Crohn disease: correlation of findings at contrast-enhanced US with severity at endoscopy

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

Quantitative analysis of contrast-enhanced ultrasound and superb microvascular imaging for the evaluation of disease activity in inflammatory bowel disease

OBJECTIVE

To evaluate the effectiveness of conventional US (ultrasound), SMI (superb microvascular imaging), and CEUS (contrast-enhanced ultrasound) features for the assessment of the activity of inflammatory bowel disease.

METHODS

Conventional US, CEUS and SMI features of 76 patients were retrospectively analyzed. Patients were categorized into two groups: active group (n = 57) and inactive group (n = 19), with endoscopic results as reference standard. Results in the active group and inactive group were compared using an independent t-test, Mann-Whitney U test, chi-square test, and receiver operating characteristic curve (ROC) analysis. Cut-off values were determined using ROC analysis, and sensitivity and specificity were calculated. US quantitative and TIC-based quantitative parameters were analyzed, and each patient was scored based on the parameters that are statistically significant and immediately available in the clinic to evaluate the diagnostic ability of conventional US, SMI, and CEUS features for active IBD patients.

RESULTS

Qualitative parameters such as CEUS enhancement pattern I/II, LimbergIII/IV, and lost bowel stratification were reliable indicators of active patients. Quantitative parameters such as bowel thickness and VI of mSMI were reliable indicators of active patients. Patients scored based on these statistically significant parameters with a score ≥3, were highly suspected to be active patients. For TIC-based quantitative parameters, PE, WiAUC, WoAUC, WiWoAUC, WiR, WiPI, and WoR were statistically significant in the differentiation of active IBD from inactive IBD.

CONCLUSIONS

Conventional US, SMI, and CEUS features may help in the differentiation of active IBD from inactive IBD and have potential application value in the choice of treatment options.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

DISCUSSION

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

Sonographic evaluation of a surgically created pouch

This manuscript focuses on a review of the normal and abnormal sonographic appearance of the surgically created pouch as part of an article series on the topic. It includes information regarding sonographic technique, normal anatomy, and commonly encounter diseases and complications.

Reply to comment on "Ultrasonographic scores for ileal Crohn's disease assessment: better, worse or the same as contrast‑enhanced ultrasound?

We read the comments by Nylund K et al. regarding our paper "Ultrasonographic scores for ileal Crohn's disease assessment: Better, worse or the same as contrast‑enhanced ultrasound?". Intestinal ultrasound has become one of the most valuable developments in the past decade, a non-invasive, well-tolerated exam, with an easy repeatability, and absence of sedation, ionizing radiation, or preparation. Particularly for inflammatory bowel disease, where there is a lack of agreement of patient's symptoms with disease activity, in an era where the paradigm of mucosal healing is changing to transmural healing, and with the emergence of several therapies leading to repeated imaging surveillance, it is essential to highlight the role of intestinal ultrasound. Although intestinal ultrasound is an increasingly used tool to monitor inflammatory bowel disease activity, there is no widely accepted reproducible activity index, since the methodology for the development of the scores was shown to be insufficient in most studies and none have been adequately validated (Bots et al., J Crohns Colitis 12:920-9, 2018). In our study, we showed that the contrast-enhanced ultrasound (CEUS) peak enhancement derived from the time-intensity curve (TIC) is a promising non-invasive emerging method with a good accuracy to correlate clinical and endoscopic activity in the terminal ileum, superior to intestinal ultrasound scores relying on bowel wall thickness and colour Doppler.

Intestinal MRI in Inflammatory Bowel Disease - Literature and Survey-Based Recommendations regarding Reporting by the German Radiological Society (DRG) and the German Competence Network for Inflammatory Bowel Diseases

BACKGROUND

MR-enterography/enteroclysis (MRE) is increasingly used for primary diagnosis, detection of complications, and monitoring of patients with inflammatory bowel disease (IBD). Standardization of reporting is relevant to ensure quality of the methodology and to improve communication between different faculties. The current manuscript describes the features that are required for optimized reporting of MRE in IBD.

METHODS

An expert consensus panel of radiologists and gastroenterologists conducted a systematic search of the literature. In a Delphi process, members of the German Radiological Society (DRG) and members of the Competence Network for Inflammatory Bowel Diseases voted on relevant criteria for the reporting of findings in MRE. Based on the voting results, statements were developed by the expert consensus panel.

RESULTS

Clinically relevant aspects of MRE findings have been defined to optimize reporting and to standardize terminology. Minimal requirements for standardized reporting are suggested. The statements focus on the description of disease activity as well as on complications of IBD. Attributes of intestinal inflammation are described and illustrated by exemplary images.

CONCLUSION

The current manuscript provides standardized parameters and gives practical recommendations on how to report and how to characterize MRE findings in patients with IBD.

KEY POINTS

· Systematic overview provides practice-oriented recommendations and names and evaluates the decisive criteria for reporting and interpretation of MRI in inflammatory bowel disease.. · Standardized terminology and reporting criteria for MRI in IBD improves interdisciplinary communication.. · Standardized collection and documentation of MRI findings in IBD helps to further establish the method and to improve care for IBD patients..

CITATION FORMAT

· Wessling J, Kucharzik T, Bettenworth D et al. Intestinal MRI in Inflammatory Bowel Disease - Literature and Survey-Based Recommendations regarding Reporting by the German Radiological Society (DRG) and the German Competence Network for Inflammatory Bowel Diseases. Fortschr Röntgenstr 2023; 195: 675 - 690.

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

PURPOSE

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

PROCEDURES

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

RESULTS

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

CONCLUSIONS

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

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

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

Recent advances in clinical practice: advances in cross-sectional imaging in inflammatory bowel disease

Endoscopy remains the reference standard for the diagnosis and assessment of patients with inflammatory bowel disease (IBD), but it has several important limitations. Cross-sectional imaging techniques such as magnetic resonance enterography (MRE) and intestinal ultrasound (IUS) are better tolerated and safer. Moreover, they can examine the entire bowel, even in patients with stenoses and/or severe inflammation. A variety of cross-sectional imaging activity scores strongly correlate with endoscopic measures of mucosal inflammation in the colon and terminal ileum. Unlike endoscopy, cross-sectional techniques allow complete visualisation of the small-bowel and assess for extraintestinal disease, which occurs in nearly half of patients with IBD. Extramural findings may predict outcomes better than endoscopic mucosal assessment, so cross-sectional techniques might help identify more relevant therapeutic targets. Coupled with their high sensitivity, these advantages have made MRE and IUS the primary non-invasive options for diagnosing and monitoring Crohn's disease; they are appropriate first-line investigations, and have become viable alternatives to colonoscopy. This review discusses cross-sectional imaging in IBD in current clinical practice as well as research lines that will define the future role of these techniques.

[Position paper on reporting of intestinal ultrasound findings in patients with inflammatory bowel disease]

BACKGROUND

Intestinal ultrasound is increasingly used for primary diagnosis, detection of complications and monitoring of patients with Crohn's disease and ulcerative colitis. Standardization of reporting is relevant to ensure quality of the methodology and to improve communication between different specialties. The current manuscript describes the features required for optimized reporting of intestinal ultrasound findings in inflammatory bowel disease (IBD).

METHODS

An expert consensus panel of gastroenterologists, radiologists, pathologists, paediatric gastroenterologists and surgeons conducted a systematic literature search. In a Delphi- process members of the Kompetenznetz Darmerkrankungen in collaboration with members of the German Society for Radiology (DRG) voted on relevant criteria for reporting of findings in intestinal ultrasound. Based on the voting results statements were agreed by expert consensus.

RESULTS

Clinically relevant aspects of intestinal ultrasound (IUS) findings have been defined to optimize reporting and to standardize terminology. Minimal requirements for standardized reporting are suggested. The statements focus on description of disease activity as well as on complications of IBD. Attributes of intestinal inflammation are described and illustrated by exemplary images.

CONCLUSION

The current manuscript provides practical recommendations on how to standardize documentation and reporting from intestinal ultrasound findings in patients with IBD.

Intestinal Conventional Ultrasonography, Contrast-Enhanced Ultrasonography and Magnetic Resonance Enterography in Assessment of Crohn's Disease Activity: A Comparison with Surgical Histopathology Analysis

BACKGROUND AND AIMS

Contrast-enhanced ultrasonography (CEUS) is a potential interesting method for assessing accurately Crohn's disease (CD) activity. We compared the value of intestinal ultrasonography (US) coupled with contrast agent injection with that of magnetic resonance enterography (MRE) in the assessment of small bowel CD activity using surgical histopathology analysis as reference.

METHODS

Seventeen clinically active CD patients (14 women, mean age 33 years) requiring an ileal or ileocolonic resection were prospectively enrolled. All performed a MRE and a US coupled with contrast agent injection (CEUS) less than 8 weeks prior to surgery. Various imaging qualitative and quantitative parameters were recorded and their respective performance to detect disease activity, disease extension and presence of complications was compared to surgical histopathological analysis.

RESULTS

The median wall thickness measured by US differed significantly between patients with non-severely active CD (n = 5) and those with severely active CD (n = 12) [7.0 mm, IQR (6.5-9.5) vs 10.0 mm, IQR (8.0-12.0), respectively; p = 0.03]. A non-significant trend was found with MRE with a median wall thickness in severe active CD of 10.0 mm, IQR (8.0-13.7) compared with 8.0 mm, IQR (7.5-10.5) in non-severely active CD (p = 0.07). The area under the ROC curve (AUROC) of the wall thickness assessed by US and MRE to identify patients with or without severely active CD on surgical specimens were 0.85, 95% CI (0.64-1.04), p = 0.03 and 0.80, 95% CI (0.56-1.01), p = 0.07, respectively. Among the parameters derived from the time-intensity curve during CEUS, time to peak and rise time were the two most accurate markers [AUROC = 0.88, 95% CI (0.70-1.04), p = 0.02 and 0.86, 95% CI (0.68-1.04), p = 0.03] to detect patients with severely active CD assessed on surgical specimens.

CONCLUSION

The accuracy of intestinal CEUS is close to that of conventional US to detect disease activity. A thickened bowel and shortened time to peak and rise time were the most accurate to identify CD patients with severe histological disease activity.

The value of multi-modes of ultrasound in evaluating segmental mucosal healing in patients with Crohn's disease

BACKGROUND

Mucosal healing, the result of endoscopic remission, is associated with prolonged clinical remission and delayed deterioration of Crohn's disease, which is significant and accompanied by reduced hospitalizations and surgeries. Currently, the relationship between ultrasonic parameters and mucosal healing remains controversial. To establish an ultrasonic regression model to evaluate mucosal healing, we conducted this preliminary study using multiple parameters from B-mode ultrasonography, colour Doppler flow imaging and shear wave elastography systematically.

METHODS

This study consisted of two single-centre investigations based on development and validation populations who received endoscopies (as the gold standard) and ultrasound. The involved bowel segments were divided into mucosal healing (MH) and nonmucosal healing (NMH) groups according to endoscopic results. Eight ultrasonic parameters were observed, including bowel wall thickness (BWT), mesenteric fat thickness (MFT), median modulus of elasticity (Emean), average shear wave velocity (SWV), Limberg scoring (LG), bowel wall stratification (BWS), ascites (AS) and lymph node enlargement (LN). We developed an ultrasonic regression model in the development phase to evaluate segmental mucosal healing and undertook prospective validation of this model.

RESULTS

A total of 124 patients with 380 involved bowel segments from the development and validation cohorts were evaluated. Eight ultrasonic parameters were significantly different between the two groups (P<0.05) in the development phase. Four significant parameters with better AUC performance were selected to establish an ultrasonic regression model to predict mucosal healing. The AUCs of this ultrasonic model were 0.975 and 0.942 in the development and validation cohorts, respectively.

CONCLUSION

The multimodal ultrasonic model has the potential to evaluate segmental mucosal healing in Crohn's disease.

Intestinal Ultrasound Early on in Treatment Follow-up Predicts Endoscopic Response to Anti-TNFα Treatment in Crohn's Disease

BACKGROUND

To assess treatment response, objective measures are superior to clinical improvement in Crohn's disease [CD]. Intestinal ultrasound [IUS] is an attractive, non-invasive alternative to endoscopy, demonstrating early transmural changes after treatment initiation. Therefore, we investigated IUS and contrast-enhanced ultrasound [CEUS] to predict [early] endoscopic treatment response.

METHODS

Consecutive patients with endoscopically active CD, starting anti-TNFα therapy, were included. Clinical, biochemical, IUS, and CEUS parameters at baseline [T0], after 4-8 weeks [T1] and 12-34 weeks [T2] were collected. The most severely inflamed segment at endoscopy (highest segmental Simplified Endoscopic Score for Crohn's Disease [SES-CD]) and IUS (highest segmental bowel wall thickness [BWT]) was identified. At T2, endoscopic response [decrease in SES-CD ≥ 50%] and remission [SES-CD = 0] were scored.

RESULTS

A total of 40 patients were included: 14 reached endoscopic remission and 17 endoscopic response. At T1 (3.1 mm [1.9-4.2] vs 5.3 mm [3.8-6.9], p = 0.005) and T2 (2.0 mm [1.8-3.1] vs 5.1 [3.0-6.3] mm, p = 0.002) BWT was lower in patients with endoscopic remission. At T1 and T2, 18% (area under the receiver operating curve [AUROC]: 0.77; odds ratio [OR]: 10.80, p = 0.012) and 29% [AUROC: 0.833; OR: 37.50, p = 0.006] BWT decrease predicted endoscopic response, respectively. To determine endoscopic remission, BWT 3.2 mm was most accurate [AUROC: 0.94; OR: 39.42, p < 0.0001] at T2. In addition, absence of colour Doppler signal [OR: 13.76, p = 0.03] and the CEUS parameter wash-out rate [OR: 0.76, p = 0.019] improved the prediction model.

CONCLUSIONS

Reduction in BWT, already after 4-8 weeks of follow-up, predicted endoscopic response and remission. CEUS parameters were of limited value. Furthermore, we have provided accurate cut-offs for BWT reflecting endoscopic response and remission at different time points.

ECCO-ESGAR Topical Review on Optimizing Reporting for Cross-Sectional Imaging in Inflammatory Bowel Disease

BACKGROUND AND AIMS

The diagnosis and follow up of patients with inflammatory bowel disease [IBD] requires cross-sectional imaging modalities, such as intestinal ultrasound [IUS], magnetic resonance imaging [MRI] and computed tomography [CT]. The quality and homogeneity of medical reporting are crucial to ensure effective communication between specialists and to improve patient care. The current topical review addresses optimized reporting requirements for cross-sectional imaging in IBD.

METHODS

An expert consensus panel consisting of gastroenterologists, radiologists and surgeons convened by the ECCO in collaboration with ESGAR performed a systematic literature review covering the reporting aspects of MRI, CT, IUS, endoanal ultrasonography and transperineal ultrasonography in IBD. Practice position statements were developed utilizing a Delphi methodology incorporating two consecutive rounds. Current practice positions were set when ≥80% of the participants agreed on a recommendation.

RESULTS

Twenty-five practice positions were developed, establishing standard terminology for optimal reporting in cross-sectional imaging. Assessment of inflammation, complications and imaging of perianal CD are outlined. The minimum requirements of a standardized report, including a list of essential reporting items, have been defined.

CONCLUSIONS

This topical review offers practice recommendations to optimize and homogenize reporting in cross-sectional imaging in IBD.

Evaluation of dynamic contrast-enhanced magnetic resonance imaging and diffusion-weighted imaging for predicting muscular hyperplasia/hypertrophy in Crohn's disease

OBJECTIVES

The existence of smooth muscle alteration in Crohn's disease (CD) is often neglected. It has been found that muscular hyperplasia/hypertrophy rather than fibrosis was the primary component of bowel wall thickening. This study aimed to assess the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion weighted imaging for the characterization of histopathologic tissue composition of CD, particularly smooth muscle hypertrophy, as well as inflammation and fibrosis.

METHODS

The study included patients diagnosed with CD who received MRI examination 30 days before resection from August 2016 to December 2020. A semiquantitative histological grading scheme was employed to evaluate the pathological tissues. Resected sections were matched with MRI according to pathological marks. Parameters evaluated included: mural thickness, T2 ratio, apparent diffusion coefficient value; and maximum enhancement, initial slope of increase, perfusion parameters of DCE-MRI and enhancement pattern. These parameters were compared with location-matched histopathological grade.

RESULTS

Ninety-one sections were enrolled in this retrospective study. When active inflammation is moderate or severe, volume transfer coefficient (K^trans), maximum enhancement (ME) and initial slope of increase (ISI) are lower, mural thickness is higher when a certain degree of smooth muscle alteration is present. When active inflammation is absent or mild, ME, mural thickness and ISI can differentiate the presence of predominant muscular alteration. By combining ME and thickness comparisons against their cutoff values to create a combined ordinal parameter, the area under the curve value for whether significant muscular alteration coexists with moderate or severe active inflammation was found to be 0.953.

CONCLUSIONS

MRI predicts the degree of inflammation, and can distinguish the degree of muscular alteration coexists with moderate or severe active inflammation with reasonable accuracy.

Gastrointestinal Ultrasound Can Predict Endoscopic Activity in Crohn's Disease

PURPOSE

 To explore the ability of gastrointestinal ultrasound (GIUS) to separate patients in endoscopic remission from patients with active disease in a heterogeneous hospital cohort with Crohn's disease (CD).

MATERIALS AND METHODS

 145 CD patients scheduled for ileocolonoscopy were prospectively included. The endoscopic disease activity was quantified using the Simple Endoscopic Score for Crohn's disease (SES-CD), and mucosal healing was strictly defined as SES-CD = 0. Ultrasound remission was defined as wall thickness < 3 mm (< 4 mm in the rectum). Additionally, SES-CD was compared to color Doppler, Harvey Bradshaw's index (HBI), C-reactive protein (CRP) and calprotectin. 23 patients were examined by two investigators for interobserver assessment.

RESULTS

 102 had active disease and 43 patients were in remission. GIUS yielded a sensitivity of 92.2 % and a specificity of 86 % for wall thickness and a sensitivity of 66.7 % and a specificity of 97.7 % for color Doppler. The sensitivity and specificity were 34.3 % and 88.4 %, respectively, for HBI, 35.7 % and 82.9 %, respectively, for CRP and 55.9 % and 82.1 %, respectively, for calprotectin. The interobserver analysis revealed excellent agreement for wall thickness (k = 0.90) and color Doppler (k = 0.91) measurements.

CONCLUSION

 GIUS has a high sensitivity for detecting endoscopic activity. Accordingly, bowel ultrasound has the potential to reduce the number of routine ileocolonoscopies in patients with CD.

Contrast Enhanced Ultrasound Molecular Imaging of Spontaneous Chronic Inflammatory Bowel Disease in an Interleukin-2 Receptor α−/− Transgenic Mouse Model Using Targeted Microbubbles

Inflammatory bowel disease (IBD) is a lifelong inflammatory disorder with relapsing–remission cycles, which is currently diagnosed by clinical symptoms and signs, along with laboratory and imaging findings. However, such clinical findings are not parallel to the disease activity of IBD and are difficult to use in treatment monitoring. Therefore, non-invasive quantitative imaging tools are required for the multiple follow-up exams of IBD patients in order to monitor the disease activity and determine treatment regimens. In this study, we evaluated a dual P- and E-selectin-targeted microbubble (MB_Selectin) in an interleukin-2 receptor α deficient (IL-2Rα^−/−) spontaneous chronic IBD mouse model for assessing long-term anti-inflammatory effects with ultrasound molecular imaging (USMI). We used IL-2Rα^−/− (male and female on a C57BL/6 genetic background; n = 39) and C57BL/6 wild-type (negative control; n = 6) mice for the study. USMI of the proximal, middle, and distal colon was performed with MB_Selectin using a small animal scanner (Vevo 2100) up to six times in each IL-2Rα^−/− mouse between 6–30 weeks of age. USMI signals were compared between IL-2Rα^−/− vs. wild-type mice, and sexes in three colonic locations. Imaged colon segments were analyzed ex vivo for inflammatory changes on H&E-stained sections and for selectin expression by immunofluorescence staining. We successfully detected spontaneous chronic colitis in IL-2Rα^−/− mice between 6–30 weeks (onset at 6–14 weeks) compared to wild-type mice. Both male and female IL-2Rα^−/− mice were equally (p = 0.996) affected with the disease, and there was no significant (p > 0.05) difference in USMI signals of colitis between the proximal, middle, and distal colon. We observed the fluctuating USMI signals in IL-2Rα^−/− mice between 6–30 weeks, which might suggest a resemblance of the remission-flare pattern of human IBD. The ex vivo H&E and immunostaining further confirmed the inflammatory changes, and the high expression of P- and E-selectin in the colon. The results of this study highlight the IL-2Rα^−/− mice as a chronic colitis model and are suitable for the long-term assessment of treatment response using a dual P- and E-selectin-targeted USMI.

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.

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, P_w; 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, P_w and MTT between T1 and T0 was higher in responders. Relapsers (21%) showed significantly lower reduction in delta PI and P_w at T1 and T2. At T3 they showed a new increase in PI and lower reduction in delta P_w. 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.

The role of the intestinal ultrasound in Crohn's disease diagnosis and monitoring

Crohn's disease is characterized by persistent or recurrent chronic inflammation that may affect any segment of the gastrointestinal tract. It has an oscillating evolution, with periods of activity alternating with periods of remission. Crohn's disease has a significant impact on the economic status due to its increasing prevalence, often affecting young people. Suitable management for these patients involves frequent evaluations. Even though colonoscopy is the gold standard for the assessment of severity and mucosal healing, it is an invasive maneuver, not easily accepted by patients, and it does not have good repeatability. Intestinal ultrasound has the advantage of being non-irradiating, non-invasive, well-tolerated, cheap, and easy to repeat. Ultrasound parameters such as bowel wall thickness, intestinal wall architecture, intramural vascularisation, proliferation of mesenteric fatty conjunctive tissue, and intraperitoneal fluid can provide good information regarding the severity of the disease, the differentiation between remission and relapse, and its complications. Some of the latest studies show good correlations between ultrasound parameters and inflammation markers (C-reactive protein, fecal calprotectin) and clinical severity scores of Crohn's disease. Consequently, the importance of intestinal ultrasound has increased lately, and recent studies support its use to evaluate the severity of inflammation, differentiate between active disease and relapse, monitor therapy response and guide treatment, evaluate prognosis, and diagnose complications.

Ultrasonographic Evaluation of Intestinal Fibrosis and Inflammation in Crohn's Disease. The State of the Art

The evaluation of the degree of inflammation and fibrosis, intrinsic elements in intestinal wall damage of Crohn’s disease, is essential to individuate the extent of the lesions and the presence of strictures. This information will contribute to the choice of the appropriate therapeutic approach, the prediction of the response to therapy and the course of the disease. The accurate evaluation of the extent and severity of inflammation and/or fibrosis in Crohn’s disease currently requires histopathological analysis of the intestinal wall. However, in clinical practice and research, transmural assessment of the intestinal wall with cross sectional imaging is increasingly used for this purpose. The B-mode ultrasonograhic characteristics of the intestinal wall, the assessment of its vascularization by color Doppler and I.V. contrast agents, and the evaluation of the mechanical and elastic properties by sonoelastography, may provide useful and accurate information on the severity and extent of inflammation and intestinal fibrosis in Crohn’s disease. The purpose of this review is to provide an update on current sonographic methods to discriminate inflammation and fibrosis in Crohn’s disease.

Non-invasive Ultrasonographic Score for Assessment of the Severity of Inflammatory Bowel Disease

Intestinal ultrasound and shear wave elastography have gained increasing interest because of their promising results in the assessment of inflammatory bowel disease. The aim of this study was to find an ultrasonographic score to replace invasive endoscopic procedures for the management of these patients. The score includes ultrasound parameters that correlate well with clinical severity scales and inflammatory markers: bowel wall thickness, the Limberg score, disease extension and acoustic radiation force impulse measurements. The score proved to be well correlated with the Harvey Bradshaw Index, the Mayo score, C-reactive protein and fecal calprotectin. For Crohn's disease, a cutoff value of 8 points could identify active disease with 81.81% sensitivity and 83% specificity, while for ulcerative colitis, a cutoff value of 7 points could discriminate between remission and relapse with 86.85% sensitivity and 94% specificity. In conclusion, our ultrasonographic score can differentiate relapse from remission in inflammatory bowel disease.

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.

Contrast-enhanced ultrasound of the pediatric bowel

Contrast-enhanced ultrasound (CEUS) has emerged as a valuable modality for bowel imaging in adults and children. CEUS enables visualization of the perfusion of the bowel wall and of the associated mesentery in healthy and disease states. In addition, CEUS images can be used to make quantitative measurements of contrast kinetics, allowing for objective assessment of bowel wall enhancement. Bowel CEUS is commonly applied to evaluate inflammatory bowel disease and to monitor treatment response. It has also been applied to evaluate necrotizing enterocolitis, intussusception, appendicitis and epiploic appendagitis, although experience with these applications is more limited. In this review article, we present the current experience using CEUS to evaluate the pediatric bowel with emphasis on inflammatory bowel disease, extrapolating the established experience from adult studies. We also discuss emerging applications of CEUS as an adjunct or problem-solving tool for evaluating bowel perfusion.

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.

Ultrasound findings of Crohn's disease: correlation with MR enterography

Crohn's disease is a chronic inflammatory bowel disease characterized by periods of relative inactivity alternating with acute flare-ups. Imaging techniques play a fundamental role in the diagnosis and follow-up of Crohn's disease, providing information on the extent of disease, disease activity, and the presence of extramural complications. Because of the frequent re-evaluation required by the relapsing nature of Crohn's disease and the relative young age at which most patients are diagnosed, techniques that use ionizing radiation are best avoided in monitoring this population. Thus, magnetic resonance enterography (MRE) and ultrasonography (US) are the preferable techniques. Various studies have demonstrated that US is accurate in assessing the gut. Despite some clear advantages over MRE, US has long been underused in the evaluation of intestinal disease. This review presents an overview of the main imaging findings in Crohn's disease, correlating representative US images with MRE and surgical pathology specimens. We conclude that US reliably depicts both bowel-related and mesenteric features of Crohn's disease and US findings correlate strongly with MRE findings.

Correlation of minimally invasive imaging techniques to assess intestinal mucosal perfusion with established markers of chronic inflammatory enteropathy in dogs

Background

Minimally invasive diagnostic imaging techniques to detect intestinal inflammation in dogs are lacking. Contrast‐enhanced ultrasound (CEUS) and endoscopic narrow band imaging‐like endoscopy (Storz Professional Image Enhancement System [SPIES]) might allow quantification of intestinal mucosal perfusion and microvessel density in chronic inflammatory enteropathy (CIE) of dogs.

Hypothesis/Objectives

Markers of mucosal perfusion as determined by CEUS and SPIES endoscopy are potentially useful diagnostic markers to help characterize CIE and correlate with histological inflammation type and severity.

Animals

Thirty client‐owned dogs diagnosed with CIE at a referral hospital were prospectively enrolled.

Materials and Methods

Data from CEUS, SPIES, and white light (WL) endoscopy were correlated with World Small Animal Veterinary Association (WSAVA) endoscopy and histology scores and vessel density as determined by immunohistochemistry for von Willebrand factor (vWF). Automated linear modeling was used to determine predictors of endoscopic and histologic severity.

Results

Duodenal histology correlated with SPIES data (area percentage value, rho = 0.424, P = .04). White light endoscopy parameters correlated with SPIES parameters in the duodenum. Colonic histology correlated positively with CEUS, whereas colonic CEUS parameters correlated inversely with vWF expression. Several duodenal parameters combined predicted duodenal histology scores to a level of 73.4%. For the colon, 2 parameters contributed more than others to 73.1%.

Conclusion and Clinical Importance

Minimally invasive CEUS and SPIES appear feasible to assess intestinal perfusion in CIE. Use of SPIES endoscopy may be promising for assessing small intestinal inflammation, whereas CEUS could be used to assess colonic perfusion and inflammation. Both techniques need to be investigated further for their clinical utility.

Recommendations of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis (GETECCU) on the use of abdominal ultrasound in inflammatory bowel disease

Ultrasound has an excellent diagnostic performance when Crohn's disease is suspected, when performing an activity assessment, or determining the extension and location of Crohn's disease, very similar to other examinations such as MRI or CT. It has a good correlation with endoscopic lesions and allows the detection of complications such as strictures, fistulas or abscesses. It complements colonoscopy in the diagnosis and, given its tolerance, cost and immediacy, it can be considered as a good tool for disease monitoring. In ulcerative colitis, its role is less relevant, being limited to assessing the extent and activity when it is not possible with other diagnostic techniques or if there are doubts with these. Despite its advantages, its use in inflammatory bowel disease (IBD) is not widespread in Spain. For this reason, this document reviews the advantages and disadvantages of the technique to promote knowledge about it and implementation of it in IBD Units.

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.

Usefulness of intestinal ultrasound in inflammatory bowel disease

Imaging techniques play a fundamental role in the initial diagnosis and follow-up of inflammatory bowel disease. Intestinal ultrasound has high sensitivity and specificity in patients with suspected Crohn's disease and in the detection of inflammatory activity. This technique enables the early diagnosis of intra-abdominal complications such as stenosis, fistulas, and abscesses. It has also proven useful in monitoring the response to treatment and in detecting postsurgical recurrence. Technical improvements in ultrasound scanners, technological advances such as ultrasound contrast agents and elastography, and above all increased experience have increased the role of ultrasound in the evaluation of the gastrointestinal tract. The features that make ultrasound especially attractive include its wide availability, its noninvasiveness and lack of ionizing radiation, its low cost, and its good reproducibility, which is important because it is easy to repeat the study and the study is well tolerated during follow-up. This review summarizes the role of intestinal ultrasound in the detection and follow-up of inflammatory bowel disease.

Contrast-enhanced US in Pediatric Patients: Overview of Bowel Applications

Contrast material-enhanced US is a technique that is approved by the U.S. Food and Drug Administration for the characterization of liver lesions and intravesicular applications in children; however, contrast-enhanced US has several other pediatric applications in clinical practice. The most common application is for patients with inflammatory bowel disease (IBD). Contrast-enhanced US can be used to diagnose IBD, distinguish regions of active or chronic inflammation of the bowel wall, and evaluate associated complications such as abscesses, fistulas, and strictures. Dynamic contrast material evaluation provides qualitative and quantitative information about mural and mesenteric blood flow, which is essential in the determination of disease activity in these patients. It also has the potential to provide a means of monitoring the response to therapy beyond endoscopy or MR enterography. In addition to its use for IBD, contrast-enhanced US can be used to assess for bowel perfusion when problem solving in patients with necrotizing enterocolitis, neonatal bowel infarction, or intussusception. It is a useful imaging technique to fortify diagnoses that may otherwise be indeterminate, such as appendicitis, epiploic appendagitis, intraluminal bowel masses, and complex cysts. Finally, innovative applications such as shear-wave elastography have the potential to provide information about the stiffness of the bowel wall. Online supplemental material is available for this article. ©RSNA, 2020 See discussion on this article by Watson and Humphries.

Impact of intestinal ultrasound on the management of patients with inflammatory bowel disease: how to apply scientific evidence to clinical practice

Technological improvements and growing sonographers' expertise boost the role of intestinal ultrasound (IUS) in assessing patients with inflammatory bowel diseases (IBD). Non-invasiveness, low cost and good reproducibility make IUS attractive. Leveraging on the Authors' long-term field experience, this review focuses on the IUS role in IBD patients' clinical management. For detecting IBD, particularly Crohn's disease, the IUS parameters - above all the evidence of a thickened bowel wall (BWT) - show very good diagnostic accuracy similar to that of MRI or CT scan. The standard IUS parameters are not accurate enough to detect inflammatory activity, but intravenous contrast-enhanced US (CEUS) is highly accurate in ruling active inflammation out. However, its routinely use remains limited in clinical practice and its parameters need standardization. IUS is accurate in detecting IBD main complications: in particular, fistulae and abscesses. As to stenosis the recent introduction of IUS-based elastographic techniques allows to differentiate prevalently inflammatory from highly fibrotic strictures. IUS proves valid also for monitoring IBD patients. In particular, the evidence of transmural healing, defined as BWT normalization, has got an important prognostic meaning, as associated with better long-term clinical outcomes. Post-surgery CD recurrence can be suggested by early IUS assessment.

Pursuing therapeutic success in Crohn’s disease: A matter of definition, tools and longterm outcomes

Management of Crohn’s disease (CD) based on symptom control is a tale of the past as new treatment strategies aim toward a “treat to target” concept and to a patient-tailored approach. Defining treatment goals and assessing therapeutic success have been in the center of IBD research in the past years. Clinical remission and mucosal healing are well-established treatment goals by current recommendations, although prospective data is required to determine whether achieving these targets is enough to alter disease natural course. Furthermore, there is no standard in assessing therapeutic success. Low relapse and hospitalization rates, as well as a low need of surgery are indicators of a successful treatment. Close monitoring is part of the new therapeutic strategy. Monitoring tools are numerous, comprising clinical, biological, endoscopic and imaging scores or parameters but are far from being perfect. The traditional strategy of managing CD patients based on clinical symptoms and response to treatment did not improve the long-term outcomes. Clinical activity scores are frequently used in clinical trials and daily practice, but their use alone is not an accurate measure of inflammation. Endoscopic remission is associated with a lower risk of complications and a better long-term prognostic. Several guidelines include recommendations regarding surveillance endoscopy, but there is an open debate regarding the follow-up intervals. Cross-sectional imaging techniques play a complementary role in assessing transmural inflammation and in identifying extra-intestinal complications of CD and should be used in conjunction with endoscopy. Therapeutic drug monitoring is essential in assessing loss of response and making therapeutic decisions, although firm recommendations are not implemented into daily practice. Extraintestinal manifestations are often disregarded when discussing monitoring protocols. There is no current guideline indication for extraintestinal manifestations monitoring during remission periods.

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.

Imaging in discriminating intestinal tuberculosis and Crohn's disease: past, present and the future

Introduction: Intestinal tuberculosis (ITB) and Crohn's disease (CD) have similar clinical presentation, but require different treatment approaches. Despite advances in various endoscopic, imaging, microbiological, and histological techniques, the differentiation of these two entities is often difficult. Newer radiological and image acquisition modalities have now become indispensable tools for evaluation of these two diseases.Areas covered: This review summarizes the currently available literature on various radiological investigations to differentiate ITB from CD. This review also enumerates the newer modalities in image acquisition techniques and their potential role for differentiating these two diseases. At present abdominal computed tomography (CT) scan is used as a first line investigation for differentiating ITB from CD. Magnetic resonance imaging (MRI) is preferred in pediatric patients and for follow-up studies.Expert opinion: Role of newer modalities like contrast enhanced abdominal ultrasound, perfusion CT, advanced MRI and positron emission tomography (PET) is evolving and requires further exploration. Till further robust studies are available, differentiation between ITB and CD requires use of a combination of clinical, endoscopic, serological, histological, and radiological parameters rather than relying on a single test.

Chronic Model of Inflammatory Bowel Disease in IL-10-/- Transgenic Mice: Evaluation with Ultrasound Molecular Imaging

Objective: Acute mouse models of inflammatory bowel disease (IBD) fail to mirror the chronic nature of IBD in patients. We sought to develop a chronic mouse IBD model for assessing long-term anti-inflammatory effects with ultrasound molecular imaging (USMI) by using dual P- and E-selectin targeted microbubbles (MB_Selectin). Materials and Methods: Interleukin 10 deficient (IL-10^-/- on a C57BL/6 genetic background; n=55) and FVB (n=16) mice were used. In IL-10^-/-mice, various experimental regimens including piroxicam, 2,4,6-trinitrobenzenesulfonic acid (TNBS) or dextran sulfate sodium (DSS), respectively were used for promoting colitis; colitis was induced with DSS in FVB mice. Using clinical and small animal ultrasound scanners, evolution of inflammation in proximal, middle and distal colon, was monitored with USMI by using MB_Selectin at multiple time points. Imaged colon segments were analyzed ex vivo for inflammatory changes on H&E staining and for P-selectin expression on immunofluorescence staining. Results: Sustained colitis was not detected with USMI in IL-10^-/- or FVB mice with various experimental regimens. USMI signals either gradually decreased after the colitis enhancing/inducing drug/agents were discontinued, or the mortality rate of mice was high. Inflammation was observed on H&E staining in IL-10^-/- mice with piroxicam promotion, while stable overexpression of P-selectin was not found on immunofluorescence staining in the same mice. Conclusion: Sustained colitis in IL-10^-/- mice induced with piroxicam, TNBS or DSS, and in FVB mice induced with DSS, was not detected with USMI using MB_Selectin, and this was verified by immunofluorescence staining for inflammation marker P-selectin. Thus, these models may not be appropriate for long-term monitoring of chronic colitis and subsequent treatment response with dual-selectin targeted USMI.

Assessment of angiogenesis in rabbit orthotropic liver tumors using three-dimensional dynamic contrast-enhanced ultrasound compared with two-dimensional DCE-US

OBJECTIVES

To evaluate quantitative three-dimensional (3D) dynamic contrast-enhanced ultrasound (DCE-US) in the assessment of tumor angiogenesis using an orthotropic liver tumor model.

METHODS

Nine New Zealand white rabbits with liver orthotropic VX2 tumors were established and imaged by two-dimensional (2D) and 3D DCE-US after SonoVue^® bolus injections. The intraclass correlation coefficients of perfusion parameters, including peak intensity (PI), mean transit time, time to peak, and area under the curve, were calculated based on time-intensity curve. The percentage area of microvascular (PAMV) and the expression of vascular endothelial growth factor (VEGF) were both evaluated by immunohistochemical analysis and weighted by the tumor activity area ratio. Correlations between quantitative and histologic parameters were analyzed.

RESULTS

The reproducibility of 3D DCE-US quantitative parameters was excellent (ICC 0.91-0.99); but only PI showed high reproducibility (ICC 0.97) in 2D. None of the parameters of quantitative 2D DCE-US were significantly correlated with weighted PAMV or VEGF. For 3D DCE-US, there was a positive correlation between PI and weighted PAMV (r = 0.74, P = 0.04) as well as VEGF (r = 0.79, P = 0.02).

CONCLUSION

Quantitative parameters of 3D DCE-US show feasibility, higher reproducibility and accuracy for the assessment of tumor angiogenesis using an orthotropic liver tumor model compared with 2D DCE-US.

Intravenous Contrast-Enhanced Ultrasound for Assessing and Grading Postoperative Recurrence of Crohn's Disease

PURPOSE

The aim was to investigate the contribution of contrast-enhanced ultrasound (CEUS) to improve the results of US in the evaluation of recurrence in postsurgical Crohn's disease (CD) and establish its role in the assessment of the severity.

METHODS

Anastomotic site was assessed in 108 postsurgical CD patients with B-mode, color Doppler and CEUS. Bowel wall thickness (WT), transmural complications or stenosis, color Doppler grade, and bowel wall contrast enhancement (BWCE)-using time-intensity curves-were correlated with endoscopic Rutgeerts score. A receiver operating characteristic (ROC) curve was built to establish the best cutoff to predict recurrence and the severity. A US scoring system was elaborated in order to determine the grade of recurrence.

RESULTS

Ileocolonoscopy detected recurrence in 90 (83.3%) subjects and severe recurrence in 62. WT ≥ 3 mm had an accuracy of 90.7% in the detection of endoscopic recurrence. The combination of parameters-WT ≥ 3 mm and BWCE (≥ 46%)-demonstrated similar accuracy (90.7%). A WT ≥ 5 mm showed the best specificity (100%) for the diagnosis of recurrence and a WT ≥ 6 mm the best specificity (95.7%) for the detection of severe recurrence. The combination of sonographic parameters-WT ≥ 6 mm or WT between 5 and 6 mm with BWCE ≥ 70%, or complications-obtained the best results grading the recurrence (sensitivity, specificity, and accuracy of 90.3%, 87%, and 88.9%, respectively).

CONCLUSIONS

US shows high sensitivity and specificity for the diagnosis of postsurgical recurrence. When combined with CEUS, it can improve the detection of severe recurrence.

The Role of Intravenous Contrast Agent in the Sonographic Assessment of Crohn's Disease Activity: Is Contrast Agent Injection Necessary?

BACKGROUND AND AIMS

Contrast-enhanced ultrasound [CEUS] is reported to be superior to wall thickness or colour Doppler imaging [CDI] in predicting disease activity using endoscopy as the reference standard. Our aims were to determine in patients with Crohn's disease [CD] whether the evaluation of wall thickness or CDI before CEUS examination could help to decide when the injection of contrast agent is justified as a means for detecting disease activity as determined at endoscopy, without reducing the accuracy of ultrasound.

METHODS

In total, 180 patients with CD underwent both colonoscopy and ultrasound, including mural thickness, CDI and CEUS evaluation, prospectively as part of clinical care. A receiver operating characteristic curve was constructed to determine the area under the curve and the best cutoff of wall thickness and ultrasound enhancement value to discriminate between endoscopically active and inactive disease. Several analyses were carried out to determine which parameter or combination of parameters best detected endoscopic activity.

RESULTS

Comparative evaluation of the different analysis showed that wall thickness alone classified 76.6% of patients correctly, CDI alone 72.7%, and thickness plus CDI 72.2%. The use of CEUS significantly improved the diagnosis of active disease: CEUS alone correctly classified 164 of 180 patients [91.1%], combined analysis of CDI and CEUS 165 of 180 [91.7%], and combined analysis of thickness, CDI and CEUS 164 of 180 [91.1%], without significant differences. Patients with CDI grade 2 or 3 showed a predictive positive value of 97% to detect disease activity, similar to CEUS [100%].

CONCLUSION

CEUS is the most reliable ultrasound criterion for endoscopic disease activity. However, the use of a contrast agent is probably not justified to assess disease activity for patients with CDI grade 2/3.

Early Predictors of the Long-term Response to Therapy in Patients With Crohn Disease Derived From a Time-Intensity Curve Analysis After Microbubble Contrast Agent Injection

OBJECTIVES

The aim of this study was to identify early predictors of the long-term response to therapy in patients with Crohn disease (CD) from time-intensity curves obtained after microbubble injection.

METHODS

One hundred fifteen consecutive patients with a proven diagnosis of CD involving the terminal ileal loop who were scheduled to begin pharmacologic therapy with biologics (infliximab or adalimumab) were scanned after sulfur hexafluoride-filled microbubble injection before the beginning and at the end of the sixth week of treatment. The absolute value and percentage change of each semiquantitative kinetic parameter (peak enhancement, time to peak enhancement, rise time, mean transit time, wash-in and wash-out rates, area under the curve [AUC] for the whole time-intensity curve, AUC during wash-in, AUC during wash-out, and wash-in perfusion index) as measured on the terminal ileal tract and adjacent reactive mesenteric fat were calculated from time-intensity curves. Patients were followed for at least 24 months with redetermination of the Crohn Disease Activity Index and with at least 1 endoscopy within 18 weeks after the beginning of pharmacologic treatment. The absolute values and percentage changes of kinetic parameters were assessed as potential predictors of the therapeutic outcome by a logistic regression analysis.

RESULTS

The study group included 66 male and 49 female patients (mean age ± SD, 45.76 ± 11 years). The pretreatment values and percentage changes of the peak enhancement, AUC, AUC during wash-in, and AUC during wash-out were found to be predictors (P < .05) of the long-term therapeutic outcome.

CONCLUSIONS

The analysis of time-intensity curves obtained after microbubble contrast agent injection provides early predictors of the long-term therapeutic outcome in patients with CD.

Bowel Ultrasound State of the Art: Grayscale and Doppler Ultrasound, Contrast Enhancement, and Elastography in Crohn Disease

Bowel ultrasound (US) is accurate for assessing bowel inflammation and complications in Crohn disease. Additionally, contrast-enhanced US provides a quantitative, objective measurement of inflammatory activity in inflammatory bowel disease, and shear wave elastography predicts the stiffness of bowel, an increase of which suggests less response to medical therapy, often necessitating surgery. Overall, bowel US is an excellent, safe, and repeatable choice for routine surveillance and for urgent imaging. We describe an approach to evaluating inflammatory bowel disease and review its features on standard grayscale US with Doppler imaging and show how contrast-enhanced US and shear wave elastography can distinguish between inflammatory and fibrostenotic bowel.

Persistent Enhancement on Contrast-Enhanced Ultrasound Studies of Severe Crohn's Disease: Stuck Bubbles?

A small population of patients with severe Crohn's disease (CD) exhibit atypical lack of intensity decline on intestinal contrast-enhanced ultrasound. From a retrospective CD cohort examined with contrast-enhanced ultrasound, 104 patients were identified. Twenty study patients with severe active disease exhibited high peak enhancement (>23 dB) and minimal decline. From the same cohort, 84 control patients also exhibited high peak enhancement >23dB, but with typical intensity decline. Patient outcomes were assessed. Time-intensity curve analysis revealed a significantly higher (p < 0.0001) area under the curve (44.7 ± 1.5 dB·s), washout time and intensities at 60s and 120s in the study population compared with controls (40.0 ± 1.1 dB·s). Study patients had a worse overall outcome with surgery in 30% versus 10% (p = 0.027) during follow-up. Heightened enhancement with lack of decline on contrast-enhanced ultrasound suggests microbubbles are stuck within the inflamed bowel wall for an extended period. This observation occurs in patients with severe disease and a bad outcome.

US Molecular Imaging of Acute Ileitis: Anti-Inflammatory Treatment Response Monitored with Targeted Microbubbles in a Preclinical Model

Purpose To evaluate whether dual-selectin-targeted US molecular imaging allows longitudinal monitoring of anti-inflammatory treatment effects in an acute terminal ileitis model in swine. Materials and Methods The Institutional Animal Care and Use Committee approved all animal studies. Fourteen swine with chemically induced acute terminal ileitis (day 0) were randomized into the following groups: (a) an anti-inflammatory treatment group (n = 8; meloxicam, 0.25 mg per kilogram of body weight; prednisone, 0.5 mg/kg) and (b) a control group (n = 6; saline). US molecular imaging was performed with a clinical US machine after intravenous injection of clinically translatable dual P- and E-selectin-targeted microbubbles (5 × 108/kg). Three inflamed bowel segments per swine were imaged at baseline, as well as on days 1, 3, and 6 after treatment initiation. At day 6, bowel segments were analyzed ex vivo for selectin expression levels by using quantitative immunofluorescence. Results After induction of inflammation, US molecular imaging signal increased at day 1 in both animal groups (P < .001). At day 3, signal in the treatment group decreased (P < .001 vs day 1), while signal in control animals did not significantly change (P = .18 vs day 1) and was higher (P = .001) compared with that in the treatment group. At day 6, signal in the treatment group further decreased and remained lower (P = .02) compared with that in the control group. Immunofluorescence confirmed significant (P ≤ .04) downregulation of both P- and E-selectin expression levels in treated versus control bowel segments. Conclusion Dual-selectin-targeted US molecular imaging allows longitudinal monitoring of anti-inflammatory treatment effects in a large-animal model of acute ileitis. This supports further clinical development of this quantitative and radiation-free technique for monitoring inflammatory bowel disease. © RSNA, 2018 Online supplemental material is available for this article.

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.

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.