Clinical relevance of transabdominal ultrasonography and magnetic resonance imaging in patients with inflammatory bowel disease of the terminal ileum and large bowel

Bismuth drug-inspired ultra-small dextran coated bismuth oxide nanoparticles for targeted computed tomography imaging of inflammatory bowel disease

Bismuth (Bi)-based computed tomography (CT) imaging contrast agents (CAs) hold significant promise for diagnosing gastrointestinal diseases due to their cost-effectiveness, heightened sensitivity, and commendable biocompatibility. Nevertheless, substantial challenges persist in achieving an easy synthesis process, remarkable water solubility, and effective targeting ability for the potential clinical transformation of Bi-based CAs. Herein, we show Bi drug-inspired ultra-small dextran coated bismuth oxide nanoparticles (Bi2O3-Dex NPs) for targeted CT imaging of inflammatory bowel disease (IBD). Bi2O3-Dex NPs are synthesized through a simple alkaline precipitation reaction using bismuth salts and dextran as the template. The Bi2O3-Dex NPs exhibit ultra-small size (3.4 nm), exceptional water solubility (over 200 mg mL-1), high Bi content (19.75 %), excellent biocompatibility and demonstrate higher X-ray attenuation capacity compared to clinical iohexol. Bi2O3-Dex NPs not only enable clear visualization of the GI tract outline and intestinal loop structures in CT imaging but also specifically target and accumulate at the inflammatory site in colitis mice after oral administration, facilitating a precise diagnosis and enabling targeted CT imaging of IBD. Our study introduces a novel and clinically promising strategy for synthesizing high-performance Bi2O3-Dex NPs for diagnosing gastrointestinal diseases.

Clinical Application of Intestinal Ultrasound in Inflammatory Bowel Disease

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

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

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

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.

Evaluation of intestinal ultrasound for disease activity assessment in patients with inflammatory bowel disease: A cross-sectional study at a tertiary centre in Malaysia

Background

The use of intestinal ultrasound (IUS) in the management of inflammatory bowel disease (IBD) is emerging. We aim to determine the performance of IUS in the assessment of disease activity in IBD.

Methods

This is a prospective cross-sectional study of IUS performed on IBD patients in a tertiary centre. IUS parameters including intestinal wall thickness, loss of wall stratification, mesenteric fibrofatty proliferation, and increased vascularity were compared with endoscopic and clinical activity indices.

Results

Among the 51 patients, 58.8% were male, with a mean age of 41 years. Fifty-seven percent had underlying ulcerative colitis with mean disease duration of 8.4 years. Against ileocolonoscopy, IUS had a sensitivity of 67% (95% confidence interval (CI): 41-86) for detecting endoscopically active disease. It had high specificity of 97% (95% CI: 82-99) with positive and negative predictive values of 92% and 84%, respectively. Against clinical activity index, IUS had a sensitivity of 70% (95% CI: 35-92) and specificity of 85% (95% CI: 70-94) for detecting moderate to severe disease. Among individual IUS parameters, presence of bowel wall thickening (>3 mm) had the highest sensitivity (72%) for detecting endoscopically active disease. For per-bowel segment analysis, IUS (bowel wall thickening) was able to achieve 100% sensitivity and 95% specificity when examining the transverse colon.

Conclusions

IUS has moderate sensitivity with excellent specificity in detecting active disease in IBD. IUS is most sensitive in detecting a disease at transverse colon. IUS can be employed as an adjunct in the assessment of IBD.

External validation and comparison of simple ultrasound activity score and international bowel ultrasound segmental activity score for Crohn's disease

BACKGROUND

Intestinal ultrasound (IUS) is a non-invasive tool for monitoring Crohn's disease (CD) activity. Recently, sonographic activity scores, including the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) and Simple Ultrasound Activity Score for CD (SUS-CD), were developed. This study aimed to assess their clinical application value.

METHODS

This retrospective study enrolled patients with CD from March 2021 to June 2022. The diagnostic performance of the ultrasound scores was evaluated using the simplified endoscopic score for CD (SES-CD). Correlations of ultrasound scores with SES-CD, CD activity index (CDAI), and inflammatory biomarkers were assessed. Inter-rater reliability was compared.

RESULTS

In total, 140 patients were included. The IBUS-SAS for evaluating disease activity had an area under the curve (AUC) of 0.895, sensitivity of 85.4%, and specificity of 82.4% for the cut-off value of 48.7. The SUS-CD revealed an AUC of 0.835, sensitivity of 92.7%, and specificity of 64.7% for the cut-off value of 2.5. The IBUS-SAS and SUS-CD were positively correlated with SES-CD (r = 0.511 and 0.534, respectively). The scores correlated significantly with the CDAI and inflammatory biomarkers (all p < 0.01). The IBUS-SAS was more strongly correlated with CDAI (r = 0.666 vs 0.486) and C-reactive protein (r = 0.645 vs 0.434) than the SUS-CD. The intraclass correlation coefficient (ICC) of the IBUS-SAS and SUS-CD between the two sonologists was excellent (ICC = 0.96 and 0.78, respectively).

CONCLUSION

Both the IBUS-SAS and SUS-CD can evaluate disease activity in CD and exhibited a significant correlation with activity indices and inflammatory biomarkers.

CLINICAL TRIAL REGISTRATION

ChiCTR2200055221.

Diagnostic accuracy of different cross-sectional imaging techniques for disease location and activity in Crohn's disease and external validation and comparison of MARIAs and IBUS-SAS

PURPOSE

The comparative accuracy of cross-sectional imaging techniques for evaluating Crohn's disease (CD) remains uncertain. This study aimed to assess diagnostic accuracy of disease location and activity in different cross-sectional images and validate and compare International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) and Simplified Magnetic Resonance Index of Activity (MARIAs).

METHODS

CD patients were retrospectively included from August 2018 to May 2021. We compared accuracy of B-mode intestinal ultrasound (B-IUS), computed tomography enterography (CTE), and magnetic resonance enterography (MRE) for the identification of disease location. Meanwhile, disease activity was compared on B-IUS, color Doppler imaging, CTE, and MRE. ROC analyses were used to validate MARIAs and IBUS-SAS. Spearman rank correlation was performed to evaluate the relationships between MARIAs/IBUS-SAS and CDAI, SES-CD, and inflammatory indicators.

RESULTS

A total of 115 CD patients were evaluated. The diagnostic accuracy of MRE in detecting small bowel disease was superior to that of B-IUS/CTE, showing sensitivity (89.3%), specificity (71.4%), and AUC (0.820). B-IUS had the highest sensitivity (81.2%), specificity (84.8%), and AUC (0.830) for detecting terminal ileal lesions. The diagnostic accuracy for colonic disease and disease activity was not significantly different among these techniques. In the validation of IBUS-SAS, the AUC was 0.860, with an optimal cutoff value to predict active disease of 46.7. MARIAs and IBUS-SAS showed no significant differences in the correlations of CDAI, SES-CD, and inflammatory indicators.

CONCLUSION

MRE and B-IUS are more sensitive for detecting small bowel CD and terminal ileal CD, respectively. IBUS-SAS has potential for precisely defining CD activity.

Intestinal Ultrasound in the Assessment of Luminal Crohn’s Disease

Crohn’s disease is a chronic inflammatory disease affecting the gastrointestinal tract. Expert guidelines now recommend regular objective assessments as part of a treat-to-target approach. Intestinal ultrasound provides a noninvasive, patient-friendly modality for assessing Crohn’s disease without the risk of radiation exposure and does not require fasting or bowel preparation. Enhancement techniques, including oral and intravenous contrast, can improve disease-activity and complication detection. Due to its acceptability, intestinal ultrasound can be performed frequently, allowing for closer disease-activity monitoring and treatment adjustments. There have been significant advances in the utility of intestinal ultrasound; particularly for assessing disease activity during pregnancy and fibrosis detection utilising elastography. This review provides a comprehensive overview of performing intestinal ultrasound, the diagnostic accuracy, role in disease-activity monitoring, and recent advances in utilising ultrasound for the assessment of luminal Crohn’s disease.

The Colon Wall Thickness Measured Using Transabdominal Ultrasonography Is Useful for Detecting Mucosal Inflammation in Ulcerative Colitis

Objective Transabdominal ultrasonography (TUS) is a non-invasive procedure that is reportedly useful for managing ulcerative colitis (UC) and assessing bowel wall thickness (BWT), the most common measure of mucosal inflammation. However, the exact range of BWT that reflects disease activity remains undetermined. The present study clarified the BWT due to disease activity by comparing the use of TUS in each segment of the colon versus using colonoscopy (CS) and determined the usefulness of TUS in patients with UC. Methods We divided the colon into five segments and measured the BWT using TUS. The results were then compared to the Mayo endoscopic subscore (MES) classification to determine the accuracy of BWT measurement. Patients Eighty patients with UC who underwent TUS within 14 days of CS were retrospectively registered. Results We evaluated a total of 268 images depicting each segment among 80 patients with UC. The BWT was positively correlated with endoscopic activity (0.69, p<0.0001). In each segment, the relationship between a BWT>2 mm and an MES>0 had the highest sensitivity, specificity, and accuracy (0.85-1.00, 0.67-0.92, and 0.81-0.97, respectively). Conclusion This study concluded that TUS was a useful method of detecting an MES>0, which indicates the presence of inflammation and its location among UC patients. MES>0 was found to be highly accurate when a BWT>2 mm was considered positive. This non-invasive method may help control disease activity in patients with UC.

Comparison of Diagnostic Performance of Ultrasonography and Magnetic Resonance Enterography in the Assessment of Active Bowel Lesions in Patients with Crohn’s Disease: A Systematic Review and Meta-Analysis

We aimed to evaluate and compare the diagnostic performances of ultrasonography (US) and magnetic resonance enterography (MRE) in assessing active bowel lesions in patients with Crohn’s disease (CD). Materials and Methods: We searched PubMed and EMBASE for studies in which US and MRE were used to assess active bowel lesions in CD patients. Bivariate random effect meta-analytic methods were used to estimate pooled sensitivity, specificity, and hierarchical summary receiver operating characteristic (HSROC) curves. We performed a meta-regression analysis to explore the source of study heterogeneity. Results: Eleven studies involving 752 patients were included. US exhibited a pooled sensitivity of 86% (95% confidence interval (CI) 72–94), pooled specificity of 88% (95% CI 78–94), and HSROC of 0.93 in 10 studies. MRE exhibited a pooled sensitivity of 88% (95% CI 76–95), pooled specificity of 87% (95% CI 73–95), and an HSROC of 0.94 in eight studies. In seven studies comparing the diagnostic performances of US and MRE, the summary sensitivity of US and MRE were 86% (95% CI 65–96, I² = 92.1) and 86% (95% CI 72–93, I² = 88.1) (p = 0.841), respectively. The summary specificity of US and MRE were 87% (95% CI 78–93, I² = 79.8%) and 84% (72–90, I² = 72.5%) (p = 0.431), respectively, which showed no statistical differences. On meta-regression analysis, studies from Europe (p = 0.002), those that used linear US probes (p = 0.012), those on small bowel lesions (p = 0.01), and those with outcomes as combined features (active inflammation) reported higher US sensitivity than those from other regions, those that used both linear and convex US probes, those on small and large bowels, and those with outcome as one feature (bowel wall thickening or ulcer). Studies with pediatric patients (p = 0.001), those with reference standards including US (p = 0.001), and outcomes as combined features (p = 0.01) reported higher MRE specificity than those with adult populations, reference standards other than the US, and outcomes as one feature. Conclusions: In spite of considerable heterogeneity in the included studies, both US and MRE can diagnose active bowel lesions with comparable diagnostic accuracy in patients with CD. The study region, type of US probe, lesion location, investigated outcome for US sensitivity and study population, reference standards, and investigated outcomes for MRE specificity were potential sources of heterogeneity.

Early sonographic response to a new medical therapy is associated with future treatment response or failure in patients with inflammatory bowel disease

OBJECTIVE

Gastrointestinal ultrasound (GIUS) accurately assesses inflammation and is responsive to changes in inflammatory bowel disease. This study aimed to determine the prognostic utility of sonographic response in the first 14 weeks of a newly-instituted therapy with therapeutic response at 46 weeks and to compare its performance with standard clinical assessment tools.

METHODS

Patients with sonographic evidence of inflammation were assessed by GIUS, clinical activity, serum C-reactive protein and faecal calprotectin again 2, 6 and 14 weeks after commencing a new biologic or thiopurine. Treatment failure was defined as undergoing surgery, hospitalisation, escalation of dosage or introduction of new medication over 46-weeks' follow-up. Sonographic response was defined as a decrease in bowel wall thickness and improved vascularity.

RESULTS

In 31 patients (median age 49 years, 74% Crohn's disease), sonographic response at 14 weeks [OR 19.3, 95% confidence interval (CI), 3.23-101.10; P = 0.0054] and faecal calprotectin (P = 0.018), but no clinical disease activity or C-reactive protein, were predictive of subsequent treatment response. Sonographic response alone was predictive at week 6 (P = 0.016), but not week 2. 16% reduction in bowel wall thickness at 6 weeks (area-under-the-receiver-operator-curve=0.86; P = 0.002; sensitivity 72%, specificity 90%), with similar performance for 10% at 14 weeks, was associated with treatment response.

CONCLUSION

Sonographic response as early as 6 weeks after initiation of a new therapy may accurately predict treatment outcomes over 46 weeks and is superior to other markers used to monitor disease activity.

Nonspecific ileitis: Impact of histopathology and gastrointestinal ultrasound in achieving the diagnosis of Crohn's disease

Background and Aim

Nonspecific ileitis is inflammation of the ileum without specific diagnostic features. A minority may go on to develop Crohn's disease, but optimal pathways of further investigation have not been established. This study aimed to identify a cohort of patients with nonspecific ileitis and to determine the value of ileal histology and gastrointestinal ultrasound in identifying/excluding Crohn's disease.

Patients and Methods

In a retrospective analysis, all patients having nonspecific ileitis at colonoscopy from January 2010 to August 2021 were identified. Clinical associations with those subsequently diagnosed with Crohn's disease were examined with specific reference to ileal histology and gastrointestinal ultrasound.

Results

Of 29 638 procedures, 147 patients (0.5%) had nonspecific ileitis. Crohn's disease was subsequently diagnosed in 8 patients (5.4%) at a median of 148 (range 27–603) days after colonoscopy. The presence of chronic inflammation on ileal biopsies was more common in those subsequently diagnosed with Crohn's disease (63% vs 20%; P = 0.0145). On gastrointestinal ultrasound, none of the 26 patients with normal bowel wall thickness (<3 mm) were subsequently diagnosed with Crohn's disease, and repeat ultrasound in 15 patients 1 year later showed no change. Of the nine patients with abnormal sonographic findings, three were diagnostic for Crohn's disease. Repeat ultrasound revealed Crohn's disease in two, while four had resolution of the abnormal findings.

Conclusion

Although ileal histology was of limited value in identifying patients with nonspecific ileitis who were subsequently diagnosed with Crohn's disease, gastrointestinal ultrasound was highly informative. Prospective studies are needed to confirm the value of gastrointestinal ultrasound as a diagnostic and monitoring tool in this setting.

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.

Intestinal Ultrasonography as a Tool for Monitoring Disease Activity in Patients with Ulcerative Colitis

BACKGROUND

Ultrasonography is a noninvasive, inexpensive, and widely available diagnostic tool. In the last two decades, the development of ultrasound techniques and equipment has significantly increased the usage of intestine ultrasound (US) in the assessment of the gastrointestinal tract in patients with inflammatory bowel disease (IBD). Although current guidelines suggest routine utilization of US in patients with Crohn's disease, data regarding US usage in ulcerative colitis are still scarce. We aimed to assess the reliability of intestinal ultrasonography in the assessment of disease activity and extension of patients with ulcerative colitis.

METHODS

Fifty-five patients with a histologically confirmed diagnosis of ulcerative colitis, treated at University Clinical Center of Serbia in the period from 2019 to 2022 were included in this retrospective observational study. The data were obtained from the patient's medical records including history, laboratory, US, and endoscopy findings. US examined parameters were as following: bowel wall thickness (BWT), presence of fat wrapping, wall layer stratification, mesenteric hypertrophy, presence of enlarged mesenteric lymph nodes, and absence or presence of ascites.

RESULTS

Our results suggest that there is a strong correlation of BWT and colonoscopy findings regarding disease extension (r = 0.524, p=0.01, p < 0.05). Furthermore, our results have shown a statistically significant correlation of BWT with the Mayo endoscopic score (r = 0.434, p=0.01, p < 0.05), disease activity score (r = 0.369,p=0.01, p < 0.05), degree of ulcerative colitis burden of luminal inflammation (r = 0.366, p=0.01, p < 0.05), and Geboes index (r = 0.298, p=0.027, p < 0.05). Overall accuracy of US for disease extension and activity was statistically significant (p < 0.05).

CONCLUSIONS

Our results suggest that US is a moderately accurate method for the assessment of disease activity and localization in patients with UC.

Crohn's Disease Activity Evaluation by Transabdominal Ultrasonography: Correlation with Double-Balloon Endoscopy

OBJECTIVES

Transabdominal ultrasonography (US) has been reported as a useful tool for evaluating Crohn's disease (CD) activity. Endoscopic findings and Crohn's disease activity index (CDAI) are currently considered the gold standard for assessing CD activity. We assessed the correlation between US and double-balloon endoscopy (DBE), and CDAI for evaluating CD activity.

METHODS

We analyzed patients with CD undergoing US and DBE within 10 days between the procedures. The intestine was divided into four segments and analyzed by the US scoring system (US-CD) and the simple endoscopic score for Crohn's disease (SES-CD). CDAI was compared with US-CD and SES-CD. Spearman's rank correlation coefficient was used for statistical analysis.

RESULTS

Twenty-five patients with CD (11 women, 14 men; mean age 35.4 ± 14.9 years, range 16-65 years) were enrolled. Twenty-four patients received antitumor necrosis factor inhibitor therapy. CDAI was 128.1 (range 36-227). A significant moderate correlation was found between the US-CD and SES-CD in all segments (ρ = .64, P < .01). The US-CD showed a strong correlation with CDAI (ρ = .78, P < .01), whereas the SES-CD showed a moderate correlation (ρ = .55, P < .05).

CONCLUSIONS

US-CD and SES-CD showed a moderate correlation for assessing CD activity. US-CD showed a stronger correlation with CDAI than SES-CD, suggesting that US could more accurately evaluate the disease activity.

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

Background

Intestinal ultrasound is emerging as a non-invasive tool for monitoring disease activity in inflammatory bowel disease patients due to its low cost, excellent safety profile, and availability. Herein, we comprehensively review the role of intestinal ultrasound in the management of these patients.

Summary

Intestinal ultrasound has a good accuracy in the diagnosis of Crohn's disease, as well as in the assessment of disease activity, extent, and evaluating disease-related complications, namely strictures, fistulae, and abscesses. Even though not fully validated, several scores have been developed to assess disease activity using ultrasound. Importantly, intestinal ultrasound can also be used to assess response to treatment. Changes in ultrasonographic parameters are observed as early as 4 weeks after treatment initiation and persist during short- and long-term follow-up. Additionally, Crohn's disease patients with no ultrasound improvement seem to be at a higher risk of therapy intensification, need for steroids, hospitalisation, or even surgery. Similarly to Crohn's disease, intestinal ultrasound has a good performance in the diagnosis, activity, and disease extent assessment in ulcerative colitis patients. In fact, in patients with severe acute colitis, higher bowel wall thickness at admission is associated with the need for salvage therapy and the absence of a significant decrease in this parameter may predict the need for colectomy. Short-term data also evidence the role of intestinal ultrasound in evaluating therapy response, with ultrasound changes observed after 2 weeks of treatment and significant improvement after 12 weeks of follow-up in ulcerative colitis.

Key Messages

Intestinal ultrasound is a valuable tool to assess disease activity and complications, and to monitor response to therapy. Even though longer prospective data are warranted, intestinal ultrasound may lead to a change in the paradigm of inflammatory bowel disease management as it can be used in a point-of-care setting, enabling earlier intervention if needed.

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.

Diagnostic Accuracy of Non-Invasive Imaging for Detection of Colonic Inflammation in Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

Endoscopy is the gold standard for objective assessment of colonic disease activity in inflammatory bowel disease (IBD). Non-invasive colonic imaging using bowel ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) may have a role in quantifying colonic disease activity. We reviewed the diagnostic accuracy of these modalities for assessment of endoscopically or histopathologically defined colonic disease activity in IBD. We searched Embase, MEDLINE, and the Web of Science from inception to 20 September 2021. QUADAS-2 was used to evaluate the studies' quality. A meta-analysis was performed using a bivariate model approach separately for MRI and US studies only, and summary receiver operating characteristic (ROC) curves were obtained. CT studies were excluded due to the absence of diagnostic test data. Thirty-seven studies were included. The mean sensitivity and specificity for MRI studies was 0.75 and 0.91, respectively, while for US studies it was 0.82 and 0.90, respectively. The area under the ROC curves (AUC) was 0.88 (95% CI, 0.82 to 0.93) for MRI, and 0.90 (95% CI, 0.75 to 1.00) for US. Both MRI and US show high diagnostic accuracy in the assessment of colonic disease activity in IBD patients.

Intestinal Ultrasound to Assess Disease Activity in Ulcerative Colitis: Development of a novel UC-Ultrasound Index

INTRODUCTION

Intestinal ultrasound [IUS] is useful to assess inflammation in ulcerative colitis [UC] patients. We aimed to develop an ultrasonographic activity index using endoscopy as the reference standard.

METHODS

Patients were included consecutively. IUS was performed within 3 weeks from endoscopy. IUS parameters and endoscopy were compared for each colonic segment [except the rectum]. The best parameters were used to construct a UC-IUS index, which was correlated with endoscopic disease activity using the Spearman's rank test.

RESULTS

In 60 patients, 207 colonic segments were evaluated endoscopically. Bowel wall thickness [BWT] > 2.1 mm was optimal to discriminate between Mayo 0 and Mayo 1-3 (sensitivity 82.6%; specificity 93.0%; area under the curve [AUC] 0.910), a cut-off of 3.2 mm was optimal to discriminate between Mayo 0-1 and Mayo 2-3 [sensitivity 89.1%; specificity 92.3%; AUC 0.946] and BWT > 3.9 mm was optimal for detection of Mayo 3 [sensitivity 80.6%; specificity 84.1%; AUC 0.909]. The presence of colour Doppler signal [CDS] predicted active disease, stretches of CDS were associated with Mayo 2-3, lack of haustrations predicted active disease and fat wrapping was associated with severe disease. Inter- and intra-rater intraclass correlation for BWT was substantial. Inter-rater agreement for CDS was substantial and ranged from slight to substantial for haustrations. Intra-rater agreement for CDS was substantial and ranged from moderate to almost perfect for haustrations. The index showed strong correlation with endoscopic disease activity [Mayo: ρ 0.830; p < 0.001, UCEIS: ρ 0.759; p < 0.001].

CONCLUSION

We developed an UC-IUS index which showed strong correlation with endoscopic disease activity using internal validation. It is currently being validated in prospective studies.

Qualitative sonographic assessment of transmural ileal inflammation in Crohn's disease: a comparison with MRI activity score

BACKGROUND

Intestinal ultrasound (IUS) is an accurate tool for monitoring Crohn's disease. To date, there is no clinically used validated quantitative ultrasonographic score for assessing disease activity. For magnetic resonance enterography (MRE), the magnetic resonance index of activity (MaRIA) is most used. The goal of this study was to devise a new quantitative IUS score for assessing Crohn's disease inflammation, by using a partial MaRIA score as a reference.

METHODS

This was a retrospective cohort study. The study cohort included patients with Crohn's disease followed between January 2016 and December 2018. Inclusion criteria were age >18 and <3 months between MRE and IUS. Linear/logistic regression was performed for the correlation of ultrasonographic parameters with MaRIA score. Ultrasonograpic features included: bowel wall thickness, disrupted bowel wall stratification, mesenteric fat proliferation, presence of lymph nodes, hypervascularity present on color Doppler flow, and the presence of complications (strictures, inflammatory mass, and fistula).

RESULTS

Forty-two patients were included. A stepwise multiple regression model was constructed to predict MaRIA score using ultrasound features. Two variables were found to be independently significant: terminal ileum (TI) thickness (r = 0.68, P = 0.001) and mesenteric fat proliferation (r = 0.45, P = 0.019). A model was constructed as follows: MaRIA = 7 + 2.5 * TI US thickness (mm) + 7 * US fat proliferation (0 = no, 1 = yes). This model has an R2 of 0.51 for explaining the variability in the results.

CONCLUSIONS

IUS measurements are significantly correlated with MaRIA score in the terminal ileum and a simple computational model can be constructed.

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.

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

BACKGROUND & AIMS

The accuracy of ultrasound for evaluation of individual colorectal segments in patients with inflammatory bowel diseases (IBD) has not been evaluated in a systematic review. We evaluated the diagnostic accuracy of ultrasound in different colorectal segments of patients with IBD.

METHODS

We searched publication databases from inception through March 2019 for studies that assessed the accuracy of ultrasound in detection of inflammation in right, transverse, and left colon and in rectum in patients with IBD, using findings from colonoscopy as the reference standard. Subgroup analyses were performed including IBD type, patient age, body mass index, and study design. The risk of bias was assessed with the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

RESULTS

Nineteen studies (1101 patients) were included in the qualitative synthesis. After we assessed the risk of bias, 7 studies (comprising 84 patients with Crohn's disease and 420 patients with ulcerative colitis) were included in the meta-analysis. Bowel wall thickness ≥ 3 mm identified colorectal segments with inflammation with 86.4% pooled sensitivity (95% CI, 76.1%-92.7%) and 88.3% pooled specificity (95% CI, 58.1%-97.6%). In rectum only, bowel wall thickness ≥ 3 mm identified inflammation with 74.5% sensitivity (95% CI, 53.0%-88.3%) and 69.5% specificity (95% CI, 33.6%-91.1%). Diagnostic accuracy was comparable among subgroups. Increased bowel wall flow and loss of stratification had higher true-positive odds ratios.

CONCLUSIONS

Based on meta-analysis of patient-level data, ultrasound has higher diagnostic accuracy for detecting inflammation in colon than rectum in patients with IBD. Studies are needed to increase the accuracy of ultrasound detection of inflammation in rectum.

Systematic Review: Gastrointestinal Ultrasound Scoring Indices for Inflammatory Bowel Disease

BACKGROUND AND AIMS

Serial measurements of luminal disease activity may facilitate inflammatory bowel disease management. Gastrointestinal ultrasound is an easily performed, non-invasive alternative to other assessment modes. However, its widespread use is limited by concerns regarding validity, reliability, and responsiveness. We systematically identified ultrasound scoring indices used to evaluate inflammatory bowel disease activity and examine their operating characteristics.

METHODS

Electronic databases were searched from inception to June 14, 2019 using pre-defined terms. Studies that reported on gastrointestinal ultrasound index operating properties in an inflammatory bowel disease population were eligible for inclusion. Study characteristics, index components, and operating property data [ie, validity, reliability, responsiveness, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value] were extracted. The QUADAS-2 tool was used to examine study-level risk of bias.

RESULTS

Of the 2610 studies identified, 26 studies reporting on 21 ultrasound indices were included. The most common index components included bowel wall thickness, colour Doppler imaging, and bowel wall stratification. The correlation between ultrasound indices and references standards ranged r = 0.62-0.95 and k = 0.40-0.96. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive values ranged 39-100%, 63-100%, 73-100%, 57-100%, and 40-100%, respectively. Reliability and responsiveness data were limited. Most [92%, 24/26] studies received at least one unclear or high risk of bias rating.

CONCLUSIONS

Several gastrointestinal ultrasound indices for use in inflammatory bowel disease have been developed. Future research should focus on fully validating existing or novel gastrointestinal ultrasound scoring instruments for assessment of Crohn's disease and ulcerative colitis.

Point-of-Care Ultrasound in Inflammatory Bowel Disease

Inflammatory bowel diseases [IBD], including Crohn's disease [CD] and ulcerative colitis [UC], are chronic, relapsing and destructive inflammatory disorders of the gastrointestinal tract which can lead to organ damage and impair quality of life. A 'treat-to-target' strategy based on activity and severity of disease and response to treatment with close monitoring of intestinal inflammation is recommended. Ileocolonoscopy [CS] is considered the first-line procedure for the assessment of IBD, and magnetic resonance enterography [MRE] is the current standard for assessing the small bowel and complications in CD, and has been proposed as an alternative procedure to CS in the evaluation of both ileo-colonic CD and UC. As that both CS and MRE are invasive and expensive procedures and unappealing to patients, they are unfeasible as frequent and repetitive tools for the monitoring of disease activity. Bowel ultrasound [US] represents a well-tolerated, non-invasive and cost-effective modality to manage IBD patients in clinical practice. Compared to CS and MRE, bowel US has been shown to have the same level of accuracy in assessing and monitoring disease activity and severity of both CD and UC. It can be performed at the point-of-care and therefore allow for real-time clinical decision-making. Point-of-care ultrasound [POCUS] is suggested as the stethoscope of the future and is gaining interest and diffusion in the medical field because it can be used for the bedside examination of patients. The aim of this review is to discuss point-of-care bowel ultrasound [POCBUS] in the management of patients with IBD.

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.

The establishment of a regression model from four modes of ultrasound to predict the activity of Crohn's disease

To establish a multi-parametric regression model from four modes of ultrasound to predict the activity of Crohn's disease (CD) noninvasively. Score of 150 of the Crohn’s Disease Activity Index (CDAI) was taken as the cut-off value to divide the involved bowel segments of 51 patients into the active and inactive group. Eleven parameters from four modes of ultrasound (B-mode ultrasonography, color Doppler flow imaging, contrast-enhanced ultrasonography and shear wave elastography) were compared between the two groups to investigate the relationship between multimodal ultrasonic features and CD activity. P < 0.05 was considered statistically significant. Parameters with AUC larger than 0.5 was selected to establish the prediction model of CDAI. Totally seven ultrasound parameters (bowel wall thickness, mesenteric fat thickness, peristalsis, texture of enhancement, Limberg grade, bowel wall perforation and bowel wall stratification) were significantly different between active and inactive group. A regression model was established based on the seven parameters as followed: CDAI = 211.325 + 3.186BWT − 53.003BWS + 6.280BWP + 0.392MFT + 22.239PS + 79.012LG + 72.793TE. (R² = 0.72, P = 0.037). The multimodal ultrasound parametric regression model was designed to predict CDAI score invasively. The model has the potential to provide an alternative method for quantifying the CD activity.

Evaluation of Crohn's Disease Activity: Development of an Ultrasound Score in a Multicenter Study

OBJECTIVE

Our goal in this multicentric prospective study was 2-fold: first, to test the diagnostic accuracy of ultrasound, color Doppler imaging (CDI), and contrast-enhanced ultrasound (CEUS) in identifying disease activity in patients with Crohn's disease (CD) compared with endoscopy as the reference standard; and, second, to construct a sonographic score that allows disease activity to be detected.

MATERIALS AND METHODS

Seventy-two patients with CD from 3 hospitals underwent within a 30-day period both colonoscopy and ultrasound (US), including mural thickness, CDI, and CEUS, prospectively as part of clinical care. A multivariate analysis was carried out to assess the influence of each of the ultrasound variables in predicting endoscopic activity. We then developed a predictive ultrasound score for disease activity, and a receiver operating characteristic (ROC) curve was constructed to determine the area under the ROC curve (AUC) and the best cut-off score value to discriminate between active and inactive disease.

RESULTS

Sonographic findings that were independent predictors of the presence of active disease at endoscopy were wall thickness, color grade, and contrast parameters. A score based on those variables showed high accuracy in predicting active disease, with an area under the ROC curve of 0.972. A simpler index, without contrast parameters, also showed high accuracy in detecting disease activity (AUC, 0.923).

CONCLUSION

A score based on wall thickness, color Doppler grade, and contrast parameters showed high accuracy in predicting active disease. A score without including the use of contrast agent had practically similar results and is easier to use in monitoring response to treatment.

Ulcerative Colitis: Making the Diagnosis

Ulcerative colitis is an inflammatory condition of the colon. The diagnosis of ulcerative colitis is based on clinical presentation, endoscopic evaluation, and histologic parameters in the absence of demonstrable alternate etiology. The differential diagnosis remains broad, and infection in particular must be considered and excluded. Although laboratory and radiographic findings can aid in the diagnosis of ulcerative colitis, endoscopy remains the gold standard for diagnosis. A correct diagnosis and disease staging are imperative because these factors affect treatment options and prognosis.

Intestinal ultrasound for monitoring therapeutic response in patients with ulcerative colitis: results from the TRUST&UC study

OBJECTIVE

Prospective evaluation of intestinal ultrasound (IUS) for disease monitoring of patients with ulcerative colitis (UC) in routine medical practice.

DESIGN

TRansabdominal Ultrasonography of the bowel in Subjects with IBD To monitor disease activity with UC (TRUST&UC) was a prospective, observational study at 42 German inflammatory bowel disease-specialised centres representing different care levels. Patients with a diagnosis of a proctosigmoiditis, left-sided colitis or pancolitis currently in clinical relapse (defined as Short Clinical Colitis Activity Index ≥5) were enrolled consecutively. Disease activity and vascularisation within the affected bowel wall areas were assessed by duplex/Colour Doppler ultrasonography.

RESULTS

At baseline, 88.5% (n=224) of the patients had an increased bowel wall thickness (BWT) in the descending or sigmoid colon. Even within the first 2 weeks of the study, the percentage of patients with an increased BWT in the sigmoid or descending colon decreased significantly (sigmoid colon 89.3%-38.6%; descending colon 83.0%-42.9%; p<0.001 each) and remained low at week 6 and 12 (sigmoid colon 35.4% and 32.0%; descending colon 43.4% and 37.6%; p<0.001 each). Normalisation of BWT and clinical response after 12 weeks of treatment showed a high correlation (90.5% of patients with normalised BWT had symptomatic response vs 9.5% without symptomatic response; p<0.001).

CONCLUSIONS

IUS may be preferred in general practice in a point-of-care setting for monitoring the disease course and for assessing short-term treatment response. Our findings give rise to the assumption that monitoring BWT alone has the potential to predict the therapeutic response, which has to be verified in future studies.

Development and Validation of a Simple Ultrasound Activity Score for Crohn's Disease

BACKGROUND AND AIMS

To improve management of patients with Crohn's disease, objective measurements of disease activity are needed. Ileocolonoscopy is the current reference standard but has limitations that restrict repeated use. Ultrasonography is potentially useful for activity monitoring, but no validated sonographic activity index is currently in widespread use. Thus, we aimed to construct and validate a simple ultrasound score for Crohn's disease.

METHODS

Forty patients were prospectively examined with ultrasound and endoscopy in the development phase. The Simple Endoscopic Score for Crohn's Disease [SES-CD] was used as a reference standard. Seven ultrasound variables [bowel wall thickness, length, colour Doppler, stenosis, fistula, stratification and fatty wrapping] were initially included, and multiple linear regression was used to select the variables that should be included in the final score. Second, the ultrasound data from each patient were re-examined for interobserver assessment using weighted kappa and intraclass correlation. Finally, the activity index was validated in a new cohort of 124 patients.

RESULTS

Length, fistula and stenosis were excluded. The combination of the remaining variables provided a multiple correlation coefficient of r = 0.78. Interobserver analysis revealed poor agreement for stratification and fatty wrapping and these were thus excluded. There was excellent interobserver agreement for the remaining score consisting of wall thickness and colour Doppler. In both patient cohorts, the ultrasound score correlated well with SES-CD [Development cohort: rho = 0.83, p < 0.001, Validation cohort: rho = 0.78, p < 0.001]. A receiver operating characteristic curve analysis revealed an area under the curve of 0.92 and 0.88 for detecting endoscopic activity and moderate endoscopic activity, respectively.

CONCLUSIONS

A simple ultrasound activity index for Crohn's disease consisting of bowel wall thickness and colour Doppler was constructed and validated and correlated well with endoscopic disease activity.ClinicalTrials. gov ID: NCT03481751.

Transperineal ultrasound predicts endoscopic and histological healing in ulcerative colitis

BACKGROUND

Transabdominal ultrasound is useful to assess inflammation in patients with ulcerative colitis (UC); however, the assessment of the rectum is challenging and a barrier for its widespread use.

AIM

To evaluate if transperineal ultrasound is useful for predicting endoscopic and histological findings of the rectum in UC.

METHODS

Fifty-three consecutive adults with UC who required colonoscopy were included and transperineal ultrasound was performed in combination with transabdominal ultrasound within a week before or after colonoscopy with rectal biopsy. Mayo endoscopic subscore (MES) ≤1 was defined as endoscopic healing and Geboes score <2.1, Robarts histopathology index ≤6, and Nancy index ≤1 were defined as histological healing. Limberg score and bowel wall thickness were recorded with transperineal ultrasound. Faecal calprotectin was also measured.

RESULTS

Excellent correlation was confirmed between colonoscopy and transabdominal ultrasound in all segments except for the rectum. Rectal bowel wall thickness and Limberg score in transperineal ultrasound well correlated with rectal MES and histological indices. Bowel wall thickness ≤4 mm predicted endoscopic (Area under the curve [AUC] = 0.90) and histological (AUC = 0.87-0.89) healing. In multivariable logistic regression analysis, only bowel wall thickness in transperineal ultrasound was a significant independent predictor for rectal endoscopic and histologic healing (P < 0.05) and the predictability was better than faecal calprotectin.

CONCLUSIONS

Transperineal ultrasound predicts endoscopic and histological healing of the rectum. The combination of transperineal ultrasound with transabdominal ultrasound visualises the entire colorectum and is an ideal modality for the treat-to-target strategy. Clinical Trials Registry number UMIN000033611 (https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000038323).

Systematic Review: Clinical Utility of Gastrointestinal Ultrasound in the Diagnosis, Assessment and Management of Patients With Ulcerative Colitis

BACKGROUND AND AIMS

Gastrointestinal ultrasound is useful in the assessment of patients with Crohn's disease, but its application in ulcerative colitis [UC] is less well established. Here we systematically review the role of gastrointestinal ultrasound in patients with UC.

METHODS

Searches of the PUBMED and EMBASE databases were performed with the following search strategy: [ultrasound OR sonography] AND [intestinal OR bowel] AND [ulcerative colitis OR inflammatory bowel disease]. The final search was performed in August 2019.

RESULTS

Of 6769 studies identified in the search with a further two studies found from other sources, 50 studies met the inclusion criteria. Increased bowel wall thickness and detection of increased blood flow by colour Doppler were the most often applied criteria for defining disease activity and distribution. When compared with other reference investigations, gastrointestinal ultrasound accurately determined disease extent, severity and response to medical therapy. While further information can be obtained from haemodynamic measurements of the abdominal vessels and contrast-enhanced ultrasound, their clinical value was uncertain. Likewise, hydrocolonic sonography has few advantages over standard gastrointestinal ultrasound examination. Of several scoring systems proposed, there is disparity between the measures and a general lack of validation. There has been limited application of gastrointestinal ultrasound in acute severe ulcerative colitis with toxic megacolon, and, while performing well in children, normal limits differ from those in adults.

CONCLUSION

Current evidence indicates that gastrointestinal ultrasound has utility in the non-invasive assessment of patients with UC. Continued advances in technology with better image resolution, validation of scoring systems and application at the point of care by gastroenterologists are likely to contribute to increased use of gastrointestinal ultrasound in routine clinical practice.

Use of Cross-Sectional Imaging for Tight Monitoring of Inflammatory Bowel Diseases

A treat-to-target strategy with close monitoring of intestinal inflammation is recommended in inflammatory bowel disease (IBD). Ileocolonoscopy remains the gold standard for assessing disease activity in IBD but is a relatively invasive procedure and is impossible to repeat in the context of tight monitoring strategies. In addition to biomarkers, cross-sectional imaging increasingly is used in these patients. Computed tomography is limited by the use of radiation, while the use of magnetic resonance enterography (MRE) is limited by its cost and access. There is growing interest in bowel ultrasound that represents a cost-effective, noninvasive, and well-tolerated modality in clinical practice, but it is operator dependent. Compared with ileocolonoscopy and MRE, bowel US has been shown to have the same level of accuracy in assessing and monitoring disease activity for both CD and UC and thus can be considered a point-of-care test. Diffusion-weighted imaging (DWI) is a MR imaging technique that increasingly is used in both IBD and non-IBD conditions and has been shown to be a valuable and accurate tool for assessing and monitoring IBD activity. Compared with conventional MRE, DWI is quicker, less time consuming, may not require intravenous contrast agent, fasting, bowel cleansing, oral preparation, or rectal preparation. This review discusses the role of these cross-sectional imaging techniques for the management of patients with IBD. In the near future, the value of DWI and ultrasound in assessing IBD will require further investigation in the era of transmural healing in CD and complete mucosal healing, including histologic remission, in ulcerative colitis.

How Do We Treat Inflammatory Bowel Diseases to Aim For Endoscopic Remission?

Crohn's disease and ulcerative colitis are heterogeneous conditions which may manifest with 1 or more of a constellation of abnormal symptoms, elevated biomarkers, and/or objective evidence of inflammation on endoscopic or cross-sectional evaluation. Whilst resolution of symptoms and restoration of quality of life is the primary goal for patients following a disease flare, there may be discordance between resolution of symptoms, biomarkers, and endoscopy. Increased emphasis is placed on the achievement of endoscopic remission, given it is associated with improved outcomes and reduction in hospitalization and surgeries. As the therapeutic armamentarium for inflammatory bowel disease does not achieve remission in all patients, there is greater emphasis on repetitive interval-based assessment of disease activity with sequential algorithmic treatment adjustments until endoscopic remission is achieved, in a so-called treat-to-target approach. We review the role of symptoms, biomarkers, imaging and endoscopy within treat-to-target algorithms and provide a practical guidance to their use in clinical practice.

Use of magnetic resonance index of activity (MaRIA) in the preoperative assessment of small bowel Crohn's disease

BACKGROUND

Accurate quantification of the inflammatory activity in Crohn's Disease is essential to determine adequate treatment for each patient. The aim of the present study is to assess the correlation between the pre-operative Magnetic Resonance Index of Activity (MaRIA) and the histologic degree of inflammation from surgically resected intestinal Crohn's Disease lesions.

METHODS

This is a prospective study including a consecutive case series of patients with small bowel Crohn's Disease, who underwent surgical resection. Magnetic resonance enterography was performed in the 3months prior to surgery, applying a pre-established protocol. Relative contrast enhancements, wall thickness, presence of edema or ulcerations were the parameters used to calculate the MaRIA Index. All patients underwent surgery and every specimen was analyzed. The modified Chiorean classification was applied for the histological analysis and an ordinal regression analysis was used to correlate MaRIA and the grade of inflammation for each lesion.

RESULTS

59 lesions from 35 different patients were analyzed. The degree of inflammation of the lesions was statistically correlated to the MaRIA values (P=.002). The MaRIA index was significantly different (P<.001) between the different histological types of the Crohn's Disease lesions (inflammatory/ fibrotic). The best cut-off for detecting severe inflammation using MaRIA was 20 (AUC: 0.741; 74.1% sensitivity and 78.1% specificity).

CONCLUSION

MaRIA is a reliable tool to distinguish inflammatory from fibrotic lesions. Therefore, it could be considered essential for determining the most appropriate Crohn's Disease treatment for each patient.

Differentiation of Crohn's disease and ulcerative colitis using intestinal wall thickness of the colon: A Diagnostic accuracy study of endoscopic ultrasonography

Background: The differentiation between Ulcerative Colitis (UC) and Crohn's Disease (CD) is an important issue for choosing the appropriate treatment. Endoscopic Ultrasonography (EUS) has been used to distinguish different layers of the gastrointestinal wall. We performed this study to evaluate the accuracy of EUS in differentiating colonic UC from CD compared to standard tests (colonoscopy, pathology, imaging, and clinical presentation). Methods: This is a prospective, single-blinded diagnostic accuracy study, on 70 patients (30 UC, 30 CD, and 10 healthy controls). After obtaining informed consent, patients underwent a complete workup and were referred to an endosonographist who was blind to the diagnosis. The thickness of mucosa, submucosa and the total wall (TWT) of mid-sigmoid colon were measured by Pentax radial echoendoscope EPKI-7000 with Avius Hitachi ultrasound system (Japan). Statistical analyses were performed using the SPSS statistical software (v23). Statistical significance was considered if P-values were less than 0.05. Results: Our study revealed a sensitivity of 100% (90.7-100%) and specificity of 90.9% (70.8-98.8%) for EUS to differentiate UC and CD compared to standard diagnostic tests. Mean mucosal thickness in patients with UC was significantly greater than patients with CD, while, the mean sub-mucosal thickness was significantly greater in patients with CD (p<0.001). The sensitivity and specificity of mean mucosal thickness for differentiating UC from CD and controls were 92.3% and 88.6% with a cut-off point of 1.1 mm (p<0.001). Moreover, sensitivity and specificity of mean submucosal thickness for differentiating CD from UC and controls were 100% and 86.1% with a cut-off point of 1.08 mm (p<0.001). Conclusion: EUS can be used as an efficient modality with acceptable accuracy to differentiate Crohn's disease and Ulcerative Colitis and to determine disease activity.

Usefulness of transabdominal ultrasonography for assessing ulcerative colitis: a prospective, multicenter study

BACKGROUND

Transabdominal ultrasonography (US) has been reported to be a useful tool for evaluating ulcerative colitis (UC) although with less well-established data than for Crohn's disease. This prospective multicenter study aimed to establish the usefulness of US compared with colonoscopy (CS) for assessing disease extent and activity of UC.

METHODS

Altogether, 173 patients with UC were prospectively enrolled, among whom 156 were eligible for this study. All patients underwent US and CS within 2 days at five facilities. We divided the colon into six segments and examined each segment and the rectum using US and CS. US severity was graded 1-4 regarding bowel wall thickness, stratification, and ulceration. CS severity was also graded 1-4 according to Matts' endoscopic classification. Concordance between US and CS grades for all colonic segments was analyzed using kappa statistics. US and CS findings were also compared with the clinical disease activity index (CAI) and histological grade using Spearman's correlation coefficient.

RESULTS

There was moderate concordance between US and CS grades in all colonic segments (weighted κ = 0.55, p < 0.001). Concordance was rated moderate for each colonic segment but only slight for the rectum. The US grade was significantly correlated with the CAI score (r = 0.40, p < 0.001) and histological grade (r = 0.35, p < 0.001).

CONCLUSIONS

This prospective multicenter study showed moderate concordance between US and CS for assessing the disease activity of UC. Hence, US may be used more generally for evaluating UC in daily clinical practice.

Ultrasound for Assessing Disease Activity in IBD Patients: A Systematic Review of Activity Scores

BACKGROUND AND AIMS

Ultrasound [US] indices for assessing disease activity in IBD patients have never been critically reviewed. We aimed to systematically review the quality and reliability of available ultrasound [US] indices compared with reference standards for grading disease activity in IBD patients.

METHODS

Pubmed, Embase and Medline were searched for relevant literature published within the period 1990 to June 2017. Relevant publications were identified through full text review after initial screening by two investigators. Data on methodology and index characteristics were collected. Study quality was assessed using a modified version of the Quadas-2 tool for risk of bias assessment.

RESULTS

Of 20 studies with an US index, 11 studies met the inclusion criteria. Out of these 11 studies, 7 and 4 studied Crohn's disease [CD] and ulcerative colitis [UC0 activity indices, respectively. Parameters that were used in these indices included bowel wall thickness [BWT], Doppler signal [DS], wall layer stratification [WLS], compressibility, peristalsis, haustrations, fatty wrapping, contrast enhancement [CE], and strain pattern. Study quality was graded high in 5 studies, moderate in 3 studies and low in 3 studies. Ileocolonoscopy was used as the reference standard in 9 studies. In 1 study a combined index of ileocolonoscopy and barium contrast radiography and in 1 study histology was used as the reference standard. Only 5 studies used an established endoscopic index for comparison with US.

CONCLUSIONS

Several US indices for assessing disease activity in IBD are available; however, the methodology for development was suboptimal in most studies. For the development of future indices, stringent methodological design is required.

Inflammatory bowel disease and its treatment in 2018: Global and Taiwanese status updates

The global incidence and prevalence of inflammatory bowel disease (IBD) has increased over the last 2-4 decades, likely because of the adoption of a more "western" lifestyle as well as improved detection and awareness, and Taiwan is no exception. To characterize the increasing burden of IBD, we conducted a comprehensive review of IBD in the existing literature. The following parameters were reviewed: background knowledge and current standard care for IBD, including natural history, epidemiology, pathogenesis, diagnosis, monitoring, and treatment. In addition, new imaging modalities and treatment options such as combined positron emission tomography and magnetic resonance enterography, new biologic agents, small-molecule therapy, biosimilar therapeutics, mesenchymal stem cell transplantation, and fecal microbiota transplantation, all of which have been introduced for IBD management, were reviewed. We also used the hospital-based as well as population-based Taiwan National Health Insurance Research Database to assess Taiwan-specific trends for comparison with global trends.

Detecting inflammation in inflammatory bowel disease - how does ultrasound compare to magnetic resonance enterography using standardised scoring systems?

BACKGROUND

Magnetic resonance enterography (MRE) is the current gold standard for imaging in inflammatory bowel disease, but ultrasound (US) is a potential alternative.

OBJECTIVE

To determine whether US is as good as MRE for the detecting inflamed bowel, using a combined consensus score as the reference standard.

MATERIALS AND METHODS

We conducted a retrospective cohort study in children and adolescents <18 years with inflammatory bowel disease (IBD) at a tertiary and quaternary centre. We included children who underwent MRE and US within 4 weeks. We scored MRE using the London score and US using a score adapted from the METRIC (MR Enterography or Ultrasound in Crohn's Disease) trial. Four gastroenterologists assessed an independent clinical consensus score. A combined consensus score using the imaging and clinical scores was agreed upon and used as the reference standard to compare MRE with US.

RESULTS

We included 53 children. At a whole-patient level, MRE scores were 2% higher than US scores. We used Lin coefficient to assess inter-observer variability. The repeatability of MRE scores was poor (Lin 0.6). Agreement for US scoring was substantial (Lin 0.95). There was a significant positive correlation between MRE and clinical consensus scores (Spearman's rho = 0.598, P=0.0053) and US and clinical consensus scores (Spearman's rho = 0.657, P=0.0016).

CONCLUSION

US detects as much clinically significant bowel disease as MRE. It is possible that MRE overestimates the presence of disease when using a scoring system. This study demonstrates the feasibility of using a clinical consensus reference standard in paediatric IBD imaging studies.

A Simple Ultrasound Score for the Accurate Detection of Inflammatory Activity in Crohn's Disease

BACKGROUND

Ultrasound is accurate in the detection of Crohn's disease. Our aim was to identify ultrasound parameters contributing to inflammatory disease activity, develop a simple score, and validate this score prospectively.

METHODS

This study comprised 2 single-center investigations. The first was a retrospective study on a population that had received colonoscopies (as a gold-standard diagnostic) within 60 days of ultrasound. The second was a prospective study on 2 populations: patients requiring induction with adalimumab and patients on adalimumab maintenance therapy. Ultrasound and endoscopy were preformed within 14 days in both prospective groups. The endoscopy results were graded with the Simple Endoscopic Score and the Rutgeerts score and compared with 5 ultrasound parameters. We used a proportional odds model to determine which ultrasound parameters correlated significantly with the endoscopy results. We then developed a predictive ultrasound score for disease activity, plotted the receiver operating characteristic curves, and undertook prospective validation of the score.

RESULTS

We evaluated 160 patients retrospectively to compare ultrasound and colonoscopy. Two of 5 parameters were found to correlate significantly with disease activity: bowel wall thickness (P = <0.0001) and color Doppler signal (P = 0.0292). We developed a score that uses weighted variables. The area under the corresponding receiver operating characteristic curve was 0.8658.

CONCLUSIONS

A simple ultrasonographic score that accurately identifies Crohn's disease activity has been developed and validated. Ultrasound may be a surrogate for endoscopy to guide disease management, but future studies should be conducted to establish interrater variability.

Advances in Use of Endoscopy, Radiology, and Biomarkers to Monitor Inflammatory Bowel Diseases

Crohn's disease and ulcerative colitis are heterogeneous inflammatory bowel diseases, and therapeutic requirements vary among patients. We have a limited capacity to predict disease progression for individual patients, therefore it is important that they are evaluated for the presence of active disease when symptoms are mild or even absent, when patients are more likely to respond to new treatment interventions. It then is important to monitor responses to treatment, to quickly identify those therapies that are ineffective, modify or change therapy, and avoid disease complications. Studies are underway to assess the effects of different monitoring strategies. Because of the heavy burden of severe inflammatory bowel disease on patients' health and quality of life, and the association between intestinal healing and disease progression in high-risk patients, a treat-to-target strategy (based on tissue healing) is likely to be optimal.

Utility of MR enterography and ultrasound for the investigation of small bowel Crohn's disease

Cross sectional Imaging plays an increasingly important role the diagnosis and management of Crohn's disease. Particular emphasis is placed on MRI and Ultrasound as they do not impart ionising radiation. Both modalities have reported high sensitivity for disease detection, activity assessment and evaluation of extra-luminal complications, and have positive effects on clinical decision making. International Guidelines now recommend MRI and Ultrasound in the routine management of Crohn's disease patients. This article reviews the current evidence base supporting both modalities with an emphasis on the key clinical questions. We describe current protocols, basic imaging findings and highlight areas in need of further research.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 4 J. MAGN. RESON. IMAGING 2017;45:1573-1588.

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

OBJECTIVE

The primary objective of our study was to examine the association between contrast-enhanced ultrasound (CEUS) parameters and established gray-scale ultrasound with color Doppler imaging (CDI) for the determination of disease activity in patients with Crohn disease. Our secondary objective was to develop quantitative time-signal intensity curve thresholds for disease activity.

MATERIALS AND METHODS

One hundred twenty-seven patients with Crohn disease underwent ultrasound with CDI and CEUS. Reviewers graded wall thickness, inflammatory fat, and mural blood flow as showing remission or inflammation (mild, moderate, or severe). If both gray-scale ultrasound and CDI predicted equal levels of disease activity, the studies were considered concordant. If ultrasound images suggested active disease not supported by CDI findings, the ultrasound results for disease activity were indeterminate. Time-signal intensity curves from CEUS were acquired with calculation of peak enhancement (PE), and AUCs. Interobserver variation and associations between PE and ultrasound parameters were examined. Multiclass ROC analysis was used to develop CEUS thresholds for activity.

RESULTS

Ninety-six (76%) studies were concordant, 19 of which showed severe disease, and 31 (24%) studies were indeterminate. Kappa analyses revealed good interobserver agreement on grades for CDI (κ = 0.76) and ultrasound (κ = 0.80) assessments. PE values on CEUS and wall thickness showed good association with the Spearman rank correlation coefficient for the entire population (ρ = 0.62, p < 0.01) and for the concordant group (ρ = 0.70, p < 0.01). Multiclass ROC analyses of the concordant group using wall thickness alone as the reference standard showed cutoff points of 18.2 dB for differentiating mild versus moderate activity (sensitivity, 89.0% and specificity, 87.0%) and 23.0 dB for differentiating moderate versus severe (sensitivity, 90% and specificity, 86.8%). Almost identical cutoff points were observed when using ultrasound global assessment as the reference standard: using 18.2 dB to differentiate mild versus moderate activity yielded sensitivity of 89.2% and specificity of 90.9% and using 22.9 dB to differentiate moderate versus severe activity yielded sensitivity of 89.5% and specificity of 83.1%.

CONCLUSION

Quantitative CEUS parameters integrated into inflammatory assessments with ultrasound reduce indeterminate results and improve disease activity level determinations.

Bowel Ultrasonography in the Management of Crohn's Disease. A Review with Recommendations of an International Panel of Experts

BACKGROUND

Bowel ultrasonography (US) is considered a useful technique for assessing mural inflammation and complications in Crohn's disease (CD). The aim of this review is to appraise the evidence on the accuracy of bowel US for CD. In addition, we aim to provide recommendations for its optimal use.

METHODS

Publications were identified by literature search from 1992 to 2014 and selected based on predefined criteria: 15 or more patients; bowel US for diagnosing CD, complications, postoperative recurrence, activity; adequate reference standards; prospective study design; data reported to allow calculation of sensitivity, specificity, agreement, or correlation values; articles published in English.

RESULTS

The search yielded 655 articles, of which 63 were found to be eligible and retrieved as full-text articles for analysis. Bowel US showed 79.7% sensitivity and 96.7% specificity for the diagnosis of suspected CD, and 89% sensitivity and 94.3% specificity for initial assessment in established patients with CD. Bowel US identified ileal CD with 92.7% sensitivity, 88.2% specificity, and colon CD with 81.8% sensitivity, 95.3% specificity, with lower accuracy for detecting proximal lesions. The oral contrast agent improves the sensitivity and specificity in determining CD lesions and in assessing sites and extent.

CONCLUSIONS

Bowel US is a tool for evaluation of CD lesions in terms of complications, postoperative recurrence, and monitoring response to medical therapy; it reliably detects postoperative recurrence and complications, as well as offers the possibility of monitoring disease progression.

Magnetic Resonance Imaging of the Small Bowel in Crohn's Disease: A Systematic Review and Meta-Analysis

Introduction. Crohn's disease is most commonly found in the terminal ileum and colonic region. Magnetic resonance has become a useful modality for assessing small bowel activity. In this study, we performed a systematic review and meta-analysis on the use of MR in detecting small bowel activity as well as extramural complications in Crohn's patients. Methods. Two independent reviewers sorted through articles until October 2, 2014. We included both studies providing raw data for pooling and studies without raw data. Sensitivity, specificity, likelihood ratios, and 95% confidence intervals were calculated for each study. Results. There were 27 included studies, of which 19 were included in the pooled analysis. Pooled analysis of the 19 studies (1020 patients) with raw data revealed a sensitivity of 0.88 (95% CI 0.86 to 0.91) and specificity was 0.88 (95% CI 0.84 to 0.91). In regard to detecting stenosis, pooled sensitivity was 0.65 (95% CI 0.53 to 0.76) and specificity was 0.93 (95% CI 0.89 to 0.96). Conclusion. MR imaging provides a reliable alternative in detecting small bowel activity in patients with Crohn's disease. Its advantages include high diagnostic accuracy and no radiation exposure while its disadvantages include high cost and limited availability.