long-term therapeutic outcome in patients with CD treated with UST.

Registration

NCT05987501.

Challenges in IBD Research 2024: Novel Technologies

Novel technology is one of the five focus areas of the Challenges in Inflammatory Bowel Disease (IBD) Research 2024 document. Building off the Challenges in IBD Research 2019 document, the Foundation aims to provide a comprehensive overview of current gaps in IBD research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in interception, remission, and restoration for these diseases. The document is the result of a multidisciplinary collaboration from scientists, clinicians, patients, and funders and represents a valuable resource for patient-centric research prioritization. Specifically, the Novel Technologies section focuses on addressing key research gaps to enable interception and improve remission rates in IBD. This includes testing predictions of disease onset and progression, developing novel technologies tailored to specific phenotypes, and facilitating collaborative translation of science into diagnostics, devices, and therapeutics. Proposed priority actions outlined in the document include real-time measurement of biological changes preceding disease onset, more effective quantification of fibrosis, exploration of technologies for local treatment of fistulas, and the development of drug delivery platforms for precise, location-restricted therapies. Additionally, there is a strong emphasis on fostering collaboration between various stakeholders to accelerate progress in IBD research and treatment. Addressing these research gaps necessitates the exploration and implementation of bio-engineered novel technologies spanning a spectrum from materials to systems. By harnessing innovative ideas and technologies, there's a collective effort to enhance patient care and outcomes for individuals affected by IBD.

Biomarkers in inflammatory bowel disease: a practical guide

Inflammatory bowel disease (IBD), comprising ulcerative colitis (UC) and Crohn's disease (CD), is a costly condition in terms of morbidity and healthcare utilization, with an increasing prevalence now approaching 1% in the Western world. Endoscopic assessment of IBD remains the gold standard for diagnosis, evaluation of treatment response and determination of post-operative recurrence, but is expensive and invasive. Biomarkers can facilitate non-invasive disease assessment, with C-reactive protein and faecal calprotectin as the most widely available biomarkers in current clinical practice. This narrative review summarizes the evidence for their use in both UC and CD and offers practical guidance for healthcare providers taking into account the limitations of biomarker interpretation. We present evidence for the future use of novel biomarkers in IBD and discuss how biomarker discovery could deliver the goal of precision medicine in IBD.

Determining the Accuracy of Intestinal Ultrasound Scores as a Prescreening Tool in Crohn's Disease Clinical Trials

INTRODUCTION

High rates of screen failure for the minimum Simple Endoscopic Score for Crohn's Disease (SES-CD) plague Crohn's disease (CD) clinical trials. We aimed to determine the accuracy of segmental intestinal ultrasound (IUS) parameters and scores to detect segmental SES-CD activity.

METHODS

A single-center, blinded, cross-sectional cohort study of children and young adult patients with CD undergoing IUS and ileocolonoscopy, comparing segmental IUS bowel wall thickness (BWT), hyperemia (modified Limberg score [MLS]), and scores to detect segmental SES-CD activity: (i) SES-CD ≤2, (ii) SES-CD ≥6, and (iii) SES-CD ≥4 in the terminal ileum (TI) only. Primary outcome was accuracy of BWT, MLS, and IUS scores to detect SES-CD ≤2 and SES-CD ≥6. Secondary outcomes were accuracy of TI BWT, MLS, and IUS scores to detect SES-CD ≥4 and correlation with the SES-CD.

RESULTS

Eighty-two patients (median [interquartile range] age 16.5 [12.9-20.0] years) underwent IUS and ileocolonoscopy of 323 bowel segments. Segmental BWT ≤3.1 mm had a similar high accuracy to detect SES-CD ≤2 as IUS scores (area under the receiver operating curve [AUROC] 0.833 [95% confidence interval 0.76-0.91], 94% sensitivity, and 73% specificity). Segmental BWT ≥3.6 mm and ≥4.3 mm had similar high accuracy to detect SES-CD ≥6 (AUROC 0.950 [95% confidence interval 0.92-0.98], 89% sensitivity, 93% specificity) in the colon and an SES-CD ≥4 in the TI (AUROC 0.874 [0.79-0.96], 80% sensitivity, and 91% specificity) as IUS scores. Segmental IUS scores strongly correlated with the SES-CD.

DISCUSSION

Segmental IUS BWT is highly accurate to detect moderate-to-severe endoscopic inflammation. IUS may be the ideal prescreening tool to reduce unnecessary trial screen failures.

Inflammatory mesenteric fat detected by Intestinal ultrasound is correlated with poor long-term clinical outcomes in patients with Crohn's disease

BACKGROUND

Data on the correlation between inflammatory mesenteric fat (i-fat), detected by intestinal ultrasound (IUS), and the prognosis of Crohn's disease (CD) remains limited.

AIMS

To investigate the impact of IUS-detected i-fat on long-term clinical outcomes.

METHODS

We retrospectively enrolled 171 active CD patients who initiated infliximab. Clinical remission (CR), mucosal healing (MH) and transmural healing (TH) were assessed at week-14 and 1 year.

RESULTS

Baseline i-fat was detected in 107 patients, while 64 without i-fat. At week-14 and 1 year, patients with i-fat showed lower rates of CR (61.7% vs. 87.5%; 62.3% vs. 86.7%), MH (20.6% vs. 46.9%; 38.6% vs. 65.0%) and TH (10.3% vs. 31.3%; 21.6% vs. 51.7%), compared to those without (all p<0.01). Multivariable analysis revealed that baseline i-fat was a negative predictor for CR (OR=0.212) and MH (OR=0.425) at week-14, and CR (OR=0.340) and TH (OR=0.364) at 1 year (all p<0.05). At week-14, 56 patients with baseline i-fat recovered to without i-fat. Patients with i-fat recovery had higher rates of CR (86.8% vs. 23.1%), MH (58.5% vs. 7.7%) and TH (34.0% vs. 2.6%) at 1 year than those with i-fat at week-14 (all p<0.001).

CONCLUSION

IUS-detected i-fat correlated poor long-term clinical outcomes in CD with infliximab.

Current Developments and Role of Intestinal Ultrasound including the Advent of AI

Intestinal ultrasound is a non-invasive, safe, and cost-effective technique to study the small and large intestines. In addition to conventional B-mode and color doppler imaging, new US tools have been developed in more recent years that provide auxiliary data on many GI conditions, improving the diagnosis and assessment of relevant outcomes. We have reviewed the more recent literature (from 2010 onwards) on auxiliary tools in bowel ultrasound such as elastography techniques, CEUS, SICUS, and the potential contribution by artificial intelligence (AI) to overcome current intestinal ultrasound limitations. For this scoping review, we performed an extensive literature search on PubMed and EMBASE to identify studies published until December 2023 and investigating the application of elastography techniques, CEUS, SICUS, and AI in the ultrasonographic assessment of the small and large intestines. Multiparametric intestinal ultrasound shows promising capabilities in Crohn's disease, while less is known about the role in ulcerative colitis. Despite some evidence, the CEUS role as a point-of-care examination tool for rare conditions such as intestinal GvHD and ischemic small bowel disease seems promising, possibly avoiding the need to perform further cross-sectional imaging. The use of AI in intestinal ultrasound is still anecdotical and limited to acute appendicitis.

Radiomics-Based Analysis of Intestinal Ultrasound Images for Inflammatory Bowel Disease: A Feasibility Study

Background

The increasing adoption of intestinal ultrasound (IUS) for monitoring inflammatory bowel diseases (IBD) by IBD providers has uncovered new challenges regarding standardized image interpretation and limitations as a research tool. Artificial intelligence approaches can help address these challenges. We aim to determine the feasibility of radiomic analysis of IUS images and to determine if a radiomics-based classification model can accurately differentiate between normal and abnormal IUS images. We will also compare the radiomic-based model's performance to a convolutional neural network (CNN)-based classification model to understand which method is more effective for extracting meaningful information from IUS images.

Methods

Retrospectively analyzing IUS images obtained during routine outpatient visits, we developed and tested radiomic-based and CNN-based models to distinguish between normal and abnormal images, with abnormal images defined as bowel wall thickness > 3 mm or bowel hyperemia with modified Limberg score ≥ 1 (both are surrogate markers for inflammation). Model performances were measured by area under the receiver operator curve (AUC).

Results

For this feasibility study, 125 images (33% abnormal) were analyzed. A radiomic-based model using XG boost yielded the best classifier model with average test AUC 0.98%, 93.8% sensitivity, 93.8% specificity, and 93.7% accuracy. The CNN-based classification model yielded an average testing AUC of 0.75.

Conclusions

Radiomic analysis of IUS images is feasible, and a radiomic-based classification model could accurately differentiate abnormal from normal images. Our findings establish methods to facilitate future radiomic-based IUS studies that can help standardize image interpretation and expand IUS research capabilities.

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.

Bedside Intestinal Ultrasound Predicts Disease Severity and the Disease Distribution of Pediatric Patients With Inflammatory Bowel Disease: A Pilot Cross-sectional Study

BACKGROUND

Intestinal ultrasound (IUS) is a noninvasive tool to assess bowel inflammation. There is a paucity of data on its accuracy in pediatric patients.

AIM

The aim of this study is to evaluate the diagnostic performance of bowel wall thickness (BWT) measured using IUS compared with endoscopic disease activity in children suspected of having inflammatory bowel disease (IBD).

METHODS

We conducted a single-center cross-sectional pilot study of pediatric patients suspected to have previously undiagnosed IBD. Endoscopic inflammation was graded using segmental scores of the Simple Endoscopic Score for Crohn's Disease (SES-CD) and the Ulcerative Colitis Endoscopic Index of Severity (UCEIS) and classified as having healthy, mild, or moderate/severe disease activity. Association between BWT and endoscopic severity was assessed using the Kruskal-Wallis test. The diagnostic performance of BWT to detect active disease at endoscopy was evaluated using the area under the receiver operating characteristic curve; sensitivity and specificity were calculated.

RESULTS

In all, 174 bowel segments in 33 children were assessed by IUS and ileocolonoscopy. An elevated median BWT was associated with increased bowel segment disease severity, classified by the SES-CD (P < .001) and the UCEIS (P < .01). Using a cutoff value of 1.9 mm, we found that the BWT had an area under the receiver operating characteristic curve of 0.743 (95% CI, 0.67-0.82), a sensitivity of 64% (95% CI, 53%-73%), and a specificity of 76% (95% CI, 65%-85%) to detect inflamed bowel.

CONCLUSION

Increasing BWT is associated with increasing endoscopic activity in pediatric IBD. Our study suggests that the optimal BWT cutoff value for detecting active disease may be less than that seen in adults. Additional pediatric studies are needed.

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.

Clinical Application of Intestinal Ultrasound in Inflammatory Bowel Disease

PURPOSE OF REVIEW

Intestinal ultrasound (IUS) is a non-invasive, accurate, and well-tolerated tool that provides real-time assessment of inflammatory bowel disease (IBD) activity and is therefore an ideal monitoring tool. This review describes the evolving role of IUS in each phase of clinical management of IBD.

RECENT FINDINGS

Accumulating evidence has demonstrated that IUS is an excellent tool for the assessment of suspected IBD, with a very high negative predictive value. It accurately assesses disease activity, disease complications, and in the pre-treatment phase, provides a benchmark for subsequent follow-up. IUS can detect early therapeutic response and correlates well with other established monitoring modalities with arguably superior predictive capabilities and ability to assess a deeper degree of remission, transmural healing (TH). IUS has a crucial role in the management of IBD and has ushered in a new era of monitoring with more rapid evaluation and the opportunity for early optimization, deeper therapeutic targets, and improved outcomes.

Intestinal ultrasound in inflammatory bowel disease: New kid on the block

Intestinal ultrasound is an emerging technique for diagnosing and monitoring patients with inflammatory bowel disease (IBD). It is a simple, non-invasive, inexpensive, safe and reliable tool for monitoring patients with IBD. This technique has good diagnostic accuracy in the assessment of the extent and severity of IBD and its complications. The most commonly used parameters are bowel wall thickness, color Doppler flow, bowel wall stratification and peri-bowel inflammation. Various scoring systems have been developed utilizing the above parameters to monitor patients with IBD. It is a good tool to monitor response to therapy and follow-up for post-operative recurrence. Early response on intestinal ultrasound (IUS) predicts long-term clinical remission and mucosal healing in patients with Crohn's disease. In patients with ulcerative colitis (UC), the response to IUS can be assessed as early as two weeks. Recent data has emerged to predict the response to corticosteroids and colectomy in patients with acute severe UC. Point of care IUS in the outpatient clinic is an excellent tool to follow-up patients and guide clinical decision-making and has good acceptability among patients. It is an underutilized technique in spite of its appeal and the availability of evidence. Underutilization can be attributed to the lack of awareness, expertise and training centres. This review discusses the technical details and the evidence to support the use of IUS in IBD. We aim to increase awareness and use of intestinal ultrasound and build local expertise and data.

Ultrasound in Pediatric Inflammatory Bowel Disease-A Review of the State of the Art and Future Perspectives

Inflammatory bowel disease (IBD) comprises a group of relapsing, chronic diseases of the gastrointestinal tract that, in addition to adults, can affect children and adolescents. To detect relapses of inflammation, these patients require close observation, frequent follow-up, and therapeutic adjustments. While reference standard diagnostics include anamnestic factors, laboratory and stool sample assessment, performing specific imaging in children and adolescents is much more challenging than in adults. Endoscopic and classic cross-sectional imaging modalities may be invasive and often require sedation for younger patients. For this reason, intestinal ultrasound (IUS) is becoming increasingly important for the non-invasive assessment of the intestine and its inflammatory affection. In this review, we would like to shed light on the current state of the art and provide an outlook on developments in this field that could potentially spare these patients more invasive follow-up procedures.

Intestinal ultrasound score predicts therapeutic outcomes of infliximab in pediatric patients with Crohn's disease

BACKGROUND AND AIMS

Objective evaluation of treatment response is critical in the management of Crohn's disease (CD). Compared with endoscopy, intestinal ultrasound (IUS) is non-invasive and well-tolerated. This study is aimed to assess the predictive value of IUS score for treatment response in pediatric CD patients.

METHODS

We conducted a retrospective study in pediatric CD patients who underwent endoscopy and IUS at start of infliximab treatment [T0] and after 22-38 weeks [T1] between February 2021 and January 2023. Pediatric Crohn's Disease Activity Index (PCDAI), biochemical parameters, the Simple Endoscopic Score for Crohn's disease (SES-CD) and IUS parameters were collected at two timepoints. IUS scores were assessed by International Bowel Ultrasound Segment Activity Score (IBUS-SAS).

RESULTS

Thirty patients were included, with 53.3% reaching endoscopic response and 43.3% endoscopic remission. After infliximab treatment, IBUS-SAS (58.5 ± 24.2 vs 34.4 ± 21.6, p = .0001) was significantly decreased. At T1, change in IBUS-SAS (-38.2 ± 22.0 vs -7.9 ± 24.1, p = .0015) were pronounced in patients with endoscopic response compared with endoscopic non-response. Significant correlation were observed between IBUS-SAS and SES-CD, PCDAI, C-reaction protein, erythrocyte sedimentation rate, hemoglobin, albumin. The most accurate cutoff values for predicting endoscopic response were 57.4% decrease of IBUS-SAS (AUROC: 0.862, p < .001). The optimal cut-off of IBUS-SAS to correlate endoscopic remission was 26.0 (AUROC: 0.686, p = .017).

CONCLUSIONS

The validated ultrasound-base score, IBUS-SAS is an effective index for monitoring endoscopic response to infliximab therapy in CD. IUS evaluation could guide treatment decision for pediatric CD.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL RELEVANCE STATEMENT

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

KEY POINTS

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

Effectiveness of Partial Enteral Nutrition as Add-On to Biologics in Patients With Refractory and Difficult-to-Treat Crohn's Disease: A Pilot Study

Background

Partial enteral nutrition (PEN) is a well-established treatment for children with Crohn's disease (CD). However, its efficacy in adults with CD remains uncertain. We aimed to assess the effectiveness of PEN as an add-on to escalated biological therapy in adults with CD who have lost response to biologics.

Methods

We conducted a retrospective observational study including patients who had lost response to biologics and received PEN in combination with escalated treatment, compared to those treated only with escalated therapy. The primary endpoint was steroid-free clinical remission (CR) at 24 weeks. Secondary endpoints included transmural healing (TH) and response (TR) rates along with selected clinical outcomes.

Results

Forty-two patients were screened; 12 (28.6%) were excluded for complicated disease and 30 (71.4%) were included in the final analysis. Fourteen (46.7%) patients completed PEN treatment at 8 weeks, while 16 patients (53.3%) discontinued treatment due to intolerance and continued with escalation of biologic (BT group). At 24 weeks, 9 patients (64.3%) in the PEN group achieved CR, compared to 4 patients (25%) in the BT group (P = .03). The TR rate was 64.9% in the PEN group and 25% in the BT group (P = .03). Patients receiving PEN exhibited an increase in albumin levels compared to those in the BT group (Δ = 0.5; P = .02). A higher rate of therapy changes (68.7%) was observed in the BT group compared to 14.2% in the PEN group (P = .004). Prior failure to 2 lines of biological therapy was associated with adherence to PEN (OR = 1.583; CI = 1.06-2.36; P = .01).

Conclusions

In patients who had lost response to biologics, PEN in combination with escalated biologics was associated with CR and TR and improved nutritional status. Hence, the addition of PEN should be considered for patients with difficult-to-treat CD.