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

Ultrasound innovations in abdominal radiology: techniques and clinical applications in pediatric imaging

Contrast-enhanced ultrasound, microvascular imaging, elastography, and fat quantification have varying degrees of utility, with some applications in the pediatric setting mirroring that in adults and having unique uses when applied to children in others. This review will present novel ultrasound technologies and the clinical context in which they are applied to the pediatric abdomen. New ultrasound technologies have a broad range of applications in clinical practice and represent a powerful diagnostic tool with the potential to replace other imaging modalities, such as magnetic resonance imaging and computed tomography, in specific cases.

Contrast-Enhanced Ultrasonography for the Evaluation of Crohn's Disease in Pediatric Patients

BACKGROUND

Contrast-enhanced ultrasonography (CEUS) of the bowel wall has been suggested as an alternative imaging modality for the follow-up of children with Crohn's disease. To demonstrate the feasibility and clinical usefulness of CEUS in the estimation of Crohn's disease activity in children with endoscopy as the reference standard.

METHOD

In this prospective study, 30 pediatric patients with Crohn's disease (24 males and 6 females; median age 14 years) underwent CEUS from December 2020 to August 2021. The simple endoscopic score for Crohn's disease, pediatric Crohn's disease activity index, serologic inflammatory markers, fecal calprotectin and CEUS perfusion parameters were assessed and compared between the inactive and active group based on endoscopic findings.

RESULTS

CEUS was performed successfully in all 30 patients. Two patients showed mild adverse side effects such as temporary dysosmia. The active Crohn's disease group showed higher erythrocyte sedimentation rate (mm/hr) (13.0 vs. 2.0, P = 0.003), C-reactive protein (mg/dL) (4.7 vs. 0.55, P = 0.018) and fecal calprotectin (mcg/g) (1,503 vs. 237.5, P = 0.005). Among the quantitative parameters for CEUS, the mean gradient to the peak value was higher in the active group (1.18 vs. 0.93, P = 0.034). The sensitivity and specificity of the mean gradient to the peak value for predicting active Crohn's disease was 55.6% and 83.3%, respectively, with a cut-off of 1.09 (P = 0.015).

CONCLUSION

CEUS can be a safe and specific diagnostic modality for Crohn's disease activity in children. Among quantitative CEUS parameters, the mean gradient to the peak value could be used to differentiate active and inactive Crohn's disease.

The Utility of Contrast Enhanced Ultrasound and Elastography in the Early Detection of Fibro-Stenotic Ileal Strictures in Children with Crohn's Disease

Purpose

Crohn's disease (CD) is a chronic, idiopathic bowel disorder that can progress to partial or complete bowel obstruction. At present, there are no reliable diagnostic tests that can readily distinguish between acute inflammatory, purely fibrotic and mixed inflammatory and fibrotic. Our aim is to study the utility of contrast enhanced ultrasound (CEUS) in combination with shear wave elastography (SWE) to differentiate fibrotic from inflammatory strictures in children with obstructive CD of the terminal ileum.

Methods

Twenty-five (19 male) children between 2016-2021 with CD of the terminal ileum were recruited into the study. Among these patients, 22 had CEUS kinetic measurements of tissue perfusion, including wash-in slope (dB/sec), peak intensity (dB), time to peak intensity (sec), area under the curve (AUC) (dB sec), and SWE. In total, 11 patients required surgery due to bowel obstruction. Histopathologic analysis was performed by a pathologist who was blinded to the CEUS and SWE test results.

Results

Patients that underwent surgical resection had significantly higher mean area under the curve on CEUS compared to patients responsive to medical therapy (p=0.03). The AUC also correlated with the degree of hypertrophy and the percent fibrosis of the muscularis propria, as determined by histopathologic grading (p<0.01). There was no difference in the mean elastography measurements between these two patient groups.

Conclusion

CEUS is a useful radiological technique that can help identify pediatric patients with medically refractory obstructive fibrotic strictures of the terminal ileum that should be considered for early surgical resection.

The comparison between contrast-enhanced ultrasound and contrast-enhanced magnetic resonance imaging in diagnosing bladder urothelial carcinoma

PURPOSE

The surgical treatment of bladder urothelial carcinoma depends on whether the tumor has invaded the bladder muscular layer. Normal ultrasound and contrast-enhanced magnetic resonance imaging (contrast-enhanced MRI) are widely used in patients bear bladder tumors; the latter is also widely used in estimating the muscularis invasion of bladder cancer (BC). However, contrast-enhanced ultrasound (CEUS) is rarely used in this aspect. As the gold standard in diagnosing muscularis invasion remains being pathological examination, this study was set to find out whether there are differences between CEUS and contrast-enhanced MRI in diagnosing bladder malignant tumors and in diagnosing the muscularis invasion of the bladder urothelial carcinoma under the guide of the pathological results.

METHODS

160 patients from Yongchuan Hospital of Chongqing Medical University and The Second Affiliated Hospital of Chongqing Medical University were recruited from July 1st, 2021, to June 30th, 2022. Patients are arranged to undergo CEUS, contrast-enhanced MRI and then take a surgery. After surgery, we compare the results of CEUS, MRI and the pathological results, using software to run the statistical examinations.

RESULTS

The accuracies of CEUS and contrast-enhanced MRI in diagnosing malignant bladder tumors were 85.90 and 84.62%, and they had no differences (P > 0.05). While the accuracies of CEUS and contrast-enhanced MRI in diagnosing the muscularis invasion were 84.62 and 76.92%, in which CEUS had a better sensitivity (P < 0.05).

CONCLUSIONS

We found that CEUS and contrast-enhanced MRI had no differences in diagnosing the different pathological types (benign or malignant) of BC, but CEUS holds a better sensitivity in diagnosing muscularis invasions of bladder urothelial carcinoma than the contrast-enhanced MRI.

Non-Invasive Diagnosis of Pediatric Intestinal Graft-Versus-Host Disease: A Case Series

Intestinal graft-versus-host disease (I-GvHD) represents a life-threatening complication in allogeneic stem cell transplantation (SCT). Unfortunately, non-invasive validated diagnostic tools to diagnose I-GvHD, evaluate treatment response, and guide the duration of immunosuppression are still lacking. We employed standard ultrasound and power Doppler to diagnose and follow up on pediatric intestinal GvHD. We herein report on three patients, prospectively evaluated among 24 pediatric patients referred to our center for allogeneic SCT. These three patients presented abdominal pain and diarrhea within the first 200 days after transplantation. In the reported cases, we performed small- and large-intestine ultrasound (US) at clinical onset of lower-intestinal symptoms and, when intestinal GvHD was confirmed, at GvHD flares, if any, and at follow-up. US constantly (3/3 patients) revealed increased bowel wall thickening (BWT) with different bowel segments’ involvement from patient to patient. Further, a moderate or strong increased Doppler signaling was seen in 2 out of 3 patients, according to clinical GVHD staging (e.g., the more the increase, the more the staging). Standard sonography corroborated GvHD diagnosis in all patients considered and was able to detect GvHD progression or complete normalization of findings, thus simplifying ensuing clinical decisions. Our report highlights the need to design clinical trials for the validation of non-invasive radiologic tools for diagnosis and follow-up of GvHD, especially in pediatric patients.

Translational research in pediatric contrast-enhanced ultrasound

The role of contrast-enhanced ultrasound (CEUS) imaging is being widely explored by various groups for its use in the pediatric population. Clinical implementation of new diagnostic or therapeutic techniques requires extensive and meticulous preclinical testing and evaluation. The impact of CEUS will be determined in part by the extent to which studies are oriented specifically toward a pediatric population. Rather than simply applying principles and techniques used in the adult population, these studies are expected to advance and augment preexisting knowledge with pediatric-specific information. To further develop this imaging modality for use in children, pediatric-focused preclinical research is essential. In this paper we describe the development and implementation of the pediatric-specific preclinical animal and phantom models that are being used to evaluate CEUS with the goal of clinical translation to children.

European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB): An Update on the Pediatric CEUS Registry on Behalf of the "EFSUMB Pediatric CEUS Registry Working Group"

The European Federation of Ultrasound in Medicine and Biology (EFSUMB) created the "EFSUMB Pediatric Registry" (EFSUMB EPR) with the purpose of collecting data regarding the intravenous application of pediatric contrast-enhanced ultrasound (CEUS). The primary aim was to document the current clinical practice and usefulness of the technique and secondarily to assess CEUS safety in children. We issue the preliminary results of this database and examine the overall practice of CEUS in children in Europe.

Contrast-enhanced ultrasonography in the evaluation of Crohn disease activity in children: comparison with histopathology

BACKGROUND

Contrast-enhanced ultrasound (US) of the bowel wall has been suggested as an alternative imaging modality for the follow-up of children with Crohn disease.

OBJECTIVE

To evaluate the diagnostic performance of contrast-enhanced US in the estimation of Crohn disease activity in children with histopathology as the reference standard.

MATERIALS AND METHODS

In 24 children with Crohn disease confirmed on histopathology, disease activity was evaluated on 40 bowel segments using US score and subjective and quantitative contrast-enhanced US evaluation. Contrast-enhanced US evaluation included enhancement pattern analysis with a graphic representation of log time-intensity curve and calculation of kinetic parameters with the definition of thresholds for disease activity, as determined by receiver operating characteristics curve analysis. The diagnostic accuracy of US with colour Doppler imaging and subjective and quantitative contrast-enhanced US were calculated.

RESULTS

Moderate or severe inflammation was identified in 18 segments and remission or mild inflammation was identified in 22 segments on histopathology. The quantitative contrast-enhanced US, namely the peak enhancement value, had 72.2% sensitivity (95% confidence interval [CI] 46.5-90.3), 100% specificity (95% CI 84.6-100.0) and 87.5% diagnostic accuracy (95% CI 73.2-95.8) in predicting moderate or severe grade inflammation at histopathology. The sensitivity, specificity and diagnostic accuracy of subjective contrast-enhanced US were 77.8% (95% CI 52.4-93.6), 77.3% (95% CI 54.6-92.2) and 77.5% (95% CI 61.6-89.2), respectively, and of US with colour Doppler imaging were 55.6% (95% CI 30.8-78.5), 86.4% (95% CI 65.1-79.1) and 72.5% (95% CI 56.1-85.4), respectively.

CONCLUSION

Quantitative contrast-enhanced US has the potential of becoming a complementary method in the evaluation of Crohn disease activity in children. Fibrosis may affect peak enhancement results and underestimate inflammatory 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.

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.

Contrast-Enhanced Ultrasound and Shear Wave Elastography Evaluation of Crohn's Disease Activity in Three Adolescent Patients

Characterizing inflammation and fibrosis in Crohn's disease (CD) is necessary to guide clinical management, but distinguishing the two remains challenging. Novel ultrasound (US) techniques: contrast-enhanced US (CEUS) and shear wave elastography (SWE) offer great potential in evaluating disease activity in pediatric patients. Three patients ages 16 to 20 with known CD underwent CEUS and SWE to characterize bowel wall inflammation and fibrosis. Magnetic resonance enterography, endoscopy, or surgical pathology findings are also described when available. The patients' disease activity included acute inflammation, chronic inflammation with stricture formation, and a fibrotic surgical anastomosis without inflammation. CEUS was useful in determining the degree of inflammation, and SWE identified bowel wall fibrosis. Used together these techniques allow for better characterization of the degree of fibrosis and inflammation in bowel strictures. With further validation CEUS and SWE may allow for improved characterization of bowel strictures and disease flares in pediatric patients suffering from CD.

Applications of contrast-enhanced ultrasound in the pediatric abdomen

Contrast-enhanced ultrasound (CEUS) is a radiation-free, safe, and in specific clinical settings, highly sensitive imaging modality. Over the recent decades, there is cumulating experience and a large volume of published safety and efficacy data on pediatric CEUS applications. Many of these applications have been directly translated from adults, while others are unique to the pediatric population. The most frequently reported intravenous abdominal applications of CEUS in children are the characterization of focal liver lesions, monitoring of solid abdominal tumor response to treatment, and the evaluation of intra-abdominal parenchymal injuries in selected cases of blunt abdominal trauma. The intravesical CEUS application, namely contrast-enhanced voiding urosonography (ceVUS), is a well-established, pediatric-specific imaging technique entailing the intravesical administration of ultrasound contrast agents for detection and grading of vesicoureteral reflux. In Europe, all pediatric CEUS applications remain off-label. In 2016, the United States Food and Drug Administration (FDA) approved the most commonly used worldwide second-generation ultrasound contrast SonoVue®/Lumason® for pediatric liver and intravesical applications, giving new impetus to pediatric CEUS worldwide.

Anatomical Road Mapping Using CT and MR Enterography for Ultrasound Molecular Imaging of Small Bowel Inflammation in Swine

OBJECTIVES

To evaluate the feasibility and time saving of fusing CT and MR enterography with ultrasound for ultrasound molecular imaging (USMI) of inflammation in an acute small bowel inflammation of swine.

METHODS

Nine swine with ileitis were scanned with either CT (n = 3) or MR (n = 6) enterography. Imaging times to load CT/MR images onto a clinical ultrasound machine, fuse them to ultrasound with an anatomical landmark-based approach, and identify ileitis were compared to the imaging times without anatomical road mapping. Inflammation was then assessed by USMI using dual selectin-targeted (MB_Selectin) and control (MB_Control) contrast agents in diseased and healthy control bowel segments, followed by ex vivo histology.

RESULTS

Cross-sectional image fusion with ultrasound was feasible with an alignment error of 13.9 ± 9.7 mm. Anatomical road mapping significantly reduced (P < 0.001) scanning times by 40%. Localising ileitis was achieved within 1.0 min. Subsequently performed USMI demonstrated significantly (P < 0.001) higher imaging signal using MB_Selectin compared to MB_Control and histology confirmed a significantly higher inflammation score (P = 0.006) and P- and E-selectin expression (P ≤ 0.02) in inflamed vs. healthy bowel.

CONCLUSIONS

Fusion of CT and MR enterography data sets with ultrasound in real time is feasible and allows rapid anatomical localisation of ileitis for subsequent quantification of inflammation using USMI.

KEY POINTS

• Real-time fusion of CT/MRI with ultrasound to localise ileitis is feasible. • Anatomical road mapping using CT/MRI significantly decreases the scanning time for USMI. • USMI allows quantification of inflammation in swine, verified with ex vivo histology.

Inflammatory bowel diseases: a burden in pediatrics: Case series and a review of the literature

INTRODUCTION

Inflammatory bowel disease is a chronic condition of the gastrointestinal tract, comprising mainly Crohn disease (CD) and ulcerative colitis (UC). Both of them are frequently encountered in children, being multifactorial conditions, with an unclear etiology.

PATIENTS CONCERNS

We present 4 cases of inflammatory bowel disease (IBD) in children in order to underline the variable evolution depending on the patient's particularities.

DIAGNOSIS, INTERVENTIONS AND OUTCOMES

The first case, a 13-year-old male patient, with a history of Henoch-Schonlein purpura, was admitted for rectal bleeding and weight loss, with normal laboratory parameters. The colonoscopy and the histopathological examination established the diagnosis of UC. The evolution was initially favorable under corticosteroids and sulfasalazine, but with 3 relapses in 2 years. The second case, a 16-year-old male patient, with a history of lactose intolerance and constipation, was admitted for bloody, diarrheic stools, the laboratory tests pointing out only leukocytosis with neutrophilia. The colonoscopy and histopathological examination established the diagnosis of UC. The patient's evolution was slowly favorable. The third case, a 9-year old male patient, with emotional disorders and babbling, admitted for semiconsistent, bloody stools, with increased inflammatory tests, whose colonoscopy pointed out diffuse edema and hemorrhages, the histopathological examination establishing the diagnosis of CD. The evolution was initially favorable, but with 5 relapses in 3 years. The last case, a 12-year-old male patient, was admitted with diarrheic, bloody stools, refractory to antibiotics, and weight loss, with increased inflammatory tests. The colonoscopy pointed out ulcerations, hemorrhages, and disseminated puss deposits. The histopathological examination established the diagnosis of CD. The patient's evolution was favorable, with only 1 relapse in 3 years.

CONCLUSIONS

The adequate management, especially the self-management can influence the prognosis of patients with IBD, even though it is unpredictable and burdened by the risk of malignant transformation.