Transcutaneous bowel sonography for inflammatory bowel disease is sensitive and specific when performed in a nonexpert low-volume North American center

Role of intestinal ultrasound in ulcerative colitis: A systematic review

BACKGROUND

Intestinal ultrasound (IUS) is an emerging, non-invasive, and highly sensitive diagnostic tool in inflammatory bowel disease (IBD), including ulcerative colitis (UC). Despite its potential, its adoption in clinical practice is limited due to a lack of standardization and awareness.

AIM

To perform a comprehensive scoping review based on a systematic literature review on IUS in UC to inform current practice.

METHODS

Ninety-nine original articles about ultrasonography in UC were identified among 7608 citations searching PubMed and EMBASE databases for systematic review.

RESULTS

IUS can be useful as an initial diagnostic strategy in patients with suspected IBD/UC. In UC, IUS can predict endoscopic response, histologic healing, and steroid responsiveness in acute severe cases. IUS can predict response to biologics/small molecules (as early as 2 wk). IUS correlates well with ileo-colonoscopy, but IUS could miss rectal, jejunal, and upper GI lesions in suspected IBD and colon polyps or extra-intestinal manifestations in known IBD. IUS is useful in special situations (children, pregnancy, and postoperative Crohn's disease). Inter-observer agreement is acceptable and trained physicians have comparable diagnostic accuracy. Point-of-care ultrasound impacted management in 40%-60% of cases. Hand-held IUS has excellent agreement with conventional IUS.

CONCLUSION

IUS is a non-invasive, highly sensitive tool in the diagnosis and monitoring of UC, offering excellent patient satisfaction. Point-of-care ultrasound by IBD physicians can significantly impact clinical decision-making.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

Systematic review: Defining, diagnosing and monitoring small bowel strictures in Crohn's disease on intestinal ultrasound

BACKGROUND

Stricturing Crohn's disease (CD) occurs most commonly in the terminal ileum and poses a clinical problem. Cross-sectional imaging modalities such as intestinal ultrasound (IUS), computed tomography enterography (CTE), and magnetic resonance enterography (MRE) allow for assessment of the entire bowel wall and associated peri-enteric findings. Radiologic definitions of strictures have been developed for CTE and MRE; their reliability and responsiveness are being evaluated in index development programs. A comprehensive assessment strategy for strictures using IUS is needed.

AIMS

To provide a detailed summary of definitions, diagnosis and monitoring of strictures on IUS as well as technical aspects of image acquisition.

METHODS

We searched four databases up to 6 January 2024. Two-stage screening was done in duplicate. We assessed risk of bias using QUADAS-2.

RESULTS

There were 56 studies eligible for inclusion. Definitions for strictures on IUS are heterogeneous, but the overall accuracy for diagnosis of strictures is high. The capability of IUS for characterising inflammation versus fibrosis in strictures is not accurate enough to be used in clinical practice or trials. We summarise definitions for improvement of strictures on IUS, and discuss parameters for image acquisition and standardisation.

CONCLUSIONS

This systematic review is the first step for a structured program to develop a stricture IUS index for CD.

Basic practices for gastrointestinal ultrasound

The standard diagnostic modalities for gastrointestinal (GI) diseases have long been endoscopy and barium enema. Recently, trans-sectional imaging modalities, such as computed tomography and magnetic resonance imaging, have become increasingly utilized in daily practice. In transabdominal ultrasonography (US), the bowel sometimes interferes with the observation of abdominal organs. Additionally, the thin intestinal walls and internal gas can make structures difficult to identify. However, under optimal US equipment settings, with identification of the sonoanatomy and knowledge of the US findings of GI diseases, US can be used effectively to diagnose GI disorders. Thus, the efficacy of GIUS has been gradually recognized, and GIUS guidelines have been published by the World Federation for Ultrasound in Medicine and Biology and the European Federation of Societies for Ultrasound in Medicine and Biology. Following a systematic scanning method according to the sonoanatomy and precisely estimating the layered wall structures by employing color Doppler make diagnosing disease and evaluating the degree of inflammation possible. This review describes current GIUS practices from an equipment perspective, a procedure for systematic scanning, typical findings of the normal GI tract, and 10 diagnostic items in an attempt to help medical practitioners effectively perform GIUS and promote the use of GIUS globally.

Usefulness of intestinal real-time virtual sonography in patients with inflammatory bowel disease

BACKGROUND AND AIM

Transabdominal ultrasonography (US) examination for the intestine is often difficult, and its precedence for intestinal examination depends on accessibility to experienced ultrasonographers. Real-time virtual sonography (RVS) assists examination of US as a fusion method by synchronizing US images with pre-captured computed tomography or magnetic resonance images. We aimed to evaluate the feasibility to use RVS for the examination of the intestine.

METHODS

The time to scan three parts of the intestine was compared between conventional US and RVS in seven participants without intestinal diseases. Whether RVS accurately synchronized US images with reference images of intestinal target lesions was judged in 20 patients with inflammatory bowel disease.

RESULTS

Examination time to scan the ascending colon and the ileocecum using intestinal RVS was significantly shorter than that using conventional US alone (36.7 vs 50.0 s [P = 0.0313] and 35.4 vs 66.4 s [P = 0.0156], respectively) in participants without intestinal diseases. Well-synchronized US images of the intestinal lesions, such as stenosis, with reference computed tomography/magnetic resonance images were obtained by RVS in all the lesions in the fixed parts of the colon (ascending and descending colon), and images of nine lesions in 12 lesions (75%) were well synchronized in the unfixed part of the intestine in Crohn's disease patients.

CONCLUSION

Real-time virtual sonography significantly reduced the examination time of intestinal US. Intestinal RVS can help the ultrasonographer to guide the US probe to detect and monitor intestinal lesions by synchronizing reference images, especially in inflammatory bowel disease patients (UMIN Clinical Trials Registry number: UMIN000011571).

Noninvasive testing in the management of children with suspected inflammatory bowel disease

Objective: To assess the accuracy of noninvasive parameters, fecal calprotectin (FC), increased bowel wall thickening (BWT) at intestinal ultrasound (IUS) and blood inflammatory indexes (BII), alone or in combination, as diagnostic tools for inflammatory bowel disease (IBD) in pediatric patients. Methods: Retrospective data were collected on consecutive children (age 2-18 years) referred to our pediatric gastroenterology clinic, for recurrent abdominal pain and/or altered bowel habit from 2007 to 2013. Subjects who had diagnostic workup: laboratory tests (FC, BII, white blood cell (WBC), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)) and IUS as initial assessment were eligible. Subjects with known gastrointestinal (GI) diseases, or signs or symptoms highly suggestive for organic diseases necessitating prompt endoscopy (e.g., perianal disease or rectal bleeding), or who had recently performed endoscopy were excluded. The accuracy of noninvasive tests for detecting IBD was assessed using endoscopic and/or radiological investigations, performed in subsequent clinical follow up, as reference gold standard. Results: Seventy-seven patients (mean age 11.3, 44 males) were included, 23 (29.9%) with a final diagnosis of IBD. As single tests, FC gave the highest sensitivity (96%) but lower specificity (72%) and IUS highest specificity (96%) with lower sensitivity (70%). The combination of FC + IUS showed excellent accuracy for detecting children with IBD with positive predictive value: 100%; negative predictive value: 88.5%. The probability of IBD in children with normal FC, BII and IUS was 0.09%. Conclusions: FC and increased BWT at IUS are accurate to guide reassurance or proceeding with further invasive procedures for detecting IBD in children with mild GI symptoms.

Can ultrasound be used as the primary imaging in children with suspected Crohn disease?

BACKGROUND

There is growing literature on the use of ultrasound (US) for evaluation of Crohn disease in adults, but few studies have been conducted on children. Several studies demonstrated high accuracy of US in the diagnosis of Crohn disease. Using US as the primary screening imaging modality for Crohn disease can reduce health care costs, the need for sedation and ionizing radiation exposure.

OBJECTIVE

The aim of our study is to determine if US can be used for screening evaluation of pediatric Crohn disease.

MATERIALS AND METHODS

A prospective cohort study of pediatric patients undergoing MR enterography (MRE) for suspected or known history of Crohn disease was performed, with gray-scale and Doppler US of the terminal ileum done immediately before or after MRE. US images were interpreted by two radiologists (Reader 1 and Reader 2) not involved in image acquisition, in blinded and randomized fashion. US findings of Crohn disease including bowel wall thickening, wall stratification, increased vascularity on Doppler, lymphadenopathy, fat infiltration and extraintestinal complications were evaluated. MRE findings of terminal ileitis were considered the reference standard. Demographic data, body mass index (BMI), symptoms, and laboratory, endoscopic and histopathological data were obtained from electronic medical records.

RESULTS

Forty-one patients (mean age: 13.7 years: 4.6-18.9 years) were evaluated. Mean BMI was 21.2 (range: 13-40.2); 10 patients (24.3%) were either overweight or obese. Final diagnoses were Crohn disease (n=24), ulcerative colitis (n=4) and normal/non-inflammatory bowel disease-related diagnoses (n=13). US demonstrated sensitivity of 67% and 78% and specificity of 78% and 83%, by Reader 1 and Reader 2, respectively. MRE sensitivity and specificity were 75% and 100%, respectively, compared to final clinicopathological diagnosis. Interobserver agreement between Reader 1 and Reader 2 was good (0.6< kappa <0.8).

CONCLUSION

In screening for Crohn disease in children, US has limited sensitivity for detecting terminal ileitis.

Bowel Thickening in Crohn's Disease: Fibrosis or Inflammation? Diagnostic Ultrasound Imaging Tools

The high frequency of intestinal strictures in patients with Crohn's disease and the different treatment approaches specific for each type of stenosis make the differentiation between fibrotic and inflammatory strictures crucial in management of the disease. However, there is no standardized approach to evaluate and discriminate intestinal strictures, and until now, there was no established cross-sectional imaging modality to detect fibrosis. New techniques, such as contrast-enhanced ultrasound and sonoelastography allow the assessment of vascularization and mechanical properties of stenotic bowel tissue, respectively. These techniques have shown great potential to characterize strictures in Crohn's disease. The aim of this review is to sum up the current knowledge on bowel ultrasound tools to discriminate inflammatory from fibrotic stenosis in Crohn's disease considering the most recent published studies in the field.

Effect of tight junction protein of intestinal epithelium and permeability of colonic mucosa in pathogenesis of injured colonic barrier during chronic recovery stage of rats with inflammatory bowel disease

OBJECTIVE

To discuss the changes in the tight junction protein of intestinal epithelium and permeability of colonic mucosa and its possible mechanism by building the rat mode of inflammatory bowel disease at the chronic recovery stage.

METHODS

A total of 36 SD rats were divided into the model group and control one according to the random number table, with 18 rats in each group. Rats in the model group were given the 3% dextran sulfate sodium solution by the way of drinking for 7 d to build the rat model of inflammatory bowel disease, while rats in the control group were given free drinking of water. Six rats were executed at day 7, 14 and 21 respectively. The colonic tissues were collected from rats to observe the pathological changes of colonic mucosa. The activity of myeloperoxidase was detected and the white blood count was performed for rats in each group. The Ussing chamber technique was employed to detect the transepithelial electrical resistance (TER) and short-circuit current (SC) of colonic mucosa of rats in different time intervals; the quantum dots labeling technique was employed to detect the expression level of claudin-1 and claudin-2 in the colonic tissues.

RESULTS

After the successful modeling, the weight of rats in the model group was significantly reduced, while the disease activity index score was increased. The weight was at the lowest level at day 14 and then it began to increase afterwards. The disease activity index score was at the highest level at day 12 and then it began to decrease gradually. The activity of myeloperoxidase and WBC for rats in the model group all reached the peak value at day 14 and then decreased gradually. There was no significant difference in the changes of TER and SC in different time intervals for rats in the control group (P > 0.05). TER of model group was at the lowest level at day 14 and then increased gradually; SC was at the highest level at day 14 and then decreased gradually. TER of model group at day 7, 14 and 21 was significantly lower than that of control group, while SC of model group was significantly higher than that of control group (P < 0.05). There was no significant difference in the change of mean fluorescence intensity of claudin-1 and claudin-2 in different time intervals for rats in the control group (P > 0.05). The claudin-1 and claudin-2 for rats in the model group reached the highest level at day 14 and then decreased gradually. The claudin-1 and claudin-2 of model group at day 7, 14 and 21 was significantly higher than that of control group (P < 0.05).

CONCLUSIONS

After the acute stage, the inflammatory bowel disease is then in the chronic recovery stage; the increased permeability of colonic mucosa and increased expression of tight junction protein of intestinal epithelium are closely related to the pathogenesis and development of disease. The tight junction protein plays a key role in the pathogenesis of injured colonic barrier of inflammatory bowel disease.

Ultrasonographic evaluation of gastrointestinal graft-versus-host disease after hematopoietic stem cell transplantation

Gastrointestinal graft‐versus‐host disease (GI‐GVHD) is a major and life‐threatening complication of hematopoietic stem cell transplantation (HSCT). This study evaluated the efficacy of ultrasonography (US) for assessing and monitoring GI‐GVHD. GI tract was evaluated by US in 81 patients. US findings were positive in 43 patients, including 11 false positive, and negative in 38 patients. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of US for the diagnosis of GI‐GVHD were 100%, 78%, 74%, 100%, and 86%, respectively. Diffuse wall thickening of the ileum was the most frequent finding in patients with GI‐GVHD. Severity of GI‐GVHD was correlated with the thickness of internal low echoic layer of the wall, the echogenicity of mesenteric fat tissue, and the intensity of Doppler signaling. We classified US findings of GI‐GVHD into four US grades. There was a significant correlation between clinical stage of GI‐GVHD and the US grade. These ultrasonographic abnormalities were improved with clinical improvement of GI‐GVHD upon treatment. Thus, US is an effective and efficient non‐invasive means of identifying the extent and severity of GI‐GVHD and monitoring response to treatment.

Imaging the small bowel

PURPOSE OF REVIEW

Radiologic investigations continue to play a pivotal role in the diagnosis of pathologic conditions of the small intestine despite enhancement of capsule endoscopy and double-balloon endoscopy. Imaging techniques continue to evolve and new techniques in MRI in particular, are being developed.

RECENT FINDINGS

Continued advances in computed tomography (CT) and MRI techniques have reinforced the importance of these imaging modalities in small bowel assessment. The more invasive enteroclysis technique yields better small bowel distension for both CT and MRI when compared with peroral enterography, but no clinically significant difference is seen in terms of diagnostic accuracy. Recent concern regarding radiation exposure means that MRI is gaining in popularity. Fluoroscopic studies such as barium follow through and small bowel enteroclysis are being replaced by the cross-sectional alternatives. Contrast-enhanced ultrasound is showing results comparable with CT and MRI, but concern remains regarding reproducibility, especially outside centres that specialize in advanced sonographic techniques.

SUMMARY

CT and MRI enterography are comparable first-line modalities for patients with suspected small bowel disease, but magnetic resonance enterography is favoured given the absence of ionizing radiation. Capsule endoscopy is a reasonable alternative investigation in exploration of chronic gastrointestinal blood loss, but is best kept as a second-line test in patients with other symptoms.