Bowel Ultrasonography in Inflammatory Bowel Disease

Automatized Detection of Crohn's Disease in Intestinal Ultrasound Using Convolutional Neural Network

INTRODUCTION

The use of intestinal ultrasound (IUS) for the diagnosis and follow-up of inflammatory bowel disease is steadily growing. Although access to educational platforms of IUS is feasible, novice ultrasound operators lack experience in performing and interpreting IUS. An artificial intelligence (AI)-based operator supporting system that automatically detects bowel wall inflammation may simplify the use of IUS by less experienced operators. Our aim was to develop and validate an artificial intelligence module that can distinguish bowel wall thickening (a surrogate of bowel inflammation) from normal bowel images of IUS.

METHODS

We used a self-collected image data set to develop and validate a convolutional neural network module that can distinguish bowel wall thickening >3 mm (a surrogate of bowel inflammation) from normal bowel images of IUS.

RESULTS

The data set consisted of 1008 images, distributed uniformly (50% normal images, 50% abnormal images). Execution of the training phase and the classification phase was performed using 805 and 203 images, respectively. The overall accuracy, sensitivity, and specificity for detection of bowel wall thickening were 90.1%, 86.4%, and 94%, respectively. The network exhibited an average area under the ROC curve of 0.9777 for this task.

CONCLUSIONS

We developed a machine-learning module based on a pretrained convolutional neural network that is highly accurate in the recognition of bowel wall thickening on intestinal ultrasound images in Crohn's disease. Incorporation of convolutional neural network to IUS may facilitate the use of IUS by inexperienced operators and allow automatized detection of bowel inflammation and standardization of IUS imaging interpretation.

Comparative study between bowel ultrasound and magnetic resonance enterography among Egyptian inflammatory bowel disease patients

BACKGROUND

Bowel ultrasound and magnetic resonance enterography (MRE) are decisive medical imaging modalities for diagnosing and locating bowel lesions with its extramural extent and complications. They assess the degree of activity, help clinicians to identify patients in need of surgery, and can be used for patient follow-up.

AIM

To compare the role of MRE and bowel ultrasound in diagnosis and follow-up of inflammatory bowel disease (IBD) patients in Egypt.

METHODS

The study was conducted on 40 patients with IBD. All patients were subjected to clinical assessment, laboratory investigations, bowel ultrasound, MRE, and colonoscopy up to the terminal ileum with biopsies for histopathological examination.

RESULTS

This study was conducted on 14 patients (35%) with ulcerative colitis and 26 patients (65%) with Crohn's disease; 34 (85%) of these patients had active disease. Bowel ultrasound detected different bowel lesions with the following accuracies: ileum (85%), large bowel (70%), fistula (95%), stricture and proximal dilatation (95%) and abscesses (100%). Also, it showed that statistically significance of bowel ultrasound in differentiation between remission and activity of IBD in comparison to MRE and colonoscopy.

CONCLUSION

In comparison to MRE, bowel ultrasound is a useful, non-invasive, and feasible bedside imaging tool for the detection of inflammation, detection of complications, and follow-up of IBD patients when performed by the attending physician.

Validation of US evaluation of ulcerative colitis activity

This study was aimed at validating the inter-rater grading agreement for assessing disease activity in patients with established ulcerative colitis (UC) using transabdominal ultrasonography (US) versus colonoscopy (CS). Fifty-seven patients underwent US and CS at four facilities. UC disease activity was assessed using the original US grading system and CS Matts classification. Initially, the US and CS grades were assessed at each examining facility, and still images and movie clips were re-assessed at the central facility. Grading agreement between the examining and central facilities was evaluated. Grading agreement for US and CS were 0.75 and 0.72 in all segments and 0.82 and 0.70 in the maximum grade of each patient, respectively (all p < 0.001). US grading agreement was "almost perfect" for the maximum grade and "moderate" to "substantial" for other assessments. The inter-rater US grading agreement was good and not inferior to that of CS for evaluating UC disease activity.

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

Background/Aims

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

Methods

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

Results

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

Conclusions

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

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.

The use of ultrasound in inflammatory bowel disease

Imaging in inflammatory bowel disease (IBD) plays a pivotal role in the primary diagnosis, as well as during the management of patients with known IBD. The evolution of ultrasound equipment and the growing expertise of examiners have both enhanced the role of intestinal ultrasound in the assessment of the gastrointestinal tract in IBD patients. Intestinal ultrasound has been shown to have high sensitivity and specificity, as well as high positive and negative predictive value, in the detection or exclusion of intestinal inflammatory activity in IBD. The obvious advantages of intestinal ultrasound over other imaging modalities include non-invasiveness, rapid availability and low costs. This review summarizes the current developments in the use of intestinal ultrasound for the detection of IBD and its complications, and discusses its use in the management of patients with IBD. Indications for the use of intestinal ultrasound in daily practice are presented, expanded by new developments such as contrast-enhanced ultrasonography and elastography.