Ultrasound assessment of vascularization of the thickened terminal ileum wall in Crohn's disease patients using a low-mechanical index real-time scanning technique with a second generation ultrasound contrast agent

New Intestinal Ultrasound Score for Assessing Inflammatory Bowel Disease Activity and Identifying Severity

PURPOSE

The purpose of this study is to propose new ultrasound scores to assess inflammatory bowel disease (IBD) activity and to analyze their accuracy in assessing disease severity. In addition to this, to validate that intestinal ultrasound can be used as a follow-up tool for the assessment of IBD.

METHODS

One hundred and thirty-six adult IBD patients who underwent intestinal ultrasound. Patients were divided into two groups based on colonoscopic findings: 93 patients with UC, 43 patients with CD. UC patients and CD patients were divided into active and inactive groups based on colonoscopic findings, respectively. After forming scores, cut-off values, sensitivity, and specificity were calculated using receiver operating characteristic (ROC) analysis, respectively.

RESULTS

Both in UC patients and in CD patients, bowel wall thickness (BWT) and vascular index (VI) were much higher in the active group compared with the inactive group, CEUS mode III, IV, CDFI grades 3-4, fat wrapping, and lost stratification were more likely to imply active disease. In UC patients only, Young's modulus value was much higher in the active group compared with the inactive group.

CONCLUSION

The new intestinal ultrasound scores can be used to assess UC and CD activity and may be useful in identifying severe endoscopic activity in IBD.

Small bowel ultrasound: friend or foe?

PURPOSE OF REVIEW

Crohn's disease (CD), requires accurate diagnosis and regular monitoring to manage disease activity, prevent complications, and improve outcomes. Intestinal ultrasound (IUS) has emerged as a noninvasive, real-time imaging modality, offering a valuable alternative to traditional diagnostic techniques such as magnetic resonance enterography (MRE), endoscopy and capsule endoscopy (CE). This review examines recent advances in IUS for the diagnosis and monitoring of small bowel CD, with a focus on its applications, benefits, and limitations.

RECENT FINDINGS

Recent studies have demonstrated that IUS provides high sensitivity and specificity in detecting key markers of disease activity, including bowel wall thickness (BWT), bowel wall flow (BWF), and bowel wall stratification (BWS). Advances in IUS techniques, such as elastography and contrast-enhanced ultrasound (CEUS), have expanded its diagnostic and prognostic capabilities, potentially enabling differentiation between inflammation and fibrosis. However, challenges remain, including operator dependency, variability in scoring systems, and reduced sensitivity for superficial mucosal abnormalities. Efforts to standardize parameters and improve training have shown promise in addressing these limitations.

SUMMARY

IUS is a critical complementary tool for assessing disease activity, transmural healing, and postoperative recurrence in small bowel CD. Its noninvasiveness, cost-effectiveness, and real time assessment make it well suited for routine clinical use. Nonetheless, further multicentre studies are needed to validate scoring systems, optimize integration with other modalities, and improve consistency across clinical settings. IUS holds significant potential for advancing personalized care in small bowel CD, though ongoing research is required to refine its applications and maximize its clinical utility.

Gastrointestinal Ultrasound in Infectious Diseases: A Comprehensive Review

Infectious diseases affecting the gastrointestinal tract often present diagnostic challenges due to the variability in clinical manifestations and overlapping symptoms. Ultrasound imaging has emerged as a valuable tool in the assessment of gastrointestinal pathologies, offering non-invasive and real-time visualization of anatomical structures. This review aims to explore the role of ultrasound in the diagnosis and management of infectious diseases involving the gastrointestinal tract. We discuss the imaging features of various infectious etiologies, such as bacterial, viral, and parasitic infections, highlighting characteristic findings on ultrasound scans. Additionally, we provide insights into the utility of ultrasound for the assessment of treatment response. Through a comprehensive analysis of existing literature and clinical case studies, this review underscores the significance of ultrasound imaging as a frontline modality in the diagnosis and management of infectious diseases affecting the gastrointestinal tract.

Prospective study on the impact of BEAM versus FEAM conditioning on occurrence of neutropenic enterocolitis and on transplant outcome in lymphoma patients

Introduction

Carmustine (BCNU), etoposide, cytarabine, and melphalan (BEAM) are a widely used high-dose chemotherapy regimen for autologous stem cell transplantation transplant (ASCT) in lymphoid malignancies. During BCNU shortages, some centers switched to fotemustine-substituted BEAM (FEAM). Neutropenic enterocolitis (NEC) is a life-threatening complication occurring after intestinal mucosa damage related to intensive chemotherapy. NEC mortality may be up to 30%-50%. In our study, we compared NEC incidence, symptoms, mortality, and transplant outcome in terms of overall survival (OS) and progression-free survival (PFS) in the BEAM vs. FEAM groups. Furthermore, we compared the cost of hospitalization of patients who did vs. patients who did not experience a NEC episode (NECe).

Methods

A total of 191 patients were enrolled in this study (N = 129 and N = 62 were conditioned with BEAM and FEAM, respectively). All patients received bed-side high-resolution ultrasound (US) for NEC diagnosis.

Results and discussion

NEC incidence and NEC-related mortality were similar in the BEAM and FEAM groups (31% and 40.3%, p = 0.653, and 5% and 8%, p = 0.627, respectively). At a median follow-up of 116 months, no difference was noted between BEAM vs. FEAM groups in terms of OS and PFS (p = 0.181 and p = 0.978, respectively). BEAM appeared equivalent to FEAM in terms of NEC incidence and efficacy. The high incidence of NEC and the low mortality is related to a timely US diagnosis and prompt treatment. US knowledge in NEC diagnosis allows to have comparable days of hospitalization of patients NECpos vs. patients NECneg. The cost analysis of NECpos vs. NECneg has been also performed.

Application of Dynamic Contrast-Enhanced Ultrasound in Evaluation the Activity of Crohn's Disease

BACKGROUND AND OBJECTIVE

The dynamic assessment of disease activity during the follow-up of patients with Crohn's disease (CD) remains a significant challenge. In this study, we aimed to identify the role of dynamic contrast-enhanced ultrasound (DCE-US) in the evaluation of activity of CD.

METHODS

In the retrospective study, patients diagnosed with CD in our hospital were included. All the diagnoses were confirmed by clinical symptoms and ileocolonoscopical results. All patients underwent intestinal ultrasound and contrast-enhanced ultrasound (CEUS) examinations within 1 week of the ileocolonoscopy examinations. Acuson Sequoia (Siemens Healthineers, Mountain View, CA, USA) and Resona R9 Elite (Mindray Medical Systems, China) with curved array and Line array transducers were used. The CEUS examination was performed with SonoVue (Bracco SpA, Milan, Italy). DCE-US analysis was performed by UltraOffice (version: 0.3-2010, Mindray Medical Systems, China) software. Two regions of interest (ROIs) were set in the anterior section of the infected bowel wall and its surrounding normal bowel wall 2 cm distant from the inflamed area. Time-intensity curves (TICs) were generated and quantitative perfusion parameters were obtained after curve fittings. The Simple Endoscopic Score for Crohn's disease (SES-CD) was regarded as the reference standard to evaluate the activity of CD. The receiver operating characteristic curve (ROC) analyses were used to determine the diagnostic efficiency of DCE-US quantitative parameters.

RESULTS

From March 2023 to November 2023, 52 CD patients were included. According to SES-CD score, all patients were divided into active group with the SES-CD score > 5 (n = 39) and inactive group SES-CD score < 5 (n = 13). Most of the active CD patients showed bowel wall thickness (BWT) > 4.2 mm (97.4%, 38/39) or mesenteric fat hypertrophy (MFH) on intestinal ultrasound (US) scan (69.2%, 27/39). Color Doppler signal of the bowel wall mostly showed spotty or short striped blood flow signal in active CD patients (56.4%, 22/39). According to CEUS enhancement patterns, most active CD patients showed a complete hyperenhancement of the entire intestinal wall (61.5%, 24/39). The TICs of active CD showed an earlier enhancement, higher peak intensity, and faster decline. Among all CEUS quantitative parameters, amplitude-derived parameters peak enhancement (PE), wash-in area under the curve (WiAUC), wash-in rate (WiR), wash-in perfusion index (WiPI), and wash-out rate (WoR) were significantly higher in active CD than in inactive CD (p < 0.05). The combined AUROC of intestinal ultrasound features and DCE-US quantitative perfusion parameters in the diagnosis of active CD was 0.987, with 97.4% sensitivity, 100% specificity, and 98.1% accuracy.

CONCLUSIONS

DCE-US with quantitative perfusion parameters is a potential useful noninvasive imaging method to evaluate the activity of Crohn's disease.

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.

Impact of different chemotherapy regimens on intestinal mucosal injury assessed with bedside ultrasound: a study in 213 AML patients

Introduction

Neutropenic enterocolitis (NEC) is a life-threatening complication reported in patients with acute myeloid leukemia (AML) following chemotherapy (CHT). Intensive induction and consolidation CHT may damage intestinal mucosa leading to a NEC episode (NECe). NEC reported mortality may be up to 30-60%. Early US-guided bed-side diagnosis and prompt treatment may substantially improve the survival. An emerging worldwide concern is the intestinal colonization by multi-drug-resistant bacteria especially when patients are exposed to chemotherapy regimens potentially correlated to mucosal damage.

Methods

In our study we prospectively enrolled all AML patients admitted in our leukemia unit to receive intensive induction and consolidation chemotherapy and experiencing chemotherapy-induced-neutropenia (CHTN).

Results and discussion

Overall, we enrolled N=213 patients from 2007 to March 2023. We recorded N=465 CHTN, and N=42 NECe (9.0% incidence). The aim of our study was to assess which chemotherapy regimens are more associated with NEC. We found that ALM1310, followed by 7 + 3 (daunorubicin), 7 + 3 (idarubicin), 5 + 3 + 3 (cytarabine, etoposide, idarubicin), and AML1310 (consolidation) were associated with a statistically higher incidence of NEC. We did not detect NEC episodes in patients treated with CPX-351, 5 + 2 (cytarabine, idarubicine), and high-dose cytarabine. Thus, we found that cytarabine could determine mucosal damage when associated with an anthracycline but not if delivered either alone or as dual-drug liposomal encapsulation of daunorubicin/cytarabine. We also describe NEC mortality, symptoms at diagnosis, intestinal sites involvement, and prognostic significance of bowel wall thickening.

Contrast-enhanced ultrasound in the assessment of Crohn's disease activity: comparison with computed tomography enterography

BACKGROUND AND OBJECTIVE

Continuous assessment of disease activity remains a huge challenge during the follow-ups of patients with Crohn's disease (CD). In this paper, we aimed to evaluate the performance of contrast-enhanced ultrasound (CEUS) by comparing with computed tomography enterography (CTE) in the assessment of disease activity in CD.

MATERIALS AND METHODS

Fifty-two patients diagnosed with CD were included in this study, using the CEUS and CTE as imaging methods for comparison. The selected parameters included the location and thickness of the thickest part of the intestinal wall, mesenteric fat proliferation, mesenteric vessels change, enhancement pattern and the presence of complications. Patients were clinically assessed using the Crohn's disease activity index (CDAI), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Simple endoscopic score for Crohn's disease (SES-CD) was regarded as the reference standard.

RESULTS

The location of the thickest part of the intestinal wall (κ = 0.653), bowel wall thickness (ICC = 0.795), mesenteric vessels change (κ = 0.692) and complications (κ = 0.796) displayed substantial agreement (0.61-0.80) between CEUS and CTE, while the detection of mesenteric fat proliferation (κ = 0.395) and enhancement pattern (κ = 0.288) showed fair consistency (0.21-0.40) for comparison. In CEUS, bowel wall thickness, mesenteric fat proliferation, enhancement pattern and mesenteric vessels change were statistically significant in assessing CD activity, while bowel wall thickness, mesenteric fat proliferation and mesenteric vessels change in CTE. Bowel wall thickness showed the best diagnostic performance in the assessment of CD activity at CEUS and CTE.

CONCLUSION

CEUS provides a radiation-free and effective way to assess the CD activity in comparison with CTE, which also avoids frequent colonoscopy examinations, improves tolerance of patients, and reduces the cost of medical care, thereby serving as a useful tool for CD follow-up.

Role of Multiparametric Intestinal Ultrasound in the Evaluation of Response to Biologic Therapy in Adults with Crohn's Disease

Crohn's disease is one of the two most common types of inflammatory bowel disease. Current medical therapies are based on the use of glucocorticoids, exclusive enteral nutrition, immunosuppressors such as azathioprine and methotrexate, and biological agents such as infliximab, adalimumab, vedolizumab, or ustekinumab. International guidelines suggest regular disease assessment and surveillance through objective instruments to adjust and personalize the therapy, reducing the overall rates of hospitalization and surgery. Although endoscopy represents the gold-standard for surveillance, its frequent use is strongly bordered by associated risks and costs. Consequently, alternative non-invasive tools to objectify disease activity and rule active inflammation out are emerging. Alongside laboratory exams and computed tomography or magnetic resonance enterography, intestinal ultrasonography (IUS) shows to be a valid choice to assess transmural inflammation and to detect transmural healing, defined as bowel wall thickness normalization, no hypervascularization, normal stratification, and no creeping fat. Compared to magnetic resonance imaging (MRI) or computed tomography, CT scan, IUS is cheaper and more widespread, with very similar accuracy. Furthermore, share wave elastography, color Doppler, and contrast-enhanced ultrasonography (CEUS) succeed in amplifying the capacity to determine the disease location, disease activity, and complications. This review aimed to discuss the role of standard and novel ultrasound techniques such as CEUS, SICUS, or share wave elastography in adults with Crohn's disease, mainly for therapeutic monitoring and follow-up.

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.

Early Diagnosis of Neutropenic Enterocolitis by Bedside Ultrasound in Hematological Malignancies: A Prospective Study

(1) Background: Neutropenic enterocolitis (NEC) is a life-threatening complication following chemotherapy with high mortality rates. Early diagnosis is crucial to improve outcomes. We designed a large prospective study employing bedside ultrasonography (US) as a novel approach to allow early diagnosis and prompt treatment to reduce mortality. (2) Methods: NEC was defined as US or computed tomography (CT)-proven bowel wall thickness ≥ 4 mm at the onset of at least one of the following symptoms: fever and/or abdominal pain and/or diarrhea during neutropenia. From 2007 to 2018, 1754 consecutive patients underwent baseline bedside US that was invariably repeated within 12 h from the onset of symptom(s) suggestive of NEC. (3) Results: Overall, 117 episodes of NEC were observed, and overall mortality was 9.4%. Bowel wall thickening was invariably absent in the negative control group. Abdominal pain associated with one or more symptoms correlated with the highest relative risk (17.33), sensitivity (89.7%), specificity (100%), and accuracy (96.2%) for diagnosis. The combination of abdominal pain and fever at onset significantly correlated with worse survival (p < 0.0001, OR 13.85). BWT (p = 0.046), type of therapy (p = 0.049) and blood culture positivity (p = 0.003) correlated with worse survival. (4) Conclusions: Bedside ultrasound is a non-invasive and radiation free imaging technique for early diagnosis of NEC and its prompt treatment significantly reduced mortality.

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, 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.

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.

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.

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.

Diagnostic performance of contrast-enhanced ultrasound for acute pyelonephritis in children

The objective of our study was to evaluate the performance of renal contrast-enhanced ultrasound (CEUS) against the 99m-labeled dimercaptosuccinic acid (DMSA) scan and computed tomography (CT) in children for the diagnosis of acute pyelonephritis. We included children who underwent both renal CEUS and the DMSA scan or CT. A total of 33 children (21 males and 12 females, mean age 26 ± 36 months) were included. Using the DMSA scan as the reference standard, the sensitivity, specificity, positive predictive value, and negative predictive value of CEUS was 86.8%, 71.4%, 80.5%, and 80.0%, respectively. When CT was used as the reference standard, the sensitivity, specificity, positive predictive value, and negative predictive value of CEUS was 87.5%, 80.0%, 87.5%, and 80.0%, respectively. The diagnostic accuracy of CEUS for the diagnosis of acute pyelonephritis was 80.3% and 84.6% compared to the DMSA scan and CT, respectively. Inter-observer (kappa = 0.54) and intra-observer agreement (kappa = 0.59) for renal CEUS was moderate. In conclusion, CEUS had good diagnostic accuracy for diagnosing acute pyelonephritis with moderate inter- and intra-observer agreement. As CEUS does not require radiation or sedation, it could play an important role in the future when diagnosing acute pyelonephritis in children.

Correlation between ultrasound consolidated score and simple endoscopic score for determining the activity of Crohn's disease

OBJECTIVES

The aim of this study was to develop an ultrasound consolidated score (UCS) in determining the activity of Crohn's disease (CD) and evaluate it with reference to simple endoscopic score (SES).

METHODS

From June 2014 to June 2017, 66 patients with CD were retrospectively enrolled in this study. Each patient underwent endoscopy and transabdominal ultrasound (US) examination. The morphological symmetry, echogenicity of bowel wall, bowel wall layer structure, echogenicity of peri-bowel fat, bowel wall thickness (BWT), and Limberg type on power Doppler US were assessed with transabdominal US, and an UCS scoring system was developed based on these characteristics. Endoscopic results were used as the reference standard and SES was calculated to determine the CD activity. Receiver operating characteristic curve analysis was performed to assess the diagnostic performance for determining CD activity and the correlation between UCS and SES was assessed using Spearman correlation analysis.

RESULTS

330 intestinal segments in 66 patients were included. The UCS of the segments in the remission phase ranged from 3.0 to 9.0 (mean, 3.6 ± 0.9) whereas in the active phase from 3.0 to 20.0 (mean, 10.6 ± 4.0) (p < 0.001). The cut-off value of UCS was 6. The associated area under ROC curve, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.980, 88.3%, 95.5%, 93.8%, 91.3%, and 92.3%, respectively. The correlation coefficient between UCS and SES was 0.90, which was higher than the correlation coefficient of 0.83 between BWT and SES.

CONCLUSIONS

The newly developed UCS with transabdominal US has a good performance and potentially provides an effective alternative for evaluating the activity of CD.

ADVANCES IN KNOWLEDGE

UCS is an effective method to evaluate the activity of CD because it provides comprehensive information of the disease. Therefore, it could be employed as an alternative for diagnosis of CD.

Imaging Inflammation and Infection in the Gastrointestinal Tract

A variety of seemingly non-specific symptoms manifest within the gastrointestinal (GI) tract, particularly in the colon, in response to inflammation, infection, or a combination thereof. Differentiation between symptom sources can often be achieved using various radiologic studies. Although it is not possible to provide a comprehensive survey of imaging gastrointestinal GI tract infections in a single article, the purpose of this review is to survey several topics on imaging of GI tract inflammation and infections. The review discusses such modalities as computed tomography, positron emission tomography, ultrasound, endoscopy, and magnetic resonance imaging while looking at up-an-coming technologies that could improve diagnoses and patient comfort. The discussion is accomplished through examining a combination of organ-based and organism-based approaches, with accompanying selected case examples. Specific focus is placed on the bacterial infections caused by Shigella spp., Escherichia coli, Clostridium difficile, Salmonella, and inflammatory conditions of diverticulitis and irritable bowel disease. These infectious and inflammatory diseases and their detection via molecular imaging will be compared including the appropriate differential diagnostic considerations.

Intestinal ultrasonography in adults with Crohn's disease: a 2020 update

In the last years intestinal ultrasonography (IUS) has increased its role in the management of inflammatory bowel diseases (IBD), that include Crohn's disease (CD) and ulcerative colitis. This is due to the fact that IUS is a non-invasive, inexpensive, and well-tolerated examination technique. Furthermore, it allows a real-time diagnosis with no radiation exposure. Usually, convex and linear probes with frequency between 3.5 and 12 MHz are used, also with the Color- Power Doppler. Focusing on CD, the IUS images of clinical interest are: bowel wall thickening (greater than 3 mm), pseudostratification and the wall vascularization. Moreover, IUS demonstrates inflammatory mass, loss of colonic haustration and the complications of the disease, such as stenosis, abscesses, and fistulas as well as other extraintestinal manifestations, such as lymph node enlargement and changes in the appearance of the mesenteric adipose tissue (creeping fat). Oral and intravenous contrast are used to obtain a better visualization of the bowel wall and to increase the diagnostic accuracy of IUS. In particular, intravenous contrast, administered during the procedure, allows to differentiate between active disease (bowel wall enhancement) and the fibrostenotic complications. Contrast-enhanced ultrasonography (CEUS) was proven to be useful in the follow-up and the disease recurrence detection. Beyond the support in the initial diagnosis, IUS has an important role in the follow-up of patients with CD, to monitor the response to the medical therapy and to detect possible complications. Furthermore, it can predict the recurrences after surgery, with more accuracy if Color-Doppler is used.

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.

Capillary Hemorrhage Induced by Contrast-Enhanced Diagnostic Ultrasound in Rat Intestine

Contrast-enhanced diagnostic ultrasound (CEDUS) can lead to microvascular injury and petechial hemorrhage by the cavitational mechanism of ultrasonic bioeffects. Capillary hemorrhage has been noted in the heart and kidney, which are common targets of CEDUS examination. CEDUS has also become useful for monitoring intestinal inflammation. In the 1990s, the risk of intestinal microvascular hemorrhage was investigated both for incidental exposure by lithotripter shockwaves and for contrast agent microbubbles acting as cavitation nuclei with laboratory pulsed ultrasound systems. This study was initiated to update the risk assessment for intestine exposed to diagnostic imaging simulating CEDUS. The abdomens of anesthetized rats were scanned by a 1.6 MHz phased array probe during infusion of microbubble suspensions simulating Definity ultrasound contrast agent. Dual image frames were triggered intermittently, and the output power was varied to assess the exposure response. Petechiae counts in small intestine mucosa and muscle layers increased with increasing trigger interval from 2 s to 10 s, indicative of a slow refill after microbubble destruction. The counts increased with increasing output above a threshold of 1.4 MPa peak rarefactional pressure amplitude. Petechiae were also seen in Peyer's patches, and occult blood was detected in many affected segments of intestine. These results are consistent with early laboratory pulsed-ultrasound results.

Therapeutic ultrasound attenuates DSS-induced colitis through the cholinergic anti-inflammatory pathway

BACKGROUND

Ulcerative Colitis (UC) is an Inflammatory Bowel Disease (IBD) characterized by uncontrolled immune response, diarrhoea, weight loss and bloody stools, where sustained remission is not currently achievable. Dextran Sulphate Sodium (DSS)-induced colitis is an animal model that closely mimics human UC. Ultrasound (US) has been shown to prevent experimental acute kidney injury through vagus nerve (VN) stimulation and activation of the cholinergic anti-inflammatory pathway (CAIP). Since IBD patients may present dysfunctional VN activity, our aim was to determine the effects of therapeutic ultrasound (TUS) in DSS-induced colitis.

METHODS

Acute colitis was induced by 2% DSS in drinking water for 7 days and TUS was administered to the abdominal area for 7 min/day from days 4-10. Clinical symptoms were analysed, and biological samples were collected for proteomics, macroscopic and microscopic analysis, flow cytometry and immunohistochemistry.

FINDINGS

TUS attenuated colitis by reducing clinical scores, colon shortening and histological damage, inducing proteomic tolerogenic response in the gut during the injury phase and early recovery of experimental colitis. TUS did not improve clinical and pathological outcomes in splenectomised mice, while α7nAChR (α7 nicotinic acetylcholine receptor - indicator of CAIP involvement) knockout animals presented with disease worsening. Increased levels of colonic F4/80+α7nAChR+ macrophages in wild type mice suggest CAIP activation.

INTERPRETATION

These results indicate TUS improved DSS-induced colitis through stimulation of the splenic nerve along with possible contribution by VN with CAIP activation. FUND: Intramural Research Programs of the Clinical Centre, the National Institute of Biomedical Imaging and Bioengineering at the NIH and CAPES/Brazil.

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.

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.

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.

Differentiation of Inflammatory From Fibrotic Ileal Strictures among Patients with Crohn's Disease Based on Visual Analysis: Feasibility Study Combining Conventional B-Mode Ultrasound, Contrast-Enhanced Ultrasound and Strain Elastography

The aim of this pilot study was to assess prospectively the feasibility of conventional B-mode ultrasound (US) and contrast-enhanced ultrasound (CEUS) combined with real-time strain elastography (SE) in the differentiation of inflammatory from fibrotic ileal strictures among patients with Crohn's disease (CD) based on visual analysis. Twenty non-consecutive patients (15 male and 5 female; mean age ± standard deviation, 40.2 ± 10.22 y) with CD and stricture of the terminal ileal loop were scanned by conventional B-mode US and CEUS and, subsequently, by real-time SE. Two independent readers visually classified each bowel stricture as fibrotic or inflammatory based on conventional B-mode US, CEUS, SE, individually and then for all techniques combined. All techniques combined had a higher (p <0.05) sensitivity (reader 1, 9/20 [45%]; reader 2, 7/20 [35%]), specificity (reader 1, 5/20 [25%]; reader 2, 8/20 [40%]) and diagnostic accuracy (reader 1, 14/20 [70%]; reader 2, 15/20 [75%]) and higher (p <0.05) area under the receiver operating characteristic curve (reader 1, 0.953; reader 2, 0.921) than individual techniques. Inter-reader agreement was fair for conventional B-mode US (k = 0.46) and CEUS (k = 0.39), moderate for SE (k = 0.6) and fair for all techniques combined (k = 0.38). Conventional B-mode US and CEUS, in combination with SE, may improve differentiation of inflammatory from fibrotic ileal strictures among patients with CD based on visual analysis.

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.

How to perform Contrast-Enhanced Ultrasound (CEUS)

"How to perform contrast-enhanced ultrasound (CEUS)" provides general advice on the use of ultrasound contrast agents (UCAs) for clinical decision-making and reviews technical parameters for optimal CEUS performance. CEUS techniques vary between centers, therefore, experts from EFSUMB, WFUMB and from the CEUS LI-RADS working group created a discussion forum to standardize the CEUS examination technique according to published evidence and best personal experience. The goal is to standardise the use and administration of UCAs to facilitate correct diagnoses and ultimately to improve the management and outcomes of patients.

Usefulness of Contrast-Enhanced Ultrasound in Differentiating Inflammatory Bowel Disease From Colon Cancer

To evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) in differential diagnosis of inflammatory bowel disease (IBD) and colon cancer, we enrolled 51 patients with thickened bowel walls (13 with IBD and 38 with colon cancer). Ultrasound and CEUS were performed and both qualitative and quantitative features were analyzed. The intestinal wall stratification was preserved in 63.6% of the IBD group but in only 2.6% of the colon cancer group (p <0.01). On CEUS, disordered enhancement and heterogeneous enhancement were shown in only 9.1% and 0%, respectively, of the IBD group while in 94.7% and 78.9%, respectively, of the colon cancer group (p <0.01). For quantitative analysis, compared to IBD, colon cancer showed later enhancement and slower wash-out with less speed to reach peak intensity (p <0.05). In conclusion, CEUS may prove useful for the differential diagnosis of IBD and colon cancer, but more studies are required.

Real-time elastography for the detection of fibrotic and inflammatory tissue in patients with stricturing Crohn's disease

PURPOSE

The distinction between active inflammation and fibrosis of the bowel wall is essential for therapeutic decisions in stricturing Crohn's disease. We aimed to assess whether real-time elastography (RTE) with strain ratio measurement could be useful in differentiating fibrotic from inflamed bowel strictures and to evaluate the possible relationship between US techniques and the histology of the stenotic bowel wall.

MATERIALS AND METHODS

Bowel ultrasonography (including RTE, color-Doppler and CEUS examination) was prospectively evaluated in 26 patients with symptomatic stricturing Crohn's disease, before surgery. RTE was adopted to evaluate bowel stiffness: five loops of 20 RTE frames were recorded for each stenotic segment and the mean strain ratio (MSR) was obtained. Histology scoring systems both for inflammation and fibrosis were established for surgical specimens.

RESULTS

No significant correlation was found between MSR and fibrosis score (P = 0.877). Color-Doppler score was significantly related to gut wall and submucosal thicknesses (P = 0.006 and P = 0.032, respectively). There was no significant correlation between the number of vessels counted at histology and color-Doppler and CEUS examinations (P = 0.170 and P = 0.302, respectively).

CONCLUSION

MSR detection was not able to distinguish fibrotic from inflammatory tissue in our selected population. This result could be influenced by the presence of the superimposed inflammation. Larger cohort of patients, further analysis with shear wave elastography, and validated histopathology classification systems for fibrosis and inflammation are necessary to assess if intestinal fibrosis could be reliably detected on the basis of bowel elastic properties.

Split-Bolus Injection Producing Simultaneous Late Arterial and Portal Venous Phases in CT Enterography: Preliminary Results

OBJECTIVE

The purpose of this article is to evaluate the image quality and added value of split-bolus contrast agent injection combining late arterial and portal venous phases compared with single-bolus contrast agent injection late arterial phase CT enterography.

MATERIALS AND METHODS

Consecutive patients who underwent CT enterography before and after implementation of a single-bolus CT enterography protocol were included. Attenuation and contrast-to-noise ratio (CNR) were assessed by ROI measurements of the bowel wall and arterial and venous structures. Subjective enhancement of the bowel wall (1, arterial; 2, mucosal; 3, transmural; 4, transmural with mucosal hyperenhancement) and bowel abnormalities were assessed by two independent readers. MR enterography examinations, endoscopy reports, and surgery reports within 30 days after CT enterography were used to produce a composite outcome.

RESULTS

Sixty-six patients were included in our study: 33 (mean [± SD] age, 46.0 ± 19.8 years) who underwent split-bolus CT enterography and 33 (mean age, 49.9 ± 19.0 years) who underwent single-bolus CT enterography. Bowel wall attenuation and CNR were higher for split-bolus CT enterography than for single-bolus CT enterography at 120 kVp (enhancement, 98.7 ± 23.1 HU vs 85.1 ± 23.3 HU; CNR, 6.4 ± 2.5 vs 4.4 ± 2.3; p < 0.01). Subjective ratings of bowel wall enhancement were higher with the split-bolus CT enterography than the single-bolus CT enterography (2.6 ± 0.8 vs 2.3 ± 0.6; p < 0.001). Split-bolus CT enterography led to a higher detection rate of mucosal hyperenhancement than did single-bolus CT enterography in patients with active inflammatory bowel disease (100.0% [7/7; 95% CI, 59.0-100.0%] vs 33.3% [2/6; 95% CI, 4.3-77.7%]; p = 0.02), whereas both protocols had a specificity of 100.0% (9/9).

CONCLUSION

Split-bolus CT enterography led to improved CNR (47%) compared with single-bolus CT enterography and significantly increased the detection rate of mucosal hyperenhancement in patients with active inflammatory bowel disease.

Role of Bowel Ultrasound in the Diagnosis and Follow-up of Patients with Crohn's Disease

Crohn's disease (CD) is an inflammatory chronic bowel disorder; it can involve the whole gastrointestinal tract, but its localization in the ileum or colon is most common. The reference standard for the diagnosis of CD is ileocolonoscopy with histologic assessment. The reference standard for the detection of any complications is surgery. However, imaging techniques have an important role both in the detection/localization of CD and in the follow-up of CD patients. In the last few years, the technical development of ultrasound equipment, the advent of new technologies such as elastography and mostly the increased expertise of sonographers have boosted the role of bowel ultrasound in assessment of the gastrointestinal tract. In fact, bowel ultrasound is particularly attractive thanks to its widespread availability, non-invasiveness, low cost and good reproducibility, as it can be easily repeated during follow-up. The aim of this article is to provide an extensive overview of the actual role of bowel ultrasound in the detection and follow-up of patients with CD.

SICUS and CEUS imaging in Crohn's disease: an update

Endoscopy remains the main technique in the diagnosis and treatment of Crohn's disease (CD); nevertheless, the recent development of innovative and non-invasive imaging techniques has led to a new tool in the exploration of small bowel in CD patients. This paper reviews the available data on ultrasound imaging used for the evaluation of CD, highlighting the role of small intestine contrast-enhanced ultrasonography with the use of oral and intravenous contrast agents.

Dynamic contrast-enhanced ultrasound of the bowel wall with quantitative assessment of Crohn's disease activity in childhood

Background

Contrast-enhanced ultrasound (CEUS) has become an established non-invasive, patient-friendly imaging technique which improves the characterization of lesions. In addition, dynamic contrast-enhanced ultrasound (DCE-US) provides valuable information concerning perfusion of examined organs. This review addresses current applications of CEUS in children, focused on DCE-US of the bowel wall in patients with Crohn disease, which enables realtime assessment of the bowel wall vascularity with semi-quantitative and quantitative assessment of disease activity and response to medical treatment.

Conclusions

Crohn’s disease is a chronic inflammatory relapsing disease. Frequent imaging re-evaluation is necessary. Therefore, imaging should be as little invasive as possible, children friendly with high diagnostic accuracy. US with wide varieties of techniques, including CEUS/DCE-US, can provide an important contribution for diagnosing and monitoring a disease activity. Even if the use of US contrast agent is off-label in children, it is welcome and widely accepted for intravesical use, and a little less for intravenous use, manly in evaluation of parenchymal lesions. To our knowledge this is the first time that the use of DCE-US in the evaluation of activity of small bowel Crohn disease with quantitative assessment of kinetic parameters is being described in children. Even if the results of the value and accuracy of different quantitative kinetic parameters in published studies in adult population often contradict one another there is a great potential of DCE-US to become a part of the entire sonographic evaluation not only in adults, but also in children. Further control studies should be performed.

Abdominal ultrasonography of the pediatric gastrointestinal tract

Ultrasound is an invaluable imaging modality in the evaluation of pediatric gastrointestinal pathology; it can provide real-time evaluation of the bowel without the need for sedation or intravenous contrast. Recent improvements in ultrasound technique can be utilized to improve detection of bowel pathology in children: Higher resolution probes, color Doppler, harmonic and panoramic imaging are excellent tools in this setting. Graded compression and cine clips provide dynamic information and oral and intravenous contrast agents aid in detection of bowel wall pathology. Ultrasound of the bowel in children is typically a targeted exam; common indications include evaluation for appendicitis, pyloric stenosis and intussusception. Bowel abnormalities that are detected prenatally can be evaluated after birth with ultrasound. Likewise, acquired conditions such as bowel hematoma, bowel infections and hernias can be detected with ultrasound. Rare bowel neoplasms, vascular disorders and foreign bodies may first be detected with sonography, as well. At some centers, comprehensive exams of the gastrointestinal tract are performed on children with inflammatory bowel disease and celiac disease to evaluate for disease activity or to confirm the diagnosis. The goal of this article is to review up-to-date imaging techniques, normal sonographic anatomy, and characteristic sonographic features of common and uncommon disorders affecting the gastrointestinal tract in children.

Imaging patients with renal impairment

Imaging with intravascular contrast media is generally considered safe, particularly in patients without renal failure. However, as renal function deteriorates, the potential risk of nonallergic-type adverse events increases. This presents a unique challenge, particularly when the use of intravenous contrast media is deemed essential for diagnostic purposes. Following a discussion regarding the definition and epidemiology of kidney injury, this review focuses on the evolving understanding of both contrast-induced nephropathy and nephrogenic systemic fibrosis and discusses preventative strategies aimed at minimizing the risk of developing these entities. Alternative non-contrast imaging techniques are also discussed.

Particularities of Crohn's disease in pediatric patients: current status and perspectives regarding imaging modalities

A consensus on the best imaging modality evaluating inflammatory bowel disease in the pediatric population is lacking and it is often unclear which modality to choose in specific clinical circumstances. Children with inflammatory bowel disease are exposed to ionizing radiation from multiple imaging studies performed at initial diagnosis, throughout treatment and during the follow-up period. This paper discusses the value of different imaging techniques in pediatric patients with inflammatory bowel disease and gives a review of the literature. In addition, particular features of inflammatory bowel disease in children including the predilection of affected segments in the gastrointestinal tract are highlighted. Based on current literature knowledge, we encourage an integrative approach to the interpretation of clinical and imaging data for diagnosis and follow-up in daily clinical settings.

Ultrasonography in gastroenterology

Ultrasonography (US) is a safe and available real-time, high-resolution imaging method, which during the last decades has been increasingly integrated as a clinical tool in gastroenterology. New US applications have emerged with enforced data software and new technical solutions, including strain evaluation, three-dimensional imaging and use of ultrasound contrast agents. Specific gastroenterologic applications have been developed by combining US with other diagnostic or therapeutic methods, such as endoscopy, manometry, puncture needles, diathermy and stents. US provides detailed structural information about visceral organs without hazard to the patients and can play an important clinical role by reducing the need for invasive procedures. This paper presents different aspects of US in gastroenterology, with a special emphasis on the contribution from Nordic scientists in developing clinical applications.

Growing indications for CEUS: The kidney, testis, lymph nodes, thyroid, prostate, and small bowel

Contrast enhanced ultrasonography (CEUS) is increasingly used for non-hepatic applications as well, so that nearly all organs have been investigated. Among them, there is a growing clinical use for a variety of pathologies of the kidney, testis, and small bowel. The possibility to differentiate benign from malignant nodes in cancer patients has been investigated. A new application is in the detection of sentinel nodes after intradermal microbubble injection. The need to distinguish thyroid nodules eligible for fine needle aspiration cytology has led to the use of CEUS in thyroid examinations as well. The potential of CEUS for prostate cancer detection has been extensively investigated, with encouraging initial results. Early promise, however, has not been fulfilled. New perspective regards evaluation of the extent of prostate tissue devascularization following ablative treatments.

Ultrasonographic imaging of inflammatory bowel disease in pediatric patients

Inflammatory bowel disease (IBD) is one of the most common chronic gastrointestinal diseases in pediatric patients. Choosing the optimal imaging modality for the assessment of gastrointestinal disease in pediatric patients can be challenging. The invasiveness and patient acceptance, the radiation exposure and the quality performance of the diagnostic test need to be considered. By reviewing the literature regarding imaging in inflammatory bowel disease the value of ultrasound in the clinical management of pediatric patients is highlighted. Transabdominal ultrasound is a useful, noninvasive method for the initial diagnosis of IBD in children; it also provides guidance for therapeutic decisions and helps to characterize and predict the course of the disease in individual patients. Ultrasound techniques including color Doppler imaging and contrast-enhanced ultrasound are promising imaging tools to determine disease activity and complications. Comparative studies between different imaging methods are needed.

Bowel perfusion measured with dynamic contrast-enhanced ultrasound predicts treatment outcome in patients with Crohn's disease

BACKGROUND

To improve management of patients with Crohn's disease (CD), objective measurements of the degree of local inflammation in the gastrointestinal wall are needed. Increased microvessel density and perfusion are typical features of acute inflammation and can be estimated with contrast-enhanced ultrasound (CEUS). The aim of the study was to investigate whether CEUS can provide prognostic information about patients treated medically for an acute exacerbation of CD.

METHODS

Fourteen patients with CD who received medical treatment for acute exacerbation with systemic steroids or tumor necrosis factor-α inhibitors were prospectively recruited. The patients were examined with clinical scoring, blood tests, and CEUS at time 0, 1, 3, and 12 months after initiation of the treatment. Outcome was treatment efficacy or treatment failure defined as change in medical treatment after 1 month or later. The perfusion analysis was performed with a commercially available software program that analyzes the contrast intensity in a selected area, fits the data to a standardized time-intensity curve, and derives several relative perfusion parameters.

RESULTS

Six of the 14 patients had treatment failure during the study period. There was a significant difference between the groups for peak contrast enhancement (P = 0.013), rate of wash-in (P = 0.020) and wash-out (P = 0.008), and the area under the time-intensity curve in the wash-in phase (0.013) at the examination 1 month after the start of treatment.

CONCLUSIONS

Perfusion analysis of the intestinal wall with CEUS 1 month after starting treatment in patients with CD can provide prognostic information regarding treatment efficacy.

Ultrasonographic findings in Crohn's disease

In recent years transabdominal bowel sonography has become a first-line modality both in the diagnosis and in the follow-up of inflammatory bowel diseases, especially Crohn's disease, reaching values of sensitivity ranging from 84 to 93 %. In particular, its role is very useful in the early diagnosis of complications such as stenosis, phlegmons, abscesses and fistulae. According to the available literature the ability of US to provide information about disease activity is still under debate and further studies are necessary. In this regard, of fundamental importance is the use of additional techniques such as color- and power-Doppler and contrast-enhanced ultrasound. The purpose of this paper is to report the main sonographic intestinal and extraintestinal findings detectable in Crohn's disease.

Contrast-enhanced ultrasound of the small bowel in Crohn's disease

Crohn's disease (CD) is a chronic transmural inflammatory disease of the gastrointestinal tract characterized by episodes of inflammation alternating with periods of remission. Unenhanced grey-scale ultrasound may evaluate the localisation and the length of the affected intestinal segments and may detect transmural complications, including fistulas, abscesses and phlegmons, but it is less accurate to assess the CD activity. Contrast-enhanced ultrasound has become an important imaging modality in patients with CD for the grading of disease activity, the differentiation between small bowel stricture due to inflammation or mural fibrosis, and for the assessment of the response to specific therapy. New dedicated software packages allow the accurate quantification of the enhancement within the small bowel wall after microbubble contrast agent injection to obtain different kinetic semi-quantitative parameters-the percentage of the maximal enhancement, the time-to-the peak enhancement, and the area under the time-intensity curve-which are very useful to differentiate the inflammatory oedema from fibrosis and to differentiate responders from non-responders to the specific therapy among patients with CD.

Quantitative analysis of contrast-enhanced ultrasonography of the bowel wall can predict disease activity in inflammatory bowel disease

PURPOSE

To evaluate the accuracy of quantitative analysis of bowel wall enhancement in inflammatory bowel disease (IBD) with contrast enhanced ultrasound (CEUS) by comparing the results with vascular density in a biopsy sample from the same area of the intestinal tract, and to determine the usefulness of this analysis for the prediction of disease activity.

MATERIALS AND METHODS

This prospective study was approved by our institute's ethics committee and all patients gave written informed consent. We enrolled 33 consecutive adult patients undergoing colonoscopy and biopsy for IBD. All patients underwent CEUS and the results were quantitatively analyzed. Vessel count per high-power field on biopsy specimens was compared with colonoscopy, baseline ultrasonography, and CEUS findings, and with analysis of peak intensity, time to peak, regional blood volume, mean transit time, and regional blood flow. Results in patients with high and low vascular density were compared using Fisher's test, t-test, Pearson's correlation test, and receiver operating characteristic curve (ROC) analysis. Cutoff values were determined using ROC analysis, and sensitivity and specificity were calculated.

RESULTS

High vascular density (>265 vessels per field) on histological examination was significantly correlated with active disease on colonoscopy, baseline ultrasonography, and CEUS (p<.0001). Quantitative analysis showed a higher enhancement peak, a shorter time to peak enhancement, a higher regional blood flow and regional blood volume in patients with high vascular density than in those with low vascular density. Cutoff values to distinguish between active and inactive disease were identified for peak enhancement (>40.5%), and regional blood flow (>54.8 ml/min).

CONCLUSION

Quantitative analysis of CEUS data correlates with disease activity as determined by vascular density. Quantitative parameters of CEUS can be used to predict active disease with high sensitivity and specificity.

Contrast-enhanced ultrasonography for the determination of Crohn's disease activity - preliminary experience

Background

Contrast-enhanced ultrasound (CEUS) is a recent non-invasive modality, which may partially replace currently used techniques (endoscopy, CT enterography and MR enterography) in the diagnostics and assessment of Crohn’s disease (CD). The aim of the study was to analyze early experience in the use of CEUS for the measurement of activity and staging of CD.

Material/Methods

Eleven patients previously diagnosed with CD were included in the study. They underwent contrast-enhanced ultrasonography (SonoVue, Bracco), low-dose CT enterography (LDCTE), assessment of laboratory markers of inflammation and clinical CD activity index (CDAI). Contrast enhancement was evaluated using a semi-quantitative method and a quantitative method that included measurement of peak enhancement (PE), enhancement curve rise time (RT) and wash-in-rate (WiR).

Results

Ileal wall thickening was observed in all patients. Semi-quantitative method was used to observe CD activity in CEUS in 10 cases that perfectly matched LDCTE findings. There was a moderate positive correlation between PE and CDAI (r=0.65, p<0.001). There was no significant relationship between perfusion parameters and laboratory markers of inflammation.

Conclusions

CEUS is a promising modality for non-invasive assessment of pathologic ileal vascularization in the course of Crohn’s disease. Intensity of enhancement in CEUS reflects activity of the disease detected in LDCTE and correlates with CDAI.