Point-of-Care Ultrasound in Inflammatory Bowel Disease

Diagnostic Accuracy of Intestinal Ultrasound in the Detection of Intra-Abdominal Complications in Crohn's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Crohn's disease [CD] is frequently associated with the development of strictures and penetrating complications. Intestinal ultrasound [IUS] is a non-invasive imaging modality ideal for point-of-care assessment. In this systematic review and meta-analysis we provide a current overview on the diagnostic accuracy of IUS and its advanced modalities in the detection of intra-abdominal complications in CD compared to endoscopy, cross-sectional imaging, surgery, and pathology.

METHOD

We conducted a literature search for studies describing the diagnostic accuracy of IUS in adult patients with CD-related intra-abdominal complications. Quality of the included studies was assessed with the QUADAS-2 tool. Meta-analysis was performed for both conventional IUS [B-mode] and oral contrast IUS [SICUS].

RESULTS

Of the 1498 studies we identified, 68 were included in this review and 23 studies [3863 patients] were used for the meta-analysis. Pooled sensitivities and specificities for strictures, inflammatory masses, and fistulas by B-mode IUS were 0.81 and 0.90, 0.87 [sensitivities] and 0.95, and 0.67 and 0.97 [specificities], respectively. Pooled overall log diagnostic odds ratios were 3.56, 3.97 and 3.84, respectively. Pooled sensitivity and specificity of SICUS were 0.94 and 0.95, 0.91 and 0.97 [sensitivities], and 0.90 and 0.94 [specificities], respectively. The pooled overall log diagnostic odds ratios of SICUS were 4.51, 5.46, and 4.80, respectively.

CONCLUSION

IUS is accurate for the diagnosis of intra-abdominal complications in CD. As a non-invasive, point-of-care modality, IUS is recommended as the first-line imaging tool if there is a suspicion of CD-related intra-abdominal complications.

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.

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). Predictive capabilities of intestinal ultrasound (IUS) for T2T ER remains unknown. We aimed to evaluate IUS response to predict ER in children with CD.

METHODS

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. 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 analysis was performed and univariate analysis tested associations.

RESULTS

44 children (median age 13 [IQR 12-17] years, 29 (66%) biologic naïve) were included, 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% PPV, and 100% NPV, 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 strategy.

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.

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.

Assessing Active Bowel Inflammation in Crohn's Disease Using Intestinal Ultrasound: Correlation With Fecal Calprotectin

AIM

To analyze the correlation between intestinal ultrasound (IUS) and serum and fecal biomarkers, and the characteristics of small bowel disease, for the assessment of active bowel inflammation.

METHODS

Patients with Crohn's disease (CD) who underwent an initial IUS examination between July 2018 and November 2022 at our institution were included retrospectively. We divided small and large bowels into seven segments, and recorded the presence of active inflammation according to following criteria: bowel wall thickness ≥ mm with ≥1 of feature of active disease on IUS. The correlations between IUS-assessed activity and serum C-reactive protein (CRP, mg/dL) and fecal calprotectin (FC, μg/g) levels were analyzed.

RESULTS

A total of 127 patients were included (mean age: 32.42 ± 12.07, M:F = 90:37, median disease duration 6 years [0-35]). Of them, 78 showed active bowel inflammation (61.4%), with inflammation distal to the terminal ileum being the most common disease location (n = 61, 78.2%). FC and serum CRP levels were significantly correlated with the number of segments with active inflammation (rho = 0.58, 0.48), number of segments with complications (r = 0.35, 0.31), and US activity score (r = 0.62, 0.54). With FC cutoff values of 100 and 150 μg/g, the concordance rates for patients with active small bowel disease were 78.7% (26/33) and 72.7% (24/33), respectively, which were better than those for other disease locations.

CONCLUSIONS

Disease activity determined by IUS was significantly correlated with the biomarkers, with a better concordance rate in patients with active small bowel disease than in those with other disease locations with FC cut-off values of 100 and 150 μg/g.

Small Bowel Imaging in Celiac Disease: Is there a role for Small Bowel Ultrasound?

PURPOSE OF REVIEW

The incidence of celiac disease (CD) has increased over the last decades in part due to better disease awareness. Small bowel ultrasound (sb US) enables dynamic assessment of the bowel; although this topic has been addressed, the use of sb US in the diagnosis and in the follow-up of CD patients is limited to a few specialized tertiary referral centers. Herein, we aimed at summarizing the available literature on this topic to better define the potential clinical implications of sb US in CD, also through a comparison with other available diagnostic techniques.

RECENT FINDINGS

According to available data, sb US can be of help in confirming or excluding CD in patients with clinical suspicion; specifically, the finding of increased gall bladder volume, free abdominal fluid and enlargement of mesenteric lymph nodes reliably and accurately predicts the diagnosis of CD, whereas the absence of bowel dilatation and increased peristalsis may exclude the diagnosis. However, the place of intestinal US in the diagnostic algorithm of CD is likely to vary depending on the probability of the disease in a given population. There are only a few studies on the role of sb US in complicated CD, even if recent reports suggest a possible clinical role. There is a lack of data on follow-up of CD patients, particularly with the aim of detecting a poor diet adherence. According to current data sb US parameters have been shown to be of value in confirming and excluding the diagnosis of CD. Prospective studies with large sample size are warranted to determine whether to include sb US in the available guidelines for CD diagnosis and monitoring.

Early Intestinal Ultrasound Predicts Long-Term Endoscopic Response to Biologics in Ulcerative Colitis

BACKGROUND AND AIMS

The Milan ultrasound criteria [MUC] is a validated score to assess endoscopic activity in ulcerative colitis [UC]. MUC > 6.2 detects Mayo endoscopic score [MES] > 1. In this study we evaluated the predictive value of MUC for biologic treatment response, using colonoscopy [CS] as a reference standard.

METHODS

Consecutive UC patients starting biologic therapy were included, and underwent CS, IUS, clinical assessment and faecal calprotectin [FC] measurement at baseline and within 1 year. In addition, IUS, clinical and FC assessments were performed at week 12. The primary objective was to evaluate whether ultrasound improvement [MUC ≤ 6.2] at week 12 predicted endoscopic improvement at reassessment [MES ≤ 1]. Endoscopic remission was defined as MES = 0.

RESULTS

Forty-nine patients were included [59% under infliximab, 29% under vedolizumab, 8% under adalimumab, 4% under ustekinumab]. MUC ≤ 6.2 at week 12 was the only independent predictor for MES ≤ 1 and MES = 0 at reassessment (odds ratio [OR] 5.80, p = 0.010; OR 10.41, p = 0.041; respectively). MUC ≤ 6.2 at week 12 showed a negative predictive value of 96% for detecting MES = 0. A ≥2 reduction of the MUC predicted MES = 0 (area under the curve [AUC] 0.816). MUC ≤ 4.3 was the most accurate cut-off value for MES = 0 [AUC 0.876]. Guyatt's responsiveness ratio for the MUC was 1.73 [>0.8].

CONCLUSION

MUC ≤ 6.2 at week 12 predicts long-term endoscopic response. MUC is accurate in monitoring treatment response and may be used in both clinical trials and routine practice.

Intestinal Ultrasound Combined with Blood Inflammatory Markers Is a More Efficient Tool in Evaluating Severity of Crohn's Disease: A Pilot Study

Background and Aims

Intestinal ultrasound (IUS) is considered a nonirradiating, noninvasive, well-tolerated, and valuable tool for objectively assessing Crohn's disease (CD) activity. However, there is no widely accepted intestinal ultrasound scoring system. This study is aimed at evaluating the efficacy of IUS key parameters, the International Bowel Ultrasound Activity Score (IBUS-SAS), and IBUS-SAS combined with blood inflammatory markers in assessing CD activity.

Methods

40 CD patients were reviewed in this retrospective study and were divided into the moderate-severe group (n = 25) and nonmoderate-severe group (n = 15) based on a simplified endoscopic score of Crohn's disease (SES-CD). Double-balloon enteroscopy/colonoscopy were reviewed by three gastroenterologists. A transabdominal ultrasound was performed by two ultrasound specialists. Blood inflammatory markers were measured from morning samples.

Results

In evaluating moderate to severe CD patients, (1) IBUS-SAS had a good predictive effect with an area-under-the-curve (AUC) of 0.855 (P < 0.001); (2) IUS key parameters (including BWT, CDS, BWS, and I-fat) yielded good predictive effects with AUC of 0.811, 0.731, 0.724, and 0.747, respectively (P < 0.001); (3) blood inflammatory markers (including ESR, CRP, PLR, MLR, and NLR) also had good predictive effects with AUC of 0.771, 0.837, 0.728, 0.743, and 0.775, respectively (P < 0.001); (4) IBUS-SAS combined with ESR and CRP exerted the best predictive effect with the highest AUC of 0.912 (95% CI: 0.823-1.000), and the sensitivity and specificity were 88.0% and 80.0%, respectively (P < 0.001).

Conclusion

IBUS-SAS combined with ESR and CRP is a more efficient tool than IBUS-SAS alone or inflammatory markers alone in evaluating CD patients with moderate to severe disease activity.

Noninvasive Assessment of Postoperative Disease Recurrence in Crohn's Disease: A Multicenter, Prospective Cohort Study on Behalf of the Italian Group for Inflammatory Bowel Disease

BACKGROUND & AIMS

Colonoscopy (CS) is the gold standard to assess postoperative recurrence (POR) in Crohn's disease (CD). However, CS is invasive and may be poorly tolerated by patients. The aim of this study was to prospectively assess the diagnostic accuracy of a noninvasive approach in detecting POR, using the endoscopic Rutgeerts' score (RS) as the reference standard.

METHODS

Consecutive patients with CD who underwent ileo-cecal resection were prospectively enrolled in 3 referral Italian centers. Patients underwent CS and bowel ultrasound within 1 year of surgery. Uni- and multivariable analyses were used to assess the correlation between noninvasive parameters and endoscopic recurrence, defined by a RS ≥2.

RESULTS

Ninety-one patients were enrolled. Sixty patients (66%) experienced endoscopic POR. The multivariable analysis identified bowel wall thickness (BWT) per 1-mm increase (odds ratio [OR], 2.43; 95% confidence interval [CI], 1.21-4.89; P = .012), the presence of mesenteric lymph nodes (OR, 15.63; 95% CI, 1.48-164.54; P = .022), and fecal calprotectin (FC) values ≥50 mcg/g (OR, 8.58; 95% CI, 2.45-29.99; P < .001) as independent predictors for endoscopic recurrence. The presence of lymph nodes or the combination of BWT ≥3 mm and FC values ≥50 mcg/g correctly classified 56% and 75% of patients, with less than 5% of patients falsely classified as having endoscopic recurrence. Conversely, the combination of BWT <3 mm and FC <50 mcg/g correctly classified 74% of patients with only 4.5% of patients falsely classified as not having endoscopic recurrence.

CONCLUSIONS

A noninvasive approach combining bowel ultrasound and FC can be used with confidence for detecting POR in patients with CD without the requirement for CS.

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.

Results of the Eighth Scientific Workshop of ECCO: Diagnosing Postoperative Recurrence of Crohn's Disease After an Ileocolonic Resection With Ileocolonic Anastomosis

Despite the introduction of potent biologic therapies, many patients with Crohn's disease [CD] still require an ileocolonic resection [ICR] during the course of their disease. Furthermore, the need of redo ICR has not decreased over the past few decades, highlighting the need for better strategies to prevent and treat postoperative recurrence [POR]. The first step to develop such a strategy would be to define and standardise the description of POR with adequate diagnostic instruments. In this article, we will describe the different methodologies used to report POR [endoscopic, histological, radiological, biochemical, clinical, and surgical], and review their potential benefits and limitations, as well as the optimal timing of evaluation.

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.

The 2023 Impact of Inflammatory Bowel Disease in Canada: Access to and Models of Care

Rising compounding prevalence of inflammatory bowel disease (IBD) (Kaplan GG, Windsor JW. The four epidemiological stages in the global evolution of inflammatory bowel disease. Nat Rev Gastroenterol Hepatol. 2021;18:56-66.) and pandemic-exacerbated health system resource limitations have resulted in significant variability in access to high-quality, evidence-based, person-centered specialty care for Canadians living with IBD. Individuals with IBD have identified long wait times, gaps in biopsychosocial care, treatment and travel expenses, and geographic and provider variation in IBD specialty care and knowledge as some of the key barriers to access. Care delivered within integrated models of care (IMC) has shown promise related to impact on disease-related outcomes and quality of life. However, access to these models is limited within the Canadian healthcare systems and much remains to be learned about the most appropriate IMC team composition and roles. Although eHealth technologies have been leveraged to overcome some access challenges since COVID-19, more research is needed to understand how best to integrate eHealth modalities (i.e., video or telephone visits) into routine IBD care. Many individuals with IBD are satisfied with these eHealth modalities. However, not all disease assessment and monitoring can be achieved through virtual modalities. The need for access to person-centered, objective disease monitoring strategies, inclusive of point of care intestinal ultrasound, is more pressing than ever given pandemic-exacerbated restrictions in access to endoscopy and cross-sectional imaging. Supporting learning healthcare systems for IBD and research relating to the strategic use of innovative and integrative implementation strategies for evidence-based IBD care interventions are greatly needed. Data derived from this research will be essential to appropriately allocating scarce resources aimed at improving person-centred access to cost-effective IBD care.

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.

Stakeholder-identified barriers and enablers to ultrasound implementation in inflammatory bowel disease services in the UK: a qualitative interview study

OBJECTIVES

The study sought to explore and better understand the perceptions and experiences of stakeholders in relation to the use of ultrasound for the assessment of inflammatory bowel disease (IBD) in adults in the UK.

DESIGN

A qualitative semistructured interview study, using template analysis and normalisation process theory, was undertaken.

SETTING

Interviews were conducted using virtual meeting software.

RESULTS

Fourteen participants were enrolled between 2nd of June 2021 and 6th of September 2021. Participants were from the following roles: medical gastroenterology and radiology doctors, IBD nurse specialists, patients living with IBD, healthcare service managers. Participants reported that perceived barriers included reliance on established imaging and care pathways, reluctance to change, lack of trust in ultrasound in relation to perceived lack of precision and the initial financial and time outlay in establishing an ultrasound service. Participants were enthusiastic for the uptake of ultrasound and discussed enablers to ultrasound uptake including the benefits to patients in terms of reduction in waiting times and earlier diagnosis and treatment allocation, reduced number of hospital appointments and patients having better understanding of their health.

CONCLUSION

There are perceived barriers to achieving implementation of ultrasound. There is scant literature to effectively assess these reported barriers. Therefore, there is further research required in the areas of the impact of the use of ultrasound for the assessment of IBD in the UK.

Aptamer-Functionalized Microbubbles Targeted to P-selectin for Ultrasound Molecular Imaging of Murine Bowel Inflammation

PURPOSE

Our objectives were to develop a targeted microbubble with an anti-P-selectin aptamer and assess its ability to detect bowel inflammation in two murine models of acute colitis.

PROCEDURES

Lipid-shelled microbubbles were prepared using mechanical agitation. A rapid copper-free click chemistry approach (azide-DBCO) was used to conjugate the fluorescent anti-P-selectin aptamer (Fluor-P-Ap) to the microbubble surface. Bowel inflammation was chemically induced using 2,4,6-trinitrobenzenesulfonic acid (TNBS) in both Balb/C and interleukin-10-deficient (IL-10 KO) mice. Mouse bowels were imaged using non-linear contrast mode following an i.v. bolus of 1 × 10⁸ microbubbles. Each mouse received a bolus of aptamer-functionalized and non-targeted microbubbles. Mouse phenotypes and the presence of P-selectin were validated using histology and immunostaining, respectively.

RESULTS

Microbubble labelling of Fluor-P-Ap was complete after 20 min at 37 ̊C. We estimate approximately 300,000 Fluor-P-Ap per microbubble and confirmed fluorescence using confocal microscopy. There was a significant increase in ultrasound molecular imaging signal from both Balb/C (p = 0.003) and IL-10 KO (p = 0.02) mice with inflamed bowels using aptamer-functionalized microbubbles in comparison to non-targeted microbubbles. There was no signal in healthy mice (p = 0.4051) using either microbubble.

CONCLUSIONS

We constructed an aptamer-functionalized microbubble specific for P-selectin using a clinically relevant azide-DBCO click reaction, which could detect bowel inflammation in vivo. Aptamers have potential as a next generation targeting agent for developing cost-efficient and clinically translatable targeted microbubbles.

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.

Imaging Evaluation of Inflammatory Bowel Disease Complications

Inflammatory bowel disease (IBD) is a chronic inflammatory condition that can progress to fibrostenotic and penetrating complications. Cross-sectional imaging is often needed for accurate diagnosis of IBD complication and for planning the appropriate management strategy. Computed tomography enterography, magnetic resonance enterography, and IBD ultrasound have become key tools for clinicians and interventional endoscopists. This article highlights and discusses various radiologic imaging techniques and their application to the diagnosis and management of IBD complications.

Toward transmural healing: Sonographic healing is associated with improved long-term outcomes in patients with Crohn's disease

BACKGROUND AND AIMS

Transmural healing has emerged as a treatment target in Crohn's disease (CD). We investigated whether transmural healing assessed with intestinal ultrasound (IUS) is associated with improved clinical outcomes in patients with CD in clinical remission.

METHODS

Patients with CD in clinical remission at baseline (HBI <4) having IUS between August 2017 and June 2020 with at least 6-months' follow-up were retrospectively studied. Time to medication escalation, corticosteroid use and CD-related hospitalisation or surgery were compared by the presence or absence of sonographic healing, defined as bowel wall thickness ≤3 mm without hyperemia on color Doppler, inflammatory fat, or disrupted bowel wall stratification. Factors associated with survival were analyzed by Kaplan-Meier analysis using Cox proportional-hazard model.

RESULTS

Of 202 consecutive patients (50% male), sonographic inflammation was present in 61%. During median follow-up of 19 (IQR 13-27) months, medication escalation occurred in 52%, corticosteroid use in 23%, hospitalisation in 21%, and CD-related surgery in 13%. Sonographic healing was significantly associated with a reduced risk of medication escalation (p = 0.0018), corticosteroid use (p = 0.0247), hospitalisation (p = 0.0102), and surgery (p = 0.083). On multivariable analysis, sonographic healing was significantly associated with an increased odds of medication escalation-free survival (hazard ratio [HR]:1.94; 95% CI 1.23-3.06; p = 0.004) and corticosteroid-free survival (HR:2.41; 95% CI 1.24-4.67; p = 0.009), but not with hospitalisation or surgery.

CONCLUSION

In patients with CD in clinical remission, sonographic healing is associated with improved clinical outcomes. Further studies are needed to determine whether sonographic healing should be a treatment target.

David Against Goliath: Direct Comparison of Handheld Bowel Sonography and Magnetic Resonance Enterography for Diagnosis of Crohn's Disease

BACKGROUND

Diagnosis of Crohn's disease (CD) requires ileo-colonoscopy (IC) and cross-sectional evaluation. Recently, "echoscopy" has been used effectively in several settings, although data about its use for CD diagnosis are still limited. Our aim was to evaluate the diagnostic accuracy of handheld bowel sonography (HHBS) in comparison with magnetic resonance enterography (MRE) for CD diagnosis.

METHODS

From September 2019 to June 2021, we prospectively recruited consecutive subjects attending our third level IBD Unit for suspected CD. Patients underwent IC, HHBS, and MRE in random order with operators blinded about the result of the other procedures. Bivariate correlation between MRE and HHBS was calculated by Spearman coefficient (r). To test the consistency between MRE and HHBS for CD location and complications, the Cohen's k measure was applied.

RESULTS

Crohn's disease diagnosis was made in 48 out of 85 subjects (56%). Sensitivity, specificity, positive predictive values, and negative predictive values for CD diagnosis were 87.50%, 91.89%, 93.33%, and 85% for HHBS; and 91.67%, 94.59%, 95.65%, and 89.74% for MRE, without significant differences in terms of diagnostic accuracy (89.41% for HHBS vs 92.94% for MRE, P = NS). Magnetic resonance enterography was superior to HHBS in defining CD extension (r = 0.67; P < .01) with a better diagnostic performance than HHBS for detecting location (k = 0.81; P < .01), strictures (k = 0.75; P < .01), abscesses (k = 0.68; P < .01), and fistulas (k = 0.65; P < .01).

CONCLUSION

Handheld bowel sonography and MRE are 2 accurate and noninvasive procedures for diagnosis of CD, although MRE is more sensitive in defining extension, location, and complications. Handheld bowel sonography could be used as effective ambulatory (or out-of-office) screening tool for identifying patients to refer for MRE examination due to high probability of CD diagnosis.

Imaging in inflammatory bowel disease: current and future perspectives

The use of cross-sectional imaging and ultrasonography has long complemented endoscopic assessment of inflammatory bowel disease (IBD). Clinical symptoms alone are often not enough to assess disease activity, so a reliance on non-invasive techniques is essential. In this paper, we aim to examine the current use of radiological modalities in aiding the management of patients with IBD. We focus on the various sections of the gastrointestinal tract and how different modalities can aid in assessing current disease state and response to treatments. We also have a look at how newer sequences in cross-sectional imaging and ultrasonography can allow for better differentiation of disease activity (ie, fibrotic vs inflammatory) as well improve evaluation of small bowel, colonic and perianal disease. Furthermore, we examine how advanced image processing has the potential to allow radiology to be a surrogate for biomarkers. An example of this is explored when reviewing the ability of MR sequences to quantify visceral fat, which potentially plays a role in determining disease activity in Crohn's disease. Lastly, we look into the expected role for artificial intelligence to be used as an adjunct to radiology to better improve IBD evaluation.

Tools for the Diagnosis and Management of Crohn's Disease

Numerous tools have emerged over recent decades to aid in the increasingly complex management of patients with Crohn's disease (CD) beyond endoscopy, including video capsule endoscopy, magnetic resonance enterography, computed tomography enterography, a variety of biomarkers, and even wearable biosensors and smartphone applications. These tools have allowed for a more sophisticated and less invasive complementary approach to the evaluation of disease activity and treatment response in patients with CD. This article details the characteristics, practical application, and limitations of these various modalities and discusses how updated guidelines are now incorporating many of them into a treat-to-target strategy.

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

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

Predictive Value of Bowel Ultrasound in Crohn's Disease: A 12-Month Prospective Study

BACKGROUND & AIMS

Mucosal healing is associated with better outcomes in Crohn's disease (CD). Colonoscopy is invasive and poorly tolerated. Bowel ultrasound (US) is a noninvasive tool that increasingly is being used for CD assessment. We assessed the predictive role of baseline bowel US findings on disease course in a large prospective cohort of CD patients for 12 months.

METHODS

Ileocolonic CD consecutive patients were followed up for 12 months after performing bowel US. The negative course of CD, defined as the need for steroids and/or change of therapy and/or hospitalization and/or the need for surgery, was assessed. We evaluated this composite end point and subsequently considered each individual end point separately. Predictors of negative disease course were analyzed by logistic regression analysis.

RESULTS

There were 225 ileal and/or colonic CD consecutive patients included in the study. We analyzed the association between baseline bowel US parameters and endoscopic activity (defined as a Simplified Endoscopic Activity score for CD > 2) to set up a noninvasive quantitative ultrasound-based score (bowel ultrasound score). The multivariable analysis identified the following independent predictors of a worse outcome throughout the 12-month period as follows: bowel ultrasound score greater than 3.52 (odds ratio [OR], 6.97; 95% CI, 2.87-16.93; P < .001), presence of at least 1 disease complication (stricture, fistula, abscess) at baseline bowel US (OR, 3.90; 95% CI, 1.21-12.53; P = .021), fecal calprotectin value of 250 μg/g or greater at baseline (OR, 5.43; 95% CI, 2.25-13.11; P < .001), and male sex (OR, 2.60; 95% CI, 1.12-6.02; P = .025).

CONCLUSIONS

Bowel US predicts the 12-month course in CD.

Ultrasonography in inflammatory bowel disease - So far we are?

Intestinal ultrasound (IUS) is a non‐invasive and accurate tool to assess inflammatory bowel disease. The ECCO‐ESGAR guideline recommends the use of IUS for the assessment of disease activity and complications in Crohn's disease (CD). In addition, an increasing body of evidence suggests the use of IUS as alternative to colonoscopy in monitoring CD and in assessing disease activity of ulcerative colitis. Early responsiveness of IUS findings by the first weeks of treatment and the advantage to perform the procedure in real time may dramatically change frequency of the assessment of treatment response in the future and speed up the clinical decision‐making process. Development of validated and reproducible sonographic scores to measure disease activity and therapeutic response and spread of knowledge of IUS remain relevant issues for the future in which current researchers and the International Bowel Ultrasound (IBUS) Group are actively engaged.

Bowel ultrasound score is accurate in assessing response to therapy in patients with Crohn's disease

BACKGROUND

We developed a non-invasive bowel ultrasound score (BUSS) to assess disease activity in Crohn's disease (CD). BUSS >3.52 is an indicator of endoscopic activity (SES-CD>2).

AIM

To assess whether BUSS, in addition to detecting inflammatory lesions, also detects relevant changes of these lesions over time.

METHODS

This was a prospective observational study of 49 patients with active CD. All patients underwent bowel ultrasound and colonoscopy at baseline and at re-assessment after treatment with biologics and/or immunosuppressants. The primary objective was to assess the sensitivity to change of BUSS in patients treated for active CD, using the SES-CD as reference standard.

RESULTS

BUSS changed significantly from baseline to re-assessment in patients achieving endoscopic response (a reduction of SES-CD of at least 50% vs baseline: 4.87 [3.78-6.0] vs 2.47 [2.25-3.36], P < 0.001) and endoscopic remission (SES-CD ≤ 2: 4.65 [3.58-6.03] vs 2.25 [2.25-3.46], P = 0.003). A change of -1.2 in BUSS over time predicted endoscopic response (AUC 0.786, 95% CI 0.645-0.890; sensitivity 74%, specificity 83%). BUSS determined endoscopic response with 80% accuracy, and endoscopic remission with 78% accuracy. BUSS accurately detected changes in lesion severity (Guyatt score: 1.41 and standardized effect score: 1.74). BUSS did not change significantly in patients who did not achieve endoscopic response (5.62 [5.26-6.15] vs 5.70 [4.97-6.19], P = 0.53) or endoscopic remission (5.62 [5.18-6.14] vs 5.10 [4.58-6.05]; P = 0.10).

CONCLUSION

BUSS is sensitive to change in CD.

Ultrasound use to assess Crohn's disease in the UK: a survey of British Society of Gastroenterology Inflammatory Bowel Disease Group members

BACKGROUND

Small bowel ultrasound has very good diagnostic accuracy for disease extent, presence and activity in Crohn's Disease, is well tolerated by patients and is cheaper when compared with MRI. However, uptake of ultrasound in the UK is limited.

METHODS

An online survey to assess the current usage of ultrasound throughout the UK was undertaken by BSG IBD group members between 9/06/2021- 25/06/2021. Responses were anonymous.

RESULTS

103 responses were included in the data analysis. Responses came from 66 different NHS trusts from 14 different regions of the UK. All respondents reported that they currently have an MRI service for Crohn's disease, whereas only 31 had an ultrasound service. Average time for results to be reported for MRI scans was reported as between 4- and 6 weeks, with a range of 2 days to 28 weeks. The average time for an ultrasound to be reported was stated as 1-4 weeks, with a range of 0-8 weeks. There was disparity between the reported confidence of clinicians making clinical decisions when using ultrasound compared to MRI. Of those respondents who did not have access to an ultrasound service, 72 stated that they would be interested in developing an ultrasound service.

CONCLUSION

There is an appetite for the uptake of ultrasound in the UK for assessment of Crohn's disease, however, there remains a significant number of UK centres with little or no access to an ultrasound service. Further research is necessary to understand why this is the case.

Treatment Targets in Ulcerative Colitis: Is It Time for All In, including Histology?

The main therapeutic goal of ulcerative colitis (UC) is to induce and maintain remission to prevent long-term disease progression. Treat-to-target strategies, first introduced by the STRIDE consensus and updated in 2021, have shifted focus from symptomatic control toward more stringent objective endpoints. Today, patient monitoring should be based on a combination of biomarkers and clinical scores, while patient-reported outcomes could be used as short-term targets in monitoring disease activity and therapeutic response. In addition, endoscopic healing was the preferred long-term goal in UC. A Mayo endoscopic score (MES) ≤ 1 can be recommended as a minimum target. However, recent evidence suggests that more stringent endoscopic goals (MES of 0) are associated with superior outcomes. Recently, emerging data support that histological remission (HR) is a superior prognostic factor to endoscopic healing in predicting long-term remission. Despite not yet being recommended as a target, HR may become an important potential therapeutic goal in UC. However, it remains questionable if histological healing should be used as a routine assessment in addition to clinical, biomarker, and endoscopic targets in all patients. Therefore, in this review, our aim was to discuss the current evidence for the different treatment targets and their value in everyday clinical practice.

Research-Based Product Innovation to Address Critical Unmet Needs of Patients with Inflammatory Bowel Diseases

Despite progress in recent decades, patients with inflammatory bowel diseases face many critical unmet needs, demonstrating the limitations of available treatment options. Addressing these unmet needs will require interventions targeting multiple aspects of inflammatory bowel disease pathology, including disease drivers that are not targeted by available therapies. The vast majority of late-stage investigational therapies also focus primarily on a narrow range of fundamental mechanisms. Thus, there is a pressing need to advance to clinical stage differentiated investigational therapies directly targeting a broader range of key mechanistic drivers of inflammatory bowel diseases. In addition, innovations are critically needed to enable treatments to be tailored to the specific underlying abnormal biological pathways of patients; interventions with improved safety profiles; biomarkers to develop prognostic, predictive, and monitoring tests; novel devices for nonpharmacological approaches such as minimally invasive monitoring; and digital health technologies. To address these needs, the Crohn's & Colitis Foundation launched IBD Ventures, a venture philanthropy-funding mechanism, and IBD Innovate®, an innovative, product-focused scientific conference. This special IBD Innovate® supplement is a collection of articles reflecting the diverse and exciting research and development that is currently ongoing in the inflammatory bowel disease field to deliver innovative and differentiated products addressing critical unmet needs of patients. Here, we highlight the pipeline of new product opportunities currently advancing at the preclinical and early clinical development stages. We categorize and describe novel and differentiated potential product opportunities based on their potential to address the following critical unmet patient needs: (1) biomarkers for prognosis of disease course and prediction/monitoring of treatment response; (2) restoration of eubiosis; (3) restoration of barrier function and mucosal healing; (4) more effective and safer anti-inflammatories; (5) neuromodulatory and behavioral therapies; (6) management of disease complications; and (7) targeted drug delivery.

Point-of-care Intestinal Ultrasound in IBD Patients: Disease Management and Diagnostic Yield in a Real-world Cohort and Proposal of a Point-of-care Algorithm

INTRODUCTION

Intestinal ultrasound [IUS] is useful for assessment of inflammation, complications, and treatment follow-up in inflammatory bowel disease [IBD] patients. We aimed to study outcomes and impact on disease management for point-of-care [POC] IUS in IBD patients.

METHODS

Two patient cohorts undergoing POC IUS [January 2016-July 2018 and October 2019-December 2019] were included retrospectively. Disease management after IUS was analysed and IUS outcomes were compared with symptoms, biomarkers, and additional imaging within 8 weeks from IUS. To study differences in use of IUS over time, cohorts were compared.

RESULTS

In total, 345 examinations (280 in Crohn's disease [CD]/65 in ulcerative colitis [UC]) were performed. Present inflammation on IUS was comparable between symptomatic and asymptomatic CD [67.6% vs 60.5%; p = 0.291]. In 60%, IUS had impact on disease management with change in medication in 47.8%. Additional endoscopy/magnetic resonance imaging [MRI] was planned after 32.8% examinations, showing good correlation with IUS in 86.3% [ρ = 0.70, p <0.0001] and 80.0% [ρ = 0.75, p <0.0001] of cases, respectively. Faecal calprotectin was higher in active versus inactive disease on IUS [664 µg/g vs 79 µg/g; p <0.001]. Over the years, IUS was performed more frequently to monitor treatment response and the use of MRI was reduced within the cohort.

CONCLUSIONS

POC IUS affects clinical decision making and could detect preclinical relapse in CD patients, with potential to reduce additional endoscopy or MRI. In addition, the paradigm expands towards monitoring treatment and close follow-up for IUS. Based on our results, we propose a POC IUS algorithm for follow-up of IBD patients.

Bowel Ultrasound in Inflammatory Bowel Disease: How Far in the Grayscale?

Bowel ultrasound (BUS) is a non-invasive and accurate technique for assessing activity, extension of disease, and complications in inflammatory bowel diseases. The main advantages of BUS are its safety, reproducibility, and low costs. Ancillary technologies of BUS (i.e., color Doppler and wave elastography) could broaden the diagnostic power of BUS, allowing one to distinguish between inflammation and fibrosis. Considering the costs and invasiveness of colonoscopy and magnetic resonance, BUS appears as a fast, safe, and accurate technique. The objective measures of disease allow one to make clinical decisions, such as optimization, switch, or swap of therapy. Previous studies reported a sensitivity and a specificity of more than 90% compared to endoscopy and magnetic resonance. Lastly, transperineal ultrasound (TPUS) is a promising approach for the evaluation of perianal disease in Crohn’s disease (CD) and disease activity in patients with ulcerative proctitis or pouchitis. Bowel ultrasound is being incorporated in the algorithm of managing inflammatory bowel diseases. Transmural healing evaluated through ultrasonography is emerging as a complementary target for disease treatment. In this review, we aimed to summarize and discuss the current evidence on BUS in the management of inflammatory bowel diseases and to address the challenges of a full validation of this technique.

Role of Intestinal Ultrasound in the Management of Patients with Inflammatory Bowel Disease

Intestinal ultrasound (IUS) has gained popularity as a first line technique for the diagnosis and monitoring of patients with inflammatory bowel diseases (IBD) due to its many advantages. It is a non-invasive imaging technique with non-ionizing radiation exposure. It can be easily performed not only by radiologists but also by trained gastroenterologists at outpatient clinics. In addition, the cost of IUS equipment is low when compared with other imaging techniques. IUS is an accurate technique to detect inflammatory lesions and complications in the bowel in patients with suspected or already known Crohn’s disease (CD). Recent evidence indicates that IUS is a convenient and accurate technique to assess extension and activity in the colon in patients with ulcerative colitis (UC), and can be a non-invasive alternative to endoscopy. In patients with IBD, several non-specific pathological ultrasonographic signs can be identified: bowel wall thickening, alteration of the bowel wall echo-pattern, loss of bowel stratification, increased vascularization, decreased bowel peristalsis, fibro-fatty proliferation, enlarged lymph nodes, and/or abdominal free fluid. Considering the transmural CD inflammation, CD complications such as presence of strictures, fistulae, or abscesses can be detected. In patients with UC, where inflammation is limited to mucosa, luminal inflammatory ultrasonographic changes are similar to those of CD. As the technique is related to the operator’s experience, adequate IUS training, performance in daily practice, and a generalized use of standardized parameters will help to increase its reproducibility.

Clinical utility of small bowel ultrasound assessment of Crohn's disease in adults: a systematic scoping review

BACKGROUND

Ultrasound (US) is an alternative to magnetic resonance enterography, and has the potential to significantly reduce waiting times, expedite clinical decision-making and improve patient experience. Point of care US is an advantage of the US imaging modality, where same day scanning, interpretation and treatment decisions can be made.

AIM

To systematically scope the literature on point of care US use in small bowel Crohn's disease, generating a comprehensive list of factors relating to the current understanding of clinical utility of this imaging modality.

METHODS

Searches included MEDLINE, EMBASE, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, clinicaltrial.gov,'TRIP' and Epistemonikos. Reference lists of included studies were hand searched. Search terms were searched for as both keywords and subject headings (MeSH) as appropriate. Searches were performed with the 'suggested search terms' and 'explode' selection, and restricted to 'human', 'adult' and 'English language' publications. No date limits were applied to be as inclusive as possible. Two investigators conducted abstract and full-text review. No formal quality appraisal process was undertaken; however, quality of sources was considered when reporting findings. A narrative synthesis was conducted.

RESULTS

The review included 42 sources from the UK, Europe, Japan, Canada and the USA. Small bowel ultrasound (SBUS) has been shown to be as accurate in detecting the presence of small bowel Crohn's disease, is quicker, safer and more acceptable to patients, compared with magnetic resonance enterography. SBUS is used widely in central Europe and Canada but has not been embraced in the UK. Further research considering economic evaluation, clinical decision-making and exploration of perceived barriers to future implementation of SBUSs is required.

Relevance of monitoring transmural disease activity in patients with Crohn's disease: current status and future perspectives

Treatment targets of inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn's disease (CD) have evolved over the last decade. Goals of therapy consisting of symptom control and steroid sparing have shifted to control of disease activity with endoscopic remission being an important endpoint. Unfortunately, this requires ileocolonoscopy, an invasive procedure. Biomarkers [C-reactive protein (CRP) and fecal calprotectin (FCP)] have emerged as surrogates for endoscopic remission and disease activity, but also have limitations. Despite this evolution, we must not lose sight that CD involves transmural inflammation, not fully appreciated with ileocolonoscopy. Therefore, transmural assessment of disease activity by cross-sectional imaging, in particular with magnetic resonance enterography (MRE) and intestinal ultrasonography (IUS), is vital to fully understand disease control. Bowel-wall thickness (BWT) is the cornerstone in assessment of transmural inflammation and BWT normalization, with or without bloodflow normalization, the key element demonstrating resolution of transmural inflammation, namely transmural healing (TH) or transmural remission (TR). In small studies, achievement of TR has been associated with improved long-term clinical outcomes, including reduced hospitalization, surgery, escalation of treatment, and a decrease in clinical relapse over endoscopic remission alone. This review will focus on the existing literature investigating the concept of TR or residual transmural disease and its relation to other existing treatment targets. Current data suggest that TR may be the next logical step in the evolution of treatment targets.