Accuracy of Ultrasound for Evaluation of Colorectal Segments in Patients With Inflammatory Bowel Diseases: A Systematic Review and Meta-analysis

Intestinal Ultrasound in Common Gastrointestinal Disorders: An Evidence-Based Approach

Patients with abdominal symptoms are among the most common to present both urgently and non-urgently for medical evaluation. While intestinal ultrasound (IUS) is useful to aid management of these patients, it is not routinely taught, performed, or included as part of the core set of point-of-care ultrasound competencies. The authors present an approach to performing a systematic, but focused, IUS at the bedside and diagnostic accuracies for small bowel obstruction inflammatory bowel disease, appendicitis, and diverticulitis. An approach on how to integrate IUS findings and common pitfalls will also be discussed.

Using Participatory Narrative Inquiry to Assess Experiences and Self-Experimentation with Diet Interventions in Inflammatory Bowel Disease Patients

BACKGROUND AND AIMS

To improve quality of life (QoL), patients with inflammatory bowel diseases (Crohn's disease and ulcerative colitis) often self-experiment with lifestyle changes such as dietary modifications. The nature (e.g., type of interventions, expectations, perceived efficacy) of these single-subject experiments has not been systematically investigated.

METHOD

We used Participatory Narrative Inquiry (PNI), a structured qualitative method, to obtain information about these experiments through patient stories.

RESULTS

We demonstrate that PNI can be a method to collect and analyze IBD patient ideas and experiences regarding lifestyle and nutritional factors in a structured manner to reveal valuable insights for personal and scientific follow-up research. Patients report rest, (psychological) balance, and a change in diet when describing times when they experienced a better QoL. When focusing on diet, patients reported a considerable number of food products that were experienced as beneficial by one person but detrimental by another.

CONCLUSIONS

PNI is a suitable method to obtain information about self-experimentation. An insight that was attained was that personalized (dietary) guidance that supports the individual is needed.

Imaging in Inflammatory Bowel Disease

The incidence of inflammatory bowel disease (IBD) is rising globally. We need more tools and techniques in our armamentarium for early diagnosis, tight monitoring, and to assess disease complications of IBD. This article reviews the role of cross-sectional imaging, mainly computed tomography, MRI, and intestinal ultrasound (IUS) in IBD and its advantages, disadvantages, and limitations. While popular in other parts of the world, IUS is underutilized in the United States. It is safe, accurate, can be repeated multiple times and provides quick and actionable results in IBD care without the risk of radiation and contrast.

Differentiation of Active Ulcerative Colitis vs Noninflammatory Bowel Disease Proctitis by Transperineal Superb Microvascular Imaging

BACKGROUND

Transabdominal ultrasonography and transperineal ultrasonography (TPUS) appear correspond to colonoscopy (CS) for evaluating ulcerative colitis (UC) activity, but their utility in UC diagnosis remains unclear. This research compared the accuracy of TPUS and CS for assessing rectal activity and differentiating noninflammatory bowel disease proctitis from UC in pediatric cases.

METHODS

The study is a blinded, prospective, and controlled trial. Prospectively, values of fecal calprotectin (FCP) and findings of the TPUS and CS were compared between child cases of UC and non-IBD proctitis. Findings of rectal wall thickening (RWT), rectal wall flow (RWF) on power Doppler, and microvascular signal at wall circumference (MSWC) on monochrome superb microvascular imaging assessed using TPUS were compared with the CS.

RESULTS

Thirty patients with Mayo endoscopic subscore (MES) 0 to 1 UC, 57 with MES 2 to 3 UC, and 44 with proctitis were registered. Fecal calprotectin, RWF, and MSWC indicated significant differences among the groups (P < .05). Rectal wall thickening showed no significant difference between MES 0-1 and proctitis (P = .76). Rectal wall thickening and MSWC were independent predictors of endoscopic activity of UC, resulting in a sensitivity and specificity of 100% for RWT ≥4.5 mm and positive MSWC. Fecal calprotectin and RWF were independent predictors for differentiating MES 0 to 1 and proctitis, and FCP and RWT were independent predictors for differentiating MES 2 to 3 and proctitis. Sensitivity and specificity were 77.2% and 80.9%, respectively, for FCP >242.5 μg/g and RWF negative; and they were both 100% for RWT >4.1 mm and MSWC positive.

CONCLUSIONS

Transperineal ultrasonography with mSMI may enable the evaluation of rectal activity and differentiation of UC from non-IBD proctitis with accuracy comparable to endoscopy.

Management of ulcerative colitis in Taiwan: consensus guideline of the Taiwan Society of Inflammatory Bowel Disease updated in 2023

Ulcerative colitis (UC) is a chronic inflammation of the gastrointestinal tract and is characterized by alternating periods of inflammation and remission. Although UC incidence is lower in Taiwan than in Western countries, its impact remains considerable, demanding updated guidelines for addressing local healthcare challenges and patient needs. The revised guidelines employ international standards and recent research, emphasizing practical implementation within the Taiwanese healthcare system. Since the inception of the guidelines in 2017, the Taiwan Society of Inflammatory Bowel Disease has acknowledged the need for ongoing revisions to incorporate emerging therapeutic options and evolving disease management practices. This updated guideline aims to align UC management with local contexts, ensuring comprehensive and context-specific recommendations, thereby raising the standard of care for UC patients in Taiwan. By adapting and optimizing international protocols for local relevance, these efforts seek to enhance health outcomes for patients with UC.

Intestinal ultrasound for intestinal Behçet disease reflects endoscopic activity and histopathological findings

BACKGROUND/AIMS

Intestinal Behçet disease is typically associated with ileocecal punched-out ulcers and significant morbidity and mortality. Intestinal ultrasound is a noninvasive imaging technique for disease monitoring. However, no previous reports have compared intestinal ultrasound with endoscopic ulcer activity or histopathological findings for intestinal Behçet disease. We evaluated the usefulness of intestinal ultrasound for assessing the activity of ileocecal ulcers in intestinal Behçet disease.

METHODS

We retrospectively compared intestinal ultrasound findings with 73 corresponding endoscopic images and 6 resected specimens. The intestinal ultrasound findings were assessed for 7 parameters (bowel wall thickness, vascularity [evaluated using the modified Limberg score with color Doppler], bowel wall stratification, white-plaque sign [strong hyperechogenic lines or spots], mesenteric lymphadenopathy, extramural phlegmons, and fistulas), and endoscopic ulcer activity was classified into active, healing, and scar stages. Histopathological findings were evaluated by consensus among experienced pathologists.

RESULTS

Bowel wall thickness (P< 0.001), vascularity (P< 0.001), loss of bowel wall stratification (P= 0.015), and white-plague sign (P= 0.013) were significantly exacerbated in the endoscopic active ulcer stage. Receiver operating characteristic curve analysis revealed that a bowel wall thickness of > 5.5 mm (sensitivity 89.7%, specificity 85.3%) was potentially useful for detecting active lesions. When compared with histopathological findings, an increase in bowel wall thickness reflected the ulcer marginal ridge, and the white-plaque sign reflected the ulcer bottom.

CONCLUSIONS

Intestinal ultrasound is useful for monitoring intestinal ulcer activity in intestinal Behçet disease.

How close are we to a success stratification tool for improving biological therapy in ulcerative colitis?

INTRODUCTION

Biological therapies have become the standard treatment for ulcerative colitis (UC). However, clinical remission rates post-induction therapy remain modest at 40-50%, with many initial responders losing response over time. Current treatment strategies frequently rely on a 'trial and error' approach, leading to prolonged periods of ineffective and costly therapies for patients, accompanied by associated treatment complications.

AREA COVERED

This review discusses current evidence on risk stratification tools for predicting therapeutic efficacy and minimizing adverse events in UC management. Recent studies have identified predictive factors for biologic therapy response. In the context of personalized medicine, the goal is to identify patients at high risk of progression and complications, as well as those likely to respond to specific therapies. Essential risk stratification tools include clinical decision-making aids, biomarkers, genomics, multi-omics factors, endoscopic, imaging, and histological assessments.

EXPERT OPINION

Employing risk stratification tools to predict therapeutic response and prevent treatment-related complications is essential for precision medicine in the biological management of UC. These tools are necessary to select the most suitable treatment for each individual patient, thereby enhancing efficacy and safety.

The Diagnostic Utility of Biochemical Markers and Intestinal Ultrasound Compared with Endoscopy in Patients with Crohn's Disease and Ulcerative Colitis: A Systemic Review and Meta-Analysis

Background: Inflammatory bowel disease (IBD) consists of Crohn's disease (CD) and Ulcerative colitis (UC). The main goal of treatment is to obtain mucosal healing via endoscopy. More recently, intestinal ultrasounds, along with biochemical markers, have been increasingly popular as point-of-care testing to monitor treatment response. This systemic review and meta-analysis aimed to assess the diagnostic test performance of ultrasonography and biochemical markers (C-reactive protein and fecal calprotectin) compared with endoscopy for detecting inflammation in IBD. Methods: A comprehensive literature search was conducted using PubMed Medline, EMBASE, ScienceDirect, and CINAHL from 1 January 2018 to 1 January 2024. The included studies were prospective and retrospective observational studies, clinical trials, and cross-sectional studies investigating the diagnostic sensitivity and specificity of ultrasonography, biochemical markers, and endoscopy. Studies were selected based on the Preferred Reporting Items for Systematic Review and Meta-analysis Statement (PRISMA). Results: Of the 1035 studies retrieved, 16 met the inclusion criteria, and most of the included studies were prospective observational studies. Diagnostic test accuracy was conducted, and the pooled sensitivity and specificity of all the studies revealed that ultrasonography has the highest pooled sensitivity, at 85% (95% CI, 78 to 91%), and specificity, at 92% (95% CI, 86 to 96%), as compared with biochemical markers and endoscopy. More specifically, biochemical markers had a pooled sensitivity and specificity of 85% (95% CI, 81 to 87%) and 61% (95% CI, 58 to 64%), respectively, and endoscopy had 60% (95% CI, 52 to 68%) and 82% (95% CI, 76 to 87%), respectively. However, the results also show substantial heterogeneity in the studies because of various populations, protocols, and outcomes in the studies included. This was especially noted in the assessment of biochemical markers, in which a metaregression was performed showing a nonsignificant p-value of 0.8856 for the coefficient. Conclusions: IUS was found to have the highest pooled sensitivity and specificity of all the included studies for diagnosing inflammation in patients with CD and UC, and this, coupled with biochemical markers, can improve diagnostic utility.

Early Sonographic Improvement Predicts Clinical Remission and Mucosal Healing With Molecular-Targeted Drugs in Ulcerative Colitis

Background and Aims

Predicting the efficacy of molecular-targeted drugs (MTDs) is an unmet need in the treatment of ulcerative colitis (UC). Intestinal ultrasound (IUS) can be used to safely and repeatedly assess UC activity.

Methods

Thirty-eight patients who started MTD therapy for active UC and underwent IUS at baseline and 3 months after starting therapy were analyzed. Steroid-free clinical remission (SFCR) and endoscopic improvement (EI) at 6 months were defined as a Lichtiger index of ≤3 and Mayo endoscopic subscore of ≤1 while continuing the MTD without steroid induction or surgery. Sonographically estimated EI (SE-EI) at 3 months was assessed based on a Milan Ultrasound Criterion of ≤6.2 and Kyorin Ultrasound Criterion for UC (bowel wall thickness of <3.8 mm and submucosa index of <50%).

Results

Thirty-one patients achieved SFCR at 6 months [SFCR(+) group]. The SFCR(+) group demonstrated significantly better improvement in bowel wall thickness and bowel wall vascularity at 3 months than the SFCR(-) group. The Milan Ultrasound Criterion and UC-IUS index also improved significantly more in the SFCR(+) than SFCR(-) group. The areas under the curve of these parameters for predicting SFCR were approximately 0.80. Colonoscopy was performed for 28 patients at 6 months, and 15 patients achieved EI. SE-EI at 3 months was significantly associated with achievement of EI at 6 months. The positive predictive values of SE-EI at 3 months for SFCR and EI at 6 months were 100%.

Conclusion

Sonographic improvements in 3 months predicted the clinical and endoscopic efficacy of MTD therapy at 6 months, suggesting the longitudinal significance of IUS monitoring for UC treatment.

Inflammatory Bowel Diseases and Non-Alcoholic Fatty Liver Disease: Piecing a Complex Puzzle Together

Inflammatory bowel diseases (IBD), comprising Crohn's disease and ulcerative colitis, are systemic and multifaceted disorders which affect other organs in addition to the gastrointestinal tract in up to 50% of cases. Extraintestinal manifestations may present before or after IBD diagnosis and negatively impact the intestinal disease course and patients' quality of life, often requiring additional diagnostic evaluations or specific treatments. Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. Current evidence shows an increased prevalence of NAFLD (and its more advanced stages, such as liver fibrosis and steatohepatitis) in IBD patients compared to the general population. Many different IBD-specific etiopathogenetic mechanisms have been hypothesized, including chronic inflammation, malabsorption, previous surgical interventions, changes in fecal microbiota, and drugs. However, the pathophysiological link between these two diseases is still poorly understood. In this review, we aim to provide a comprehensive overview of the potential mechanisms which have been investigated so far and highlight open issues still to be addressed for future studies.

High-throughput omics technologies in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, relapsing intestinal disease. Elucidation of the pathogenic mechanisms of IBD requires high-throughput technologies (HTTs) to effectively obtain and analyze large amounts of data. Recently, HTTs have been widely used in IBD, including genomics, transcriptomics, proteomics, microbiomics, metabolomics and single-cell sequencing. When combined with endoscopy, the application of these technologies can provide an in-depth understanding on the alterations of intestinal microbe diversity and abundance, the abnormalities of signaling pathway-mediated immune responses and functionality, and the evaluation of therapeutic effects, improving the accuracy of early diagnosis and treatment of IBD. This review comprehensively summarizes the development and advancement of HTTs, and also highlights the challenges and future directions of these technologies in IBD research. Although HTTs have made striking breakthrough in IBD, more standardized methods and large-scale dataset processing are still needed to achieve the goal of personalized medicine.

A combination of bowel wall thickness and submucosa index is useful for estimating endoscopic improvement in ulcerative colitis: external validation of the Kyorin Ultrasound Criterion

BACKGROUND

Endoscopic improvement (EI; a Mayo endoscopic subscore of 0 or 1) is considered a therapeutic target in ulcerative colitis (UC) treatment. The potential to estimate EI non-invasively is an advantage of intestinal ultrasound (IUS). In a previous study, we developed a new sonographic parameter, the submucosa index (SMI), calculated as the ratio of the submucosal thickness to bowel wall thickness (BWT), and reported that combining BWT and SMI results in a practical and promising criterion for estimating EI without color Doppler assessment. This study aimed to validate the EI estimation ability of our B mode-based criterion, the 'Kyorin Ultrasound Criterion for UC' (KUC-UC; BWT < 3.8 mm and SMI < 50%), using an external cohort.

METHODS

Patients with UC who underwent IUS and colonoscopy within 15 days without a treatment change between examinations were included. IUS findings, including BWT, SMI, and modified Limberg score for vascularity of the colon, were assessed.

RESULTS

Forty-four test pairs of IUS and colonoscopy examinations in a total of 122 colonic segments were analyzed. The KUC-UC showed positive predictive value (PPV) of 94.6% and negative predictive value (NPV) of 80.0% for EI. In comparison, PPV and NPV were 85.4% and 79.0%, respectively, for the common criterion BWT of < 3 mm, and 83.0% and 82.7% for the validated Milan Ultrasound Criteria (a score of ≤ 6.2).

CONCLUSIONS

External validation showed that the KUC-UC using only B mode findings without complicated calculations is a feasible and accurate sonographic criterion for estimating the EI of UC.

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.

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.

Leaving behind the Mucosa: Advances and Future Directions of Intestinal Ultrasound in Ulcerative Colitis

Inflammatory Bowel Diseases (IBD), mainly Ulcerative Colitis (UC) and Crohn's Disease (CD), are disorders characterized by chronic inflammation with severe morbidity and long-term disabling quality of life outcomes. UC mainly affects the mucosal and sub-mucosal layers of the colon, without embracing the peri-intestinal structures. Considering the predominant mucosal location of UC inflammation, the implementation of transmural evaluation by cross-sectional imaging techniques, mainly Intestinal Ultrasound (IUS), has been left behind for ages, especially if compared to CD. Nevertheless, studies analyzing intestinal ultrasound parameters accuracy in disease activity detection reported a good-to-optimal correlation of IUS markers with colonic inflammation, suggesting comparable feasibility of IUS monitoring in UC as in CD. The easy-to-use, costless and point-of-care available status of IUS is therefore crucial in order to improve the diagnostic process and, according to the recent literature, to monitor the response to treatment leading to speeding up decision making and therapy adjustments. Recent studies have demonstrated the correlation between transmural healing in UC with favorable outcomes even in the long term. An evidence gap still exists in the assessment of the rectum, with trans-perineal ultrasound (TPUS) a potential answer to reach a more precise evaluation of rectal inflammation. Eventually, IUS is also increasingly showing promises in emergent or post-surgical UC settings, considering various efforts put in line to demonstrate its feasibility in predicting response to salvage therapy for surgery avoidance and in studying inflammation relapse after procto-colectomy with ileo-pouch-anal anastomosis (IPAA) creation.

At-home Disease Monitoring by Patient-performed Intestinal Ultrasound in Severe Ulcerative Colitis

We describe the first reported case of a nonmedically trained patient using a handheld ultrasound device to monitor his ulcerative colitis in real time at home during induction therapy for severe colitis.

Milan Ultrasound Criteria Predict Relapse of Ulcerative Colitis in Remission

Introduction

Bowel ultrasound is a noninvasive alternative to endoscopy for assessing the disease activity of ulcerative colitis; however, it is unclear whether bowel ultrasound can predict subsequent relapse from remission.

Materials and Methods

A retrospective cohort study enrolled patients with ulcerative colitis who underwent bowel ultrasound between July 2018 and July 2021 during clinical remission (patient-reported outcome-2 ≤1 and no rectal bleeding) for at least 3 months and were followed up for 1 year. Ultrasonographic findings (bowel wall thickness, bowel wall flow, bowel wall stratification, and enlarged lymph nodes), Milan ultrasound criteria, Mayo endoscopic subscore, C-reactive protein, and fecal calprotectin levels and their association with subsequent clinical relapse were assessed. Relapse was defined as rectal bleeding score ≥1, stool frequency score ≥2, or treatment intensification for symptoms.

Results

31% of the patients (18/58) relapsed within 1 year. No single ultrasonographic finding predicted relapse, whereas Milan ultrasound criteria >6.2 (p = 0.019), Mayo endoscopic subscore ≥1 (p = 0.013), and fecal calprotectin ≥250 μg/g (p = 0.040) were associated with a shorter time to relapse in the log-rank test. Milan ultrasound criteria >6.2 (hazard ratio 3.22; 95% confidence interval 1.14-9.08, p = 0.027) and Mayo endoscopic subscore ≥1 (hazard ratio 8.70; 95% confidence interval 1.11-68.1, p = 0.039) showed a higher risk of relapse according to a Cox proportional hazards model.

Conclusion

Bowel ultrasound can predict subsequent clinical relapse from remission in patients with ulcerative colitis using the Milan ultrasound criteria.

Monitoring of Inflammatory Bowel Disease in Pregnancy: A Review of the Different Modalities

Inflammatory Bowel Disease (IBD) significantly affects women in their reproductive years. Understanding the relationship between IBD and pregnancy is crucial, given its impact across pre-gestational, gestational, and postpartum phases. Monitoring IBD activity during pregnancy involves various modalities. This review discusses these modalities, focusing on the efficacy and safety of Small Intestine Ultrasound (IUS) as a noninvasive and reliable option. While IUS has gained popularity, its technique-sensitive nature necessitates trained staff for optimal usage.

Bedside Intestinal Ultrasound Performed in an Inflammatory Bowel Disease Urgent Assessment Clinic Improves Clinical Decision-Making and Resource Utilization

Background

Patients with inflammatory bowel disease (IBD) require accessible, timely, and noninvasive strategies to monitor disease. The aim was to assess the integration of intestinal ultrasound (IUS) on decision-making and endoscopy utilization in a standardized care pathway.

Methods

This prospective, multicenter, international, observational cohort study included patients seen within a centralized model for IBD care was conducted during the COVID pandemic. Patients were evaluated with IUS alone or in combination with an in-clinic, unsedated sigmoidoscopy. Demographic, clinical, laboratory, and imaging data, clinical decisions, and need for urgent endoscopy, hospitalization, and surgeries were recorded.

Results

Of the 158 patients included, the majority had an established diagnosis of Crohn's disease (n = 123, 78%), and 47% (n = 75) of patients were on biologic therapy. IUS identified active inflammation in 65% (n = 102) of patients, and strictures in 14% (n = 22). Fecal calprotectin levels correlated with inflammation detected on IUS (median of 50 μg/g [Q1-Q3: 26-107 μg/g] without inflammation and 270 μg/g [Q1-Q3: 61-556 μg/g] with inflammation; p = 0.0271). In the majority of patients, clinical assessment with IUS led to an acute change in IBD-specific medications (57%, n = 90) and avoided or delayed the need for urgent endoscopy (85%, n = 134). Four patients were referred for urgent surgical consultation.

Conclusions

Point-of-care IUS used in a flare clinic pathway is a useful strategy to improve effective IBD care delivery and to assist in therapeutic management decisions, in many cases avoiding the acute need for endoscopy.

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

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

An open competition involving thousands of competitors failed to construct useful abstract classifiers for new diagnostic test accuracy systematic reviews

There are currently no abstract classifiers, which can be used for new diagnostic test accuracy (DTA) systematic reviews to select primary DTA study abstracts from database searches. Our goal was to develop machine-learning-based abstract classifiers for new DTA systematic reviews through an open competition. We prepared a dataset of abstracts obtained through database searches from 11 reviews in different clinical areas. As the reference standard, we used the abstract lists that required manual full-text review. We randomly splitted the datasets into a train set, a public test set, and a private test set. Competition participants used the training set to develop classifiers and validated their classifiers using the public test set. The classifiers were refined based on the performance of the public test set. They could submit as many times as they wanted during the competition. Finally, we used the private test set to rank the submitted classifiers. To reduce false exclusions, we used the Fbeta measure with a beta set to seven for evaluating classifiers. After the competition, we conducted the external validation using a dataset from a cardiology DTA review. We received 13,774 submissions from 1429 teams or persons over 4 months. The top-honored classifier achieved a Fbeta score of 0.4036 and a recall of 0.2352 in the external validation. In conclusion, we were unable to develop an abstract classifier with sufficient recall for immediate application to new DTA systematic reviews. Further studies are needed to update and validate classifiers with datasets from other clinical areas.

Recent advances in the use of ultrasound in Crohn's disease

INTRODUCTION

A clear consensus exists on the role of IUS for the assessment and monitoring of Crohn's disease (CD) in the 'treat-to-target' strategy.

AREAS COVERED

IUS is an accurate tool for the management of CD. It is noninvasive and well tolerated. IUS has good-to-optimal inter-operator reliability either for assessing disease activity or for evaluating treatment response, especially combining Bowel Wall Thickness (BWT) and Color Doppler Signals (CDS). IUS is able to evaluate transmural remission (TR), the ultimate goal of the 'treat-to-target' strategy. Several studies confirmed its accuracy in the assessment of the post-operative recurrence (POR). Thanks to recent advances in trans-perineal ultrasound technique (TPUS), it allows to characterize peri-anal disease and its complications. Small intestine contrast ultrasound (SICUS) and contrast-enhancement ultrasound (CEUS) may improve IUS performance, particularly in stricturing or penetrating CD. Ultrasound elastography (USE) is raising interest for its accuracy in differentiating CD phenotypes (fibrotic versus inflamed).

EXPERT OPINION

IUS is a pivotal step in the management of CD, in early assessment as in therapeutic monitoring, with advantages of evaluating transmural response. Development and validation of novel ultrasound biomarkers of activity and fibrosis, especially those linked to advanced ultrasound techniques, are expected in the coming years.

Small bowel imaging in inflammatory bowel disease: updates for 2023

INTRODUCTION

Cross-sectional imaging techniques including MR and CT enterography and ultrasound are integral to Crohn's disease management, accurate, responsive, and well tolerated. They assess the full thickness of the bowel wall, perienteric environment, and distant complications. As we strive toward tighter disease control, imaging's role will expand further with transmural healing becoming an increasingly important therapeutic target.

AREAS COVERED

MEDLINE and Web of Science were searched from 2012 to 2023 inclusive. We review the evidence for cross-sectional imaging in assessing disease activity, phenotyping, and therapeutic response assessment. Emerging novel imaging applications such as quantifying enteric motility and fibrosis, prognostication, and potential utility of artificial intelligence will be covered. Recent international consensus statements highlight the need for standardized imaging reporting and definitions of transmural healing and remission. We will discuss how recent advances may be best integrated into patient care and highlight key outstanding research questions.

EXPERT OPINION

Cross-sectional imaging is established in Crohn's disease management. Research emphasis should be placed on optimal integration of imaging modalities in clinical care pathways, workforce training, definitions, and evidence for use of imaging based therapeutic targets such as transmural healing, better phenotyping of stricturing disease, and developing novel techniques, including integration of artificial intelligence.

Intestinal Ultrasound in Inflammatory Bowel Disease: A Novel and Increasingly Important Tool

New and efficacious medical therapies have become available that have greatly enhanced clinicians' ability to manage inflammatory bowel diseases (IBDs). IBD activity should be assessed regularly in scheduled examinations as the part of a treat-to-target strategy for IBD care. The gold-standard approach to investigating IBD is colonoscopy, but this is an invasive procedure. Intestinal ultrasound (IUS) has played a crucial role in recent years regarding the assessment of IBD activity because it is noninvasive, safe, reproducible, and inexpensive. IUS findings could inform changes in therapeutic interventions for IBDs; this would necessitate fewer endoscopies and enable faster decision-making processes. Furthermore, patients are accepting and tolerant of IUS examinations. This review outlines the current evidence and gives indication regarding the use of IUS in the management of IBDs.

First aid with color atlas for the use of intestinal ultrasound for inflammatory bowel disease in daily clinical practice

Intestinal ultrasound (IUS) is a promising modality for the management of inflammatory bowel disease (IBD) and has the potential to particularly contribute in monitoring disease activity, an advantage crucial for optimizing the therapeutic strategy. While many IBD physicians appreciate and are interested in the use of IUS for IBD, currently only a limited number of facilities can employ this examination in daily clinical practice. A lack of guidance is one of the major barriers to introducing this procedure. Standardized protocols and assessment criteria are needed such that IUS for IBD can be considered a feasible, reliable examination in clinical practice, and multicenter clinical studies can be conducted for further clinical evidence of the application of IUS in IBD for best patient care. In this article, we provide an overview of how to start IUS for IBD and introduce basic procedures. Furthermore, IUS images from our practice are provided as a color atlas for understanding sonographic findings and scoring systems. We anticipate this "first aid" article will be helpful to promote IUS for IBD in daily practice.

Use of imaging modalities for decision-making in inflammatory bowel disease

Cross-sectional magnetic resonance enterography (MRE) and intestinal ultrasonography (IUS) provide valuable and noninvasive information to accurately assess disease activity, severity, and extent; detect complications; and monitor the response to treatment, as well as predict the postoperative recurrence of Crohn's disease and a negative disease course. Therefore, both imaging modalities are emerging as pivotal diagnostic tools to achieve the emerging therapeutic target of transmural healing associated with better disease outcomes. Despite its numerous potential advantages over endoscopy and even MRE and its good availability, IUS is still widely underused to monitor and manage inflammatory bowel disease (IBD) patients and help in making clinical decisions in routine practice. This situation is clearly due to the absence of validated, reliable, and responsive indices, as well as the lack of trained gastroenterologists and radiologists, as IUS is a component of radiologist expertise in several countries but not yet integrated into the training program of gastroenterologists. However, there is an increasing body of evidence in the literature that IUS and MRE are both becoming essential imaging resources to help clinicians in making reliable decisions. Here, we discuss the up-to-date evidence about the usefulness and performance of cross-sectional imaging, focusing on the ability of bowel US and MRE to aid clinical decision-making for the optimal management and monitoring of IBD.

Characteristics and usefulness of transabdominal ultrasonography in immune-mediated colitis

BACKGROUND/AIMS

The usefulness of ultrasonography (US) in diseases of the gastrointestinal tract has been reported recently. This prospective study aimed to determine the features of US findings in immune-mediated colitis (IMC), an adverse event induced by immune checkpoint inhibitor, and examine the correlation between US findings, colonoscopy (CS) findings, and severity of colitis.

METHODS

We studied patients examined using CS and US upon suspicion of IMC in Hokkaido University Hospital between April 2018 and February 2021. Endoscopic findings of IMC were assessed using the Ulcerative Colitis Endoscopic Index of Severity (UCEIS). The severity of US findings in IMC was evaluated using US grade, which is the ultrasonographic grading scale in ulcerative colitis. Bowel wall thickness and the intensity of the color Doppler signal were also analyzed. Severity of colitis was evaluated using Common Terminology Criteria for Adverse Events (CTCAE) grade version 5.

RESULTS

Fourteen patients with IMC were enrolled. The US findings were bowel wall thickening, loss of stratification, ulceration and increased blood flow signal. The US grade was moderately correlated with the UCEIS (r=0.687, p=0.009) and CTCAE grade (r=0.628, p=0.035). Bowel wall thickness and UCEIS (r=0.628, p=0.020), as well as color Doppler signal grade and CTCAE grade (r=0.724, p=0.008), were significantly correlated.

CONCLUSIONS

US findings in IMC were mainly similar to those of ulcerative colitis, but there were some findings that were characteristic only of IMC. Significant correlation was found between US findings, CS findings, and severity of colitis. Hence, US could be useful for the evaluation of IMC.

The use of ultrasound in colonic and perianal diseases

PURPOSE OF REVIEW

To revise recent literature findings regarding the use of ultrasound in colonic and perianal diseases by focusing particularly on its feasibility in inflammatory bowel diseases (IBD), colorectal neoplastic lesions, and perineal diseases, with further highlight on interventional capabilities.

RECENT FINDINGS

Treat-to-target approach in IBD raised an interest in intestinal ultrasound (IUS) for monitoring bowel activity considering its noninvasive nature, low costs, and well tolerability. New IUS indices have been developed with ever better methodologies and are at various stage of validation. A standardized over-the-wire technique for colonic US using a flexible overtube enables endoscopic ultrasound (EUS)-guided tissue sampling beyond the rectum, and forward-viewing radial-array echoendoscopes can assist identification of early neoplastic lesions in proximal colon. Intraoperative ultrasound and contrast-enhanced ultrasound carry an additional diagnostic value compared to conventional preoperative imaging modalities in detecting colorectal cancer liver metastases (CRLM).

SUMMARY

The feasibility of IUS in monitoring IBD activity is supported by growing evidence, but uniform IUS indices are still lacking. Recent advancements in EUS are expanding capabilities for determining depth of invasion of colorectal neoplasms, tissue sampling, and EUS-guided interventions to the entire colon. Ultrasonography can be a valuable tool in CRLM diagnostics as well.

Intestinal Ultrasound Is Accurate to Determine Endoscopic Response and Remission in Patients With Moderate to Severe Ulcerative Colitis: A Longitudinal Prospective Cohort Study

BACKGROUND & AIMS

Intestinal ultrasound (IUS) is noninvasive, cost-effective, and accurate to determine disease activity in ulcerative colitis (UC). In this study, we prospectively evaluated IUS for treatment response in a longitudinal cohort by using endoscopy and histology as gold standards.

METHODS

Consecutive patients with moderate to severe UC (endoscopic Mayo score [EMS] ≥2) starting tofacitinib treatment were included. Patients were evaluated at baseline and after 8 weeks of tofacitinib induction by means of clinical, biochemical, endoscopic (EMS and UC endoscopic index for severity), histologic (Robarts Histopathologic Index) and IUS assessments. Readers of IUS, endoscopy, and histology were blinded for all other outcomes. The primary outcome was difference in bowel wall thickness (BWT) for endoscopic improvement vs no endoscopic improvement. Endoscopic remission was defined as EMS = 0, improvement as EMS ≤1, and response as a decrease of EMS ≥1.

RESULTS

Thirty patients were included, with 27 patients completing follow-up. BWT correlated with EMS (ρ = 0.68, P < .0001), UC endoscopic index for severity (ρ = 0.73, P < .0001) and Robarts Histopathologic Index (ρ = 0.49, P = .002) at both time points. BWT in the sigmoid was lower in patients with endoscopic remission (1.4 mm vs 4.0 mm, P = .016), endoscopic improvement (1.8 mm vs 4.5 mm, P < .0001) and decrease in BWT was more pronounced in patients with endoscopic response (-58.1% vs -13.4%, P = .018). The most accurate cutoff values for BWT were 2.8 mm (area under the curve [AUC] 0.87) for endoscopic remission, 3.9 mm (AUC 0.92) for improvement, and decrease of 32% (AUC 0.87) for response. The submucosa was the most responsive wall layer.

CONCLUSION

IUS, importantly BWT as the single most important parameter, is highly accurate to detect treatment response when evaluated against endoscopic outcomes.

A Pictorial Review of Pelvic Pain-Beyond the Genitourinary System

ABSTRACT

Pelvic pain may be caused by disorders of the reproductive, urinary, or gastrointestinal systems. In the pediatric population, pelvic pain is often first evaluated with ultrasonography, with other imaging modalities reserved for further workup or specific indications. Radiologists must be aware of the findings associated with common pelvic emergencies to allow prompt diagnosis and prevention of life-threatening complications. Although the range of pelvic pathology is extensive, this pictorial review presents ultrasound examples of common nontraumatic causes of pelvic pain encountered in the pediatric population, with a brief discussion about multimodality imaging features.

Diagnostic Utility of Non-invasive Tests for Inflammatory Bowel Disease: An Umbrella Review

Background

This study aims to consolidate evidence from published systematic reviews and meta-analyses evaluating the diagnostic performances of non-invasive tests for inflammatory bowel disease (IBD) in various clinical conditions and age groups.

Methods

Two independent reviewers systematically identified and appraised systematic reviews and meta-analyses assessing the diagnostic utility of non-invasive tests for IBD. Each association was categorized as adults, children, and mixed population, based on the age ranges of patients included in the primary studies. We classified clinical scenarios into diagnosis, activity assessment, and predicting recurrence.

Results

In total, 106 assessments from 43 reviews were included, with 17 non-invasive tests. Fecal calprotectin (FC) and fecal lactoferrin (FL) were the most sensitive for distinguishing IBD from non-IBD. However, anti-neutrophil cytoplasmic antibodies (ANCA) and FL were the most specific for it. FC and FL were the most sensitive and specific tests, respectively, to distinguish IBD from irritable bowel syndrome (IBS). Anti-Saccharomyces cerevisiae antibodies (ASCA), IgA, were the best test to distinguish Crohn’s disease (CD) from ulcerative colitis (UC). Interferon-γ release assay was the best test to distinguish CD from intestinal tuberculosis (ITB). Ultrasound (US) and magnetic resonance enterography (MRE) were both sensitive and specific for disease activity, along with the high sensitivity of FC. Small intestine contrast ultrasonography (SICUS) had the highest sensitivity, and FC had the highest specificity for operative CD recurrence.

Conclusion

In this umbrella review, we summarized the diagnostic performance of non-invasive tests for IBD in various clinical conditions and age groups. Clinicians can use the suggested non-invasive test depending on the appropriate clinical situation in IBD patients.

The Impact of Intestinal Ultrasound on the Management of Inflammatory Bowel Disease: From Established Facts Toward New Horizons

Intestinal ultrasound (IUS) plays a crucial role as a non-invasive and accurate tool to diagnose and assess inflammatory bowel disease (IBD). The rationale for using IUS in Crohn’s disease (CD), a transmural disease, is widely acknowledged. While the use of IUS in ulcerative colitis (UC), a mucosal disease, is often underestimated, but, recently, it is increasingly expanding. In the context of a treat-to-target approach, the role of IUS is shifting toward a monitoring tool for predicting response to therapy. Hence, adjusting therapeutic strategies based on IUS response could reduce the burden related to endoscopy and speed the decision process with the ultimate goal to alter the natural course of IBD. Assessment of bowel wall thickness (BWT) is the most reliable IUS measure. However, the development of validated and reproducible sonographic scores to measure disease activity and the identification of parameters of therapeutic response remain relevant issues to implement the daily adoption of IUS in clinical practice. Accordingly, this review focuses on the current literature investigating the impact of IUS on CD with emphasis on the concept of transmural healing (TH) and the main related advantages. We further explore new insights on the role of IUS in UC and its clinical implications.

Early improvement in bowel wall thickness on transperineal ultrasonography predicts treatment success in active ulcerative colitis

BACKGROUND

Bowel ultrasonography is a non-invasive imaging tool that can repeatedly monitor ulcerative colitis (UC) activity.

AIM

This study aimed to determine whether early transabdominal or transperineal ultrasonography changes can predict subsequent clinical response to induction therapy in patients with UC.

METHODS

This single-centre prospective study explored ultrasonographic predictors for clinical remission (patient-reported outcome-2 ≤ 1 with no rectal bleeding subscore) at week 8 in patients with active UC who underwent induction therapy, in comparison with faecal calprotectin and C-reactive protein (measured at baseline, week 1 and week 8). Predictive factors were assessed using multivariable regression models and receiver-operating-characteristic curve analysis.

RESULTS

A total of 100 patients were analysed, of which 54 achieved remission at week 8. Baseline biomarker and ultrasonographic-parameter values were not predictive of remission. Contrastingly, change from baseline to week 1 in rectal bowel wall thickness measured using transperineal ultrasonography was an independent predictor of remission by week 8 (adjusted odds ratio is associated with a 1-mm decrease: 1.90 [95% confidence interval, 1.22-2.95]). In a subgroup analysis of the patients who did not achieve remission in 1 week, the predictive value of change in rectal bowel wall thickness remained high (AUC = 0.77 [95% confidence interval, 0.61-0.88]).

CONCLUSION

Improvement in rectal bowel wall thickness measured using transperineal ultrasonography at week 1 predicts treatment success and potentially facilitates decision making during the early course of induction therapy in UC.

Ratio of submucosal thickness to total bowel wall thickness as a new sonographic parameter to estimate endoscopic remission of ulcerative colitis

BACKGROUND

The development of feasible, reliable parameters and criteria for intestinal ultrasound (IUS) to estimate endoscopic remission of ulcerative colitis (UC) is a crucial clinical challenge. Such parameters must be simple, objective, and reproducible so that IUS can be widely used in daily practice. We developed a new parameter called the submucosa index (SMI), defined as a percentage of the submucosal thickness (SMT) in the total bowel wall thickness (BWT), and investigated its clinical potential.

METHODS

The inclusion criteria were performance of both IUS and endoscopy (sigmoidoscopy or colonoscopy) for UC and a ≤ 15-day time interval between IUS and endoscopy. Loss of stratification was defined as inability to identify the submucosa even with a BWT of > 3 mm. The vascularity of the colon was assessed by the modified Limberg score (mLS) and evaluated as bowel wall flow (BWF) ( -) or ( +) using color Doppler mode. A Mayo endoscopic subscore (MES) of 0 or 1 was defined as endoscopic remission.

RESULTS

Seventy-four colonic segments were analyzed. The SMI, mLS, and BWF could distinguish an MES of 1 versus 2 (p < 0.05, p < 0.01, and adjusted p < 0.001, respectively). The criteria using the BWT and SMI and using the BWT and BWF had the same estimating ability for endoscopic remission (sensitivity, 70.0%; specificity, 97.7%; positive predictive value, 95.5%; and negative predictive value, 82.7%).

CONCLUSION

The SMI is a practical, quantitative parameter based on the bowel wall structure and may be used to estimate endoscopic remission of UC.

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

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

Insights into the role of gastrointestinal ultrasound in ulcerative colitis

Endoscopic evaluation with histological sampling is the gold standard for the diagnosis and follow-up of patients with inflammatory bowel disease (IBD), but in the past few years, gastrointestinal ultrasound (GIUS) has been gaining ground. Due to the transmural nature of inflammation in Crohn's disease, GIUS has been mainly applied in this context. However, GIUS is now being reported to be accurate also for ulcerative colitis (UC). This review summarizes current knowledge on the use of GIUS in UC, with a focus on clinical practice. The review covers topics such as GIUS parameters, especially bowel wall thickness; the use of GIUS in assessing disease extent and in monitoring disease activity; GIUS indexes and scores; and the combination of GIUS with transperineal ultrasound for a better assessment of the rectum. With the always growing body of evidence supporting the accuracy of GIUS in UC, this diagnostic imaging modality can be expected to play a bigger role in disease flare evaluation, early treatment monitoring, and acute severe disease management.

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.

Bowel ultrasound enhances predictive value based on clinical indicators: a scoring system for moderate-to-severe endoscopic activities in patients with ulcerative colitis

BACKGROUND AND AIM

The aim was to assess non-invasive factors among clinical features, laboratory, and bowel ultrasound (BUS) characteristics and to develop a scoring system to predict endoscopic activities for ulcerative colitis (UC) patients.

METHODS

We performed a retrospective study collecting UC patients between January 2015 to September 2020. Logistic regression was performed to predict moderate-to-severe endoscopic activities, defined as endoscopic Mayo score ⩾2. Model performance was described with discrimination and calibration ability and validated by internal and external methods.

RESULTS

A total of 103 and 29 patients were enrolled in the modeling and validation groups, respectively. Stool frequency ⩾5 times/day, hematochezia, erythrocyte sedimentation rate (ESR), and colonic wall flow in BUS were included into two predictive models for endoscopic activities, both with good discrimination ability [Area under curve (AUC) 0.879 and 0.882, p < 0.001] and a sensitivity of 76.7% and specificity of 92.3%, which showed an adequate calibration ability by using the Hosmer-Lemeshow test (p = 0.14 and 0.07). The external validation displayed consistent results with the above mentioned. Nomograms were also established for these models.

CONCLUSION

We developed predictive models for endoscopic disease activities by using noninvasive factors based on stool frequency, hematochezia, ESR, and colonic wall blood flow in BUS. These models performed well in the internal and external validation.

A Reliability Study: Strong Inter-Observer Agreement of an Expert Panel for Intestinal Ultrasound in Ulcerative Colitis

BACKGROUND

Intestinal ultrasound [IUS] is a promising and non-invasive cross-sectional imaging modality in the diagnosis and monitoring of ulcerative colitis [UC]. Unlike endoscopy, where standardized scoring for evaluation of disease activity is widely used, scoring for UC with IUS is currently unavailable. Therefore, we conducted a study to assess the reliability of IUS in UC among expert sonographists in order to identify robust parameters.

METHODS

Thirty patients with both clinically active [25] and quiescent [five] UC were included. Six expert sonographers first agreed upon key IUS parameters and grading, including bowel wall thickness [BWT], colour Doppler signal [CDS], inflammatory fat [i-fat], loss of bowel wall stratification [BWS], loss of haustrations and presence of lymph nodes. Thirty video-recorded cases were blindly reviewed.

RESULTS

Inter-observer agreement was almost perfect for BWT (intra-class correlation coefficient [ICC]: 0.96) and substantial for CDS [κ = 0.63]. Agreement was moderate for presence of lymph nodes [κ = 0.41] and fair for presence of i-fat [κ = 0.36], BWS [κ = 0.24] and loss of haustrations [κ = 0.26]. Furthermore, there was substantial agreement for presence of disease activity on IUS [κ = 0.77] and almost perfect agreement for disease severity [ICC: 0.93]. Most individual parameters showed a strong association with IUS disease activity as measured by the six readers.

CONCLUSION

IUS is a reliable imaging modality to assess disease activity and severity in UC. Important individual parameters such as BWT and CDS are reliable and could be incorporated in a future UC scoring index. Standardized acquisition and assessment of UC utilizing IUS with established reliability is important to expand the use of IUS globally.