Non-Invasive Assessment of Inflammation and Treatment Response in Patients with Crohn's Disease and Ulcerative Colitis using Contrast-Enhanced Ultrasonography Quantification

Assessment of activity and severity of inflammatory bowel disease in cross-sectional imaging techniques: a systematic review

BACKGROUND AND AIMS

Cross-sectional imaging techniques, including intestinal ultrasonography (IUS), computed tomography enterography (CTE), magnetic resonance enterography (MRE), are increasingly used for the evaluation of inflammatory bowel diseases (IBD). We aimed to systematically review literature evidence on the assessment of disease activity, and/or severity through cross-sectional imaging in IBD patients, and to offer guidance on their most effective utilization.

METHODS

We performed a systematic review of PubMed, EMBASE, and Scopus to identify citations pertaining to the assessment of disease activity and/or severity at cross-sectional imaging techniques compared to a reference standard (ie, other radiological techniques, endoscopy, histopathology, and surgery) in IBD patients published until December 2023.

RESULTS

Overall, 179 papers published between 1990 and 2023 were included, with a total of 10 988 IBD patients (9304 Crohn's disease [84.7%], 1206 ulcerative colitis [11.0%], 38 IBD-U [0.3%], 440 unspecified [4.0%]). Of the 179 studies, 39 investigated IUS, 22/179 CTE, and 101/179 MRE. In the remaining papers, 2 techniques were addressed together. In 81.6% of the papers, endoscopy (with or without histopathology) was used as a reference standard. All studies included evaluated disease activity, while just over half (100/179, 55.8%) also evaluated disease severity of the addressed cross-sectional methodology. Pooled sensitivity, specificity, and overall accuracy of IUS, MRE, and CTE compared to the reference standard were 60%-99%, 60%-100%, and 70%-99%, respectively.

CONCLUSIONS

All cross-sectional imaging techniques demonstrated moderate-to-good accuracy in assessing disease activity and severity of IBD. This finding highlights the potential, especially for MRE and IUS to be widely utilized in managing IBD in both clinical practice and clinical trials.

Systematic review on definitions of intestinal ultrasound treatment response and remission in inflammatory bowel disease

BACKGROUND

Intestinal ultrasound (IUS) is emerging as a valuable tool to assess treatment response in inflammatory bowel disease (IBD) clinical trials. This study details how IUS defines response and remission to evaluate treatment efficacy in IBD patients.

METHODS

We conducted a comprehensive search of studies from 1984 to March 31, 2024, focusing on IUS use in assessing treatment efficacy in IBD.

RESULTS

A total of 51 studies were included: 31 on Crohn's disease (CD), 12 on ulcerative colitis (UC) and 8 on IBD. Ileocolonoscopy was used as a reference standard in 53% of studies. IUS-defined response was reported in 47% of studies, with the majority (71%) using changes in bowel wall thickness (BWT) and color Doppler signals (CDS) as key indicators. IUS-defined remission was reported in 53% of studies, primarily using normalization of BWT to <3 mm and CDS to grades 0 or 1 as criteria. Ultrasonographic activity scores were used in 16% of studies, including the Bowel Ultrasound Score (BUSS) in two CD studies, the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) in one CD study, and the Milan Ultrasound Criteria (MUC) in one UC study The remaining four studies used unvalidated scores without clear definitions of response or remission. Assessment times varied, most commonly at weeks 8-16, and at 6, 12, and 24 months.

CONCLUSIONS

This systematic review reveals significant variability in IUS definitions of response and remission in IBD, highlighting the need to standardize eligibility criteria and outcome measures for IUS in IBD clinical trials.

EFSUMB Technical Review - Update 2023: Dynamic Contrast-Enhanced Ultrasound (DCE-CEUS) for the Quantification of Tumor Perfusion

Dynamic contrast-enhanced ultrasound (DCE-US) is a technique to quantify tissue perfusion based on phase-specific enhancement after the injection of microbubble contrast agents for diagnostic ultrasound. The guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) published in 2004 and updated in 2008, 2011, and 2020 focused on the use of contrast-enhanced ultrasound (CEUS), including essential technical requirements, training, investigational procedures and steps, guidance regarding image interpretation, established and recommended clinical indications, and safety considerations. However, the quantification of phase-specific enhancement patterns acquired with ultrasound contrast agents (UCAs) is not discussed here. The purpose of this EFSUMB Technical Review is to further establish a basis for the standardization of DCE-US focusing on treatment monitoring in oncology. It provides some recommendations and descriptions as to how to quantify dynamic ultrasound contrast enhancement, and technical explanations for the analysis of time-intensity curves (TICs). This update of the 2012 EFSUMB introduction to DCE-US includes clinical aspects for data collection, analysis, and interpretation that have emerged from recent studies. The current study not only aims to support future work in this research field but also to facilitate a transition to clinical routine use of DCE-US.

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.

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

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

Dynamic contrast enhanced ultrasound in gastrointestinal diseases: A current trend or an indispensable tool?

Contrast enhanced ultrasound (CEUS) has been widely implemented in clinical practice because of the enormous quantity of information it provides, along with its low cost, reproducibility, minimal invasiveness, and safety of the second-generation ultrasound contrast agents. To overcome the limitation of CEUS given by the subjective evaluation of the contrast enhancement behaviour, quantitative analysis of contrast kinetics with generation of time-intensity curves has been introduced in recent years. The quantification of perfusion parameters [named as dynamic-CEUS (D-CEUS)] has several applications in gastrointestinal neoplastic and inflammatory disorders. However, the limited availability of large studies and the heterogeneity of the technologies employed have precluded the standardisation of D-CEUS, which potentially represents a valuable tool for clinical practice in management of gastrointestinal diseases. In this article, we reviewed the evidence exploring the application of D-CEUS in gastrointestinal diseases, with a special focus on liver, pancreas, and inflammatory bowel diseases.

Ulcerative colitis (K51), adults

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The Use of Transabdominal Ultrasound in Inflammatory Bowel Disease

Transabdominal ultrasound (TAUS) is useful in all aspects of lesion screening, monitoring activity, or treating/diagnosing any related complications of inflammatory bowel disease. Its ability to screen or diagnose complications is almost the same as that of other methods, such as CT or MRI. Moreover, its noninvasiveness makes it a first-line examination method. A TAUS image depicting ulcerative colitis will show large intestinal wall thickening that is continuous from the rectum, which is mainly due to mucosal layer thickening, while for Crohn’s disease, a TAUS image is characterized by a diversity in the areas affected, distribution, and layer structure. Indicators of activity monitoring include wall thickness, wall structure, and vascular tests that use Doppler ultrasound or contrast agents. While all of these have been reported to be useful, at this time, no single parameter has been established as superior to others; therefore, a comprehensive evaluation of these parameters is justified. In addition, evaluating the elasticity of lesions using elastography is particularly useful for distinguishing between fibrous and inflammatory stenoses. However, the lack of objectivity is the biggest drawback of using ultrasound. Standardizing and popularizing the ultrasound process will be necessary, including scanning methods, equipment settings, and image analysis.

Current noninvasive modalities in Crohn's disease monitoring

Crohn’s disease (CD) is characterized by a remitting and relapsing course. Longstanding active CD may result in accumulating intestinal damage and disease-related complications. In contrast, mucosal healing is associated with significant improvement in the health-related quality of life, longer periods of disease remission and lower risk of disease progression, complications, hospitalizations, intestinal surgeries, as well as a lower risk of developing colorectal cancer. Mucosal healing, the new treatment endpoint in CD, made necessary the development of noninvasive, accurate, objective and reliable tools for the evaluation of CD activity. Ileocolonoscopy with biopsies remains the reference standard method for the evaluation of the colonic and terminal ileal mucosa. However, it is an invasive procedure with a low risk of complications, allowing the investigation of only a small part of the small bowel mucosa without being able to assess transmural inflammation. These disadvantages limit its role in the frequent follow up of CD patients. In this review, we present the currently available biomarkers and imaging modalities for the noninvasive assessment of CD activity.

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

BACKGROUND AND AIMS

No consensus exists on defining intestinal ultrasound response, transmural healing, or transmural remission in inflammatory bowel disease, nor clear guidance for optimal timing of assessment during treatment. This systematic review and expert consensus study aimed to define such recommendations, along with key parameters included in response reporting.

METHODS

Electronic databases were searched from inception to July 26, 2021, using pre-defined terms. Studies were eligible if at least two intestinal ultrasound [IUS] assessments at different time points during treatment were reported, along with an appropriate reference standard. The QUADAS-2 tool was used to examine study-level risk of bias. An international panel of experts [n = 18] rated an initial 196 statements [RAND/UCLA process, scale 1-9]. Two videoconferences were conducted, resulting in additional ratings of 149 and 13 statements, respectively.

RESULTS

Out of 5826 records, 31 full-text articles, 16 abstracts, and one research letter were included; 83% [40/48] of included studies showed a low concern of applicability, and 96% [46/48] had a high risk of bias. A consensus was reached on 41 statements, with clear definitions of IUS treatment response, transmural healing, transmural remission, timing of assessment, and general considerations when using intestinal ultrasound in inflammatory bowel disease.

CONCLUSIONS

Response criteria and time points of response assessment varied between studies, complicating direct comparison of parameter changes and their relation to treatment outcomes. To ensure a unified approach in routine care and clinical trials, we provide recommendations and definitions for key parameters for intestinal ultrasound response, to incorporate into future prospective studies.

Contrast-enhanced ultrasonography in dogs with inflammatory bowel disease

Background

Contrast‐enhanced ultrasonography (CEUS) is used to evaluate vascularity of the gastrointestinal wall in neoplastic and inflammatory diseases.

Objective

To assess the feasibility of CEUS for the evaluation of duodenal perfusion in dogs with inflammatory bowel disease (IBD).

Animals

Forty‐two dogs with IBD and 20 clinically healthy dogs.

Methods

All CEUS studies of the duodenum were analyzed to obtain time‐intensity curves and perfusion parameters. The procedure was repeated in 12 IBD dogs 2 months after a standardized treatment.

Results

On CEUS, the duodenal wall showed a typical perfusion pattern characterized by a radial and simultaneous enhancement of the wall in all dogs. On qualitative assessment, no differences were observed in contrast medium distribution between healthy and affected dogs, or between dogs with IBD before and after treatment. Peak intensity (PI) and area under the curve (AUC) significantly differed between healthy (PI = 3.58 arbitrary units [au; 1.86‐4.93 au] and AUC = 47.63 au seconds [aus, 22.68‐62.15]) and affected dogs (PI = 5.10 au [0.63‐15.16 au] and AUC = 63.62 aus [5.31‐212.20 aus]; P = .03 and .03, respectively). No significant differences were found for the perfusion parameters before and after treatment.

Conclusions and Clinical Importance

We showed that CEUS allows discrimination between IBD affected dogs and healthy dogs by evaluation of time‐intensity curves, but did not provide useful information for monitoring therapeutic response. The qualitative assessment identified no significant differences between healthy and affected dogs, or between dogs before and after treatment.

In vivo visualization and characterization of inflamed intestinal wall: the exploration of targeted microbubbles in assessing NF-κB expression

NF‐κB, a critical cytokine of inflammatory bowel diseases (IBD), is a viable marker to reflect the inflammatory activity of the intestine. We aimed to develop NF‐κB‐targeted microbubbles (MBs) and perform molecular contrast‐enhanced ultrasound (CEUS) to quantify NF‐κB expressions on the intestinal wall in IBD mice in vivo. In this study, NF‐κB‐targeted MBs were fabricated by connecting biotin‐loaded NF‐κB antibodies and avidin‐loaded MBs. NF‐κB‐targeted MBs presented as transparent and round bubbles with an average diameter of 1.03/μm±0.01. The specific binding of targeted MBs and inflammatory cells was validated by in vitro experiments, including flow cytometry, Western blot and immunofluorescence, which revealed the specific binding of targeted MBs and inflammatory cells. Subsequently, NF‐κB‐targeted CEUS imaging was performed on mice with chemical‐induced colitis, and the peak intensity (PI) and time‐to‐peak (TTP) were quantified. Pathological and immunohistochemical (IHC) examinations were further implemented. For the target CEUS group, fast enhancement followed by slow subsiding was observed. The PI of target CEUS of the IBD mice was significantly higher than that of non‐target CEUS of the IBD mice, healthy controls and target CEUS of the treated IBD mice (34835%[13379–73492%] VS 437%[236–901%], 130%[79–231%], 528%[274–779%], p<0.0001), in accordance with the IHC results of NF‐κB expressions. The TTP of target CEUS of the treated mice was significantly higher than that of untreated mice (35.7s [18.1–49.5s] VS 8.3s [4.2–12.5s], p<0.0001). Therefore, we suggested that NF‐κB‐targeted CEUS could accurately detect and quantify NF‐κB expressions on the intestinal walls of IBD, enabling the evaluation of intestinal inflammation.

Bowel contrast-enhanced ultrasound perfusion imaging in the evaluation of Crohn's disease patients undergoing anti-TNFα therapy

AIM

To evaluate whether changes in bowel perfusion parameters measured by dynamic-CEUS (D-CEUS) can be used for monitoring response to therapy in active Crohn disease (CD).

METHODS

Fifty-four CD patients were evaluated with d-CEUS before (T0) and after 2 (T1), 6 (T2) and 12 weeks (T3) of anti-TNFα therapy. Variations from baseline were calculated for: peak intensity, PI; area under the curve, AUC; slope of wash in, Pw; time to peak, TP; mean transit time, MTT (median percentage values) and were correlated with combined endoscopic/clinical response after 12 weeks and clinical relapse within 6 months.

RESULTS

70% of patients achieved combined endoscopic/clinical response (responders). The reduction in PI, AUC, Pw and MTT between T1 and T0 was higher in responders. Relapsers (21%) showed significantly lower reduction in delta PI and Pw at T1 and T2. At T3 they showed a new increase in PI and lower reduction in delta Pw. In relapsers, AUC showed a significantly lower decrease at T2 and T3, TP showed a significant reduction at T3 and MTT showed a progressive increase at the different time-points, reaching the statistical significance at T3.

CONCLUSIONS

d-CEUS might become a reliable predictor of combined endoscopic/clinical response and clinical relapse in CD.

Ultrasound imaging for assessing functions of the GI tract

OBJECTIVE

In the following review we outline how ultrasound can be used to measure physiological processes in the gastrointestinal tract.

APPROACH

We have investigated the potential of ultrasound in assessing gastrointestinal physiology including original research regarding both basic methodology and clinical applications.

MAIN RESULTS

Our main findings show the use of ultrasound to study esophageal motility, measure volume and contractility of the stomach, assess motility, wall thickness, and perfusion of the small bowel, and evaluate wall vascularization and diameters of the large bowel.

SIGNIFICANCE

Ultrasound is a widely accessible technology that can be used for both scientific and clinical purposes. Being radiation-free and user friendly, the examination can be frequently repeated enabling longitudinal studies. Furthermore, it does not influence normal GI physiology, thus being useful to estimate motility and subtle changes in physiology. Accordingly, ultrasound scanning and physiological measurements may make a big difference for the scientist and the doctor; and for the patients who receive an efficient work-up.

Potential application of dynamic contrast enhanced ultrasound in predicting microvascular invasion of hepatocellular carcinoma

OBJECTIVE

To investigate the clinical value of dynamic contrast enhanced ultrasound (D-CEUS) in predicting the microvascular invasion (MVI) of hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

In this retrospective study, 16 patients with surgery and histopathologically proved HCC lesions were included. Patients were classified according to the presence of MVI: MVI positive group (n = 6) and MVI negative group (n = 10). Contrast enhanced ultrasound (CEUS) examinations were performed within a week before surgery. Dynamic analysis was performed by VueBox® software (Bracco, Italy). Three regions of interests (ROIs) were set in the center of HCC lesions, at the margin of HCC lesions and in the surrounding liver parenchyma accordingly. Time intensity curves (TICs) were generated and quantitative perfusion parameters including WiR (wash-in rate), WoR (wash-out rate), WiAUC (wash-in area under the curve), WoAUC (wash-out area under the curve) and WiPi (wash-in perfusion index) were obtained and analyzed.

RESULTS

All of HCC lesions showed arterial hyperenhancement (100 %) and at the late phase as hypoenhancement (75%) in CEUS. Among all CEUS quantitative parameters, the WiAUC and WoAUC were higher in MVI positive group than in MVI negative group in the center HCC lesions (P < 0.05), WiAUC, WoAUC and WiPI were higher in MVI positive group than in MVI negative group at the margin of HCC lesions. WiR and WoR were significant higher in MVI positive group.

CONCLUSIONS

D-CEUS with quantitative perfusion analysis has potential clinical value in predicting the existence of MVI in HCC lesions.

The use of contrast-enhanced ultrasound for chronic inflammatory bowel disease

Intestinal ultrasound is a non-invasive, inexpensive, accessible imaging technique that is appropriate for the study of patients with inflammatory bowel disease (IBD). It provides an assessment of inflammatory activity and complications with a diagnostic accuracy similar to that of magnetic resonance imaging (MRI) and computed tomography (CT). Furthermore, it has proven to be of great value for the follow-up and monitoring of these patients. The addition of contrast enhancement has improved the diagnostic ability of intestinal ultrasound in the assessment of both inflammatory activity and complications. The development of dynamic studies able to quantify contrast arrival and determine a number of parameters in time-intensity curves (TICs) has increased the capability of intestinal ultrasound to identify inflammation and predict response to biologic therapy.

Application of ultrasound in the diagnosis of gastrointestinal tumors

Gastrointestinal tumors are common tumors in the digestive system. Early diagnosis of gastrointestinal tumors is the key to improve prognosis and curative effect of patients with tumors. Compared with other methods of examination and diagnosis, ultrasound examination has the advantages of simple operation, non-invasive, economical, and repeatable operation. With the advancement of ultrasound technology and the development of ultrasound contrast agents, ultrasound examination is more and more applied to gastrointestinal examination. Ultrasound cannot only observe the gastrointestinal wall, but also evaluate the surrounding lesions and metastases, as well as preoperative analysis and postoperative follow-up of gastrointestinal tumors. We reviewed the diagnostic applications of ultrasound in gastrointestinal tumors.

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.

Associations between quantitative evaluation of bowel wall microvascular flow by contrast-enhanced ultrasound and indices of disease activity in Crohn's disease patients using both bolus and infusion techniques

PURPOSE

The aim is to investigate whether baseline contrast-enhanced ultrasound (CEUS) correlates with indices of activity in Crohn's disease (CD) and can predict response to medical treatment.

METHODS

In this prospective study, symptomatic CD patients underwent baseline CEUS performed with Definity using both bolus and infusion methods. Time-intensity curves (TIC), peak intensity (PI), and area under curve (AUC) from a region of interest over the diseased bowel were calculated for both bolus and infusion acquisitions. We used Mann-Whitney U test for continuous and chi-square/two-tailed Fisher's exact test for categorical variable comparison and Spearman's correlation coefficient to correlate clinical score and CEUS kinetic parameters.

RESULTS

Twenty-one patients (9 men, 12 women, median age 32 years) were accrued. Fifteen patients had clinically active disease defined as Harvey-Bradshaw Index (HBI) score ≥5. Median values of baseline CEUS parameters PI (bolus: 26 vs 8.86; P = .023 and perfusion: 7.6 vs 3.2; P = .009) and AUC (bolus: 769 vs 248.8; P = .036 and perfusion: 188.9 vs 73.9; P = .012) differed significantly in patients with active vs inactive disease. Nine patients with active disease underwent escalated or new treatment. Five were nonresponders. Responders had higher median values of baseline parameters (PI, bolus: 35 vs 18.8; P = .556, and perfusion: 7.6 vs 3.9; P = 190), (AUC, bolus: 1473.9 vs 314; P = .111, and perfusion: 154.7 vs 74.4, P = .286).

CONCLUSIONS

CEUS kinetic parameters correlate with clinical and laboratory indices and are significantly higher in patients with active disease. The responders had higher CEUS kinetic parameters than nonresponders that did not reach statistical significance in our small cohort.

The Role of the Radiologist in Determining Disease Severity in Inflammatory Bowel Diseases

Crohn's disease and ulcerative colitis are chronic inflammatory diseases that lead to progressive bowel damage including the development of stricturing and penetrating complications. Increasingly, cross-sectional imaging with computed tomography or magnetic resonance scans have emerged as leading tools to: (1) assess disease activity; (2) monitor response to therapy or disease recurrence; and (3) identify disease-related complications. Several validated radiological scoring systems have been developed to quantify cross-sectional and longitudinal inflammatory burden in these diseases and to monitor response to treatment. Bowel ultrasound is also a simple and inexpensive tool but is operator dependent in its performance.

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.

Abdominal ultrasonography with color Doppler analysis in the assessment of ileal Crohn's disease: comparison with magnetic resonance enterography

BACKGROUND/AIMS

Consistently defining disease activity remains a critical challenge in the follow-up of patients with Crohn's disease (CD). We investigated the potential applicability of abdominal ultrasonography with color Doppler (USCD) analysis for the detection of morphological alterations and inflammatory activity in CD.

METHODS

Forty-three patients with CD ileitis/ileocolitis were evaluated using USCD analysis with measurements obtained on the terminal ileum and right colon. Sonographic parameters included wall thickening, stricture, hyperemia, presence of intra-abdominal mass, and fistulas. Patients were evaluated for the clinical activity (Harvey-Bradshaw Index [HBI]), fecal calprotectin (FC) and C-reactive protein (CRP). The USCD performance was assessed using magnetic resonance enterography (MRE) as a criterion standard.

RESULTS

Most measurements obtained with USCD matched the data generated with MRE; however, the agreement improved in clinically active patients where sensitivity, positive predictive value, and accuracy were >80%, considering wall thickening and hyperemia. Complications such as intestinal wall thickening, stricture formation, and hyperemia, were detected in the USCD analysis with moderate agreement with MRE. The best agreement with the USCD analysis was obtained in regard to FC, where the sensitivity, positive predictive value, and accuracy were >70%. The overall performance of USCD was superior to that of HBI, FC and CRP levels, particularly when considering thickening, stricture, and hyperemia parameters.

CONCLUSIONS

USCD represents a practical noninvasive and low-cost tool for evaluating patients with ileal or ileocolonic disease, particularly in clinically active CD. Therefore, USCD might become a useful asset in the follow-up of patients with CD.

Quantitative contrast-enhanced ultrasound for monitoring vedolizumab therapy in inflammatory bowel disease patients: a pilot study

Background Microvascularization of the bowel wall can be visualized and quantified non-invasively by software-assisted analysis of derived time-intensity curves. Purpose To perform software-based quantification of bowel wall perfusion using quantitative contrast-enhanced ultrasound (CEUS) according to clinical response in patients with inflammatory bowel disease treated with vedolizumab. Material and Methods In a prospective study, in 18 out of 34 patients, high-frequency ultrasound of bowel wall thickness using color Doppler flow combined with CEUS was performed at baseline and after 14 weeks of treatment with vedolizumab. Clinical activity scores at week 14 were used to differentiate between responders and non-responders. CEUS parameters were calculated by software analysis of the video loops. Results Nine of 18 patients (11 with Crohn's disease and seven with ulcerative colitis) showed response to treatment with vedolizumab. Overall, the responder group showed a significant decrease in the semi-quantitative color Doppler vascularization score. Amplitude-derived CEUS parameters of mural microvascularization such as peak enhancement or wash-in rate decreased in responders, in contrast with non-responders. Time-derived parameters remained stable or increased during treatment in all patients. Conclusion Analysis of bowel microvascularization by CEUS shows statistically significant changes in the wash-in-rate related to response of vedolizumab therapy.

Usefulness of contrast-enhanced ultrasound (CEUS) in Inflammatory Bowel Disease (IBD)

Intestinal ultrasonography has emerged as a cheap, non-invasive and readily accessible modality for the assessment of a number of gastroenterological diseases. Over the last decade, particularly due to the widespread use of biological agents in Inflammatory Bowel Disease (IBD), guidelines regarding management and follow-up advise more regular disease assessment and surveillance in order to guide treatment adjustments, and provide more personalised care. Given the young age of the majority of patients with IBD the availability of an alternative modality to harmful radiation or the risks of endoscopy for this indication offers an appealing advantage. Intestinal ultrasonography has been shown to be as sensitive and specific for detecting IBD as both computed tomography and magnetic resonance enterography, and endoscopic evaluation. More recent developments in the technology of ultrasonography equipment and the use of intravenous contrast agents (contrast enhanced ultrasonography, known as CEUS), have significantly increased the ability to both detect disease location, determine the disease activity and also potentially the difference between fibrotic and inflammatory segments. This review focusses specifically on the value of CEUS for the diagnosis of both Crohn's disease and Ulcerative Colitis, in determining disease activity, extraintestinal complications, determination of fibrosis as well as its more recent use in assessing and predicting response to biological and immunosuppressive therapies.

Role of contrast-enhanced ultrasound in evaluation of the bowel

Contrast-enhanced ultrasound (CEUS) of the gastrointestinal tract provides vascular information helpful for characterizing masses and other pathologies in and around the bowel, similar to contrast applications in other solid organs. However, the use of microbubble contrast agents for the bowel provides additional unique contributions as it gives both subjective and objective information about mural and mesenteric blood flow, invaluable for the determination of disease activity in those many patients affected by inflammatory bowel disease (IBD). IBD is a lifelong chronic disease and has its peak age of onset in adolescence or young adult life. Today, we have moved away from treating patient’s symptoms and strive instead to alter the course of disease by obtaining mucosal healing. Expensive and aggressive biologic therapies and lack of agreement of patient’s symptoms with their disease activity and complications necessitate frequent imaging surveillance, which must be safe, readily available, inexpensive, and effective. Ultrasound with the benefit of contrast enhancement meets these requirements and is shown in meta-analysis to be equivalent to CT and MRI scans for these indications.

Reliability of EUS indices to detect inflammation in ulcerative colitis

BACKGROUND AND AIMS

EUS is a potentially useful modality to assess severity of inflammation in ulcerative colitis (UC). We assessed the reliability of existing EUS indices and correlated them with endoscopic and histologic scores.

METHODS

Four blinded endosonographers assessed 58 endoscopic and EUS videos in triplicate, from patients with UC. Intrarater and interrater reliability of the hyperemia and Tsuga scores were estimated by using intra-class correlation coefficients (ICCs). Correlation with the Mayo endoscopy score, modified Baron score (MBS), Ulcerative Colitis Endoscopic Index of Severity (UCEIS), and Geboes histopathology score (GHS) were calculated by using bootstrapping methods. A RAND consensus process led to development of standardized definitions and a revised EUS-UC score.

RESULTS

ICCs for intrarater reliability were 0.76 (95% confidence interval [CI], 0.71-0.80) for the hyperemia score and 0.85 (95% CI, 0.79-0.89) for the Tsuga score. Corresponding values for interrater reliability were 0.34 (95% CI, 0.25-0.42) and 0.36 (95% CI, 0.24-0.46). Correlation between hyperemia and Tsuga scores to Mayo scoring system, MBS, UCEIS, and the GHS were 0.39 (95% CI, 0.15-0.61) and 0.28 (95% CI, 0.04-0.51), 0.38 (95% CI, 0.16-0.57) and 0.25 (95% CI, -0.01-0.48), 0.41 (95% CI, 0.16-0.62) and 0.27 (95% CI, 0.01-0.50), 0.37 (95% CI, -0.01-0.48) and 0.24 (95% CI, 0.13-0.57), respectively. The revised EUS-UC score included bowel wall thickening, depth of inflammation, and hyperemia.

CONCLUSIONS

Although substantial to almost perfect intrarater agreement existed for EUS indices in UC, interrater agreement was fair. Standardization of item definitions with development of a revised evaluative instrument has potential application as an evaluative and prognostic tool for UC. (Clinical trial registration number: NCT01852760.).

Peptide Receptor-Targeted Fluorescent Probe: Visualization and Discrimination between Chronic and Acute Ulcerative Colitis

The inflammatory activity of ulcerative colitis plays an important role in the medical treatment. However, accurate and real-time monitoring of the colitis activity with noninvasive bioimaging method is still challenging, especially in distinguishing between chronic and acute colitis. As a good receptor, the oligopeptide transporter (PepT1) is overexpressed in the colonic epithelial cells of chronic ulcerative colitis, which can deliver tripeptide KPV (Lys-Pro-Val, the C-terminal sequence of α-MSH) into cytosol in the intestine. Herein, we report a PepT1 peptide receptor-targeted fluorescent probe, dicyanomethylene-4H-pyran (DCM)-KPV, with the strategy of conjugating the KPV into the DCM chromophore. The diagnostic fluorescent probe bestows a specific receptor-targeted interaction with PepT1 through the KPV moiety, possessing several beneficial characteristics, such as efficient long emission, low photobleaching, negligible cytotoxicity, and high cytocompatibility in living cells. We build the overexpressed PepT1 on the cytomembrane of ulcerative colitis model Caco-2 cell as the efficient receptor to accumulate the targeted tripeptide KPV in the cytoplasm and nucleus. With the co-localization of DCM-KPV and the DNA-specific fluorophore, DAPI, the specifically long emission from chromophore DCM and efficient receptor-targeted peptide KPV, the fluorescent probe of DCM-KPV makes a breakthrough to the direct noninvasive observation of the accumulation in colon inflammation regions via intestinal mucosa, even successfully distinguishing the chronic, acute ulcerative colitis and normal groups. Compared with the traditional unenhanced magnetic resonance imaging and hematoxylin and eosin (H&E) staining, we make full use of exploiting the specific target-receptor interaction between the tripeptide unit, KPV, and the oligopeptide transporter, PepT1, for sensing selectivity. The desirable diagnostic ability of DCM-KPV can guarantee the real-time tracking and visualization of the role of intracellular KPV on ulcerative colitis, which provides an alternative to replace the time-consuming and tissue sampling-invasive H&E staining diagnosis.

Dynamic Contrast-Enhanced Magnetic Resonance Enterography and Dynamic Contrast-Enhanced Ultrasonography in Crohn's Disease: An Observational Comparison Study

Purpose e Cross-sectional imaging methods are important for objective evaluationof small intestinal inflammationinCrohn'sdisease(CD).The primary aim was to compare relative parameters of intestinal perfusion between contrast-enhanced ultrasonography (CEUS) and dynamic contrast-enhanced magnetic resonance enterography (DCE-MRE) in CD. Furthermore, we aimed at testing the repeatability of regions of interest (ROIs) for CEUS. Methods This prospective study included 25 patients: 12 females (age: 37, range: 19-66) with moderate to severe CD and a bowel wall thickness>3mm evaluated with DCE-MRE and CEUS. CEUS bolus injection was performed twice for repeatability and analyzed in VueBox®. Correlations between modalities were described with Spearman's rho, limits of agreement(LoA) and intraclass correlation coefficient(ICC). ROIrepeatability for CEUS was assessed. Results s The correlation between modalities was good and very good for bowel wall thickness (ICC=0.71, P<0.001) and length of the inflamed segment (ICC=0.89, P<0.001). Moderate-weak correlations were found for the time-intensity curve parameters: peak intensity (r=0.59, P=0.006), maximum wash-in-rate (r=0.62, P=0.004), and wash-in perfusion index (r=0.47, P=0.036). Best CEUS repeatability for peak enhancement was a mean difference of 0.73 dB (95% CI: 0.17 to 1.28, P=0.01) and 95% LoA from -3.8 to 5.3 dB. Good quality of curve fit improved LoA to -2.3 to 2.8 dB. Conclusion The relative perfusion of small intestinal CD assessed with DCE-MRE and CEUS shows only a moderate correlation. Applying strict criteria for ROIs is important and allows for good CEUS repeatability.