Catheter probe assisted endoluminal US in inflammatory bowel disease

Role of through-the-scope catheter-based EUS in inflammatory bowel disease diagnosis and activity assessment

BACKGROUND AND AIMS

Distinguishing Crohn's disease (CD) from ulcerative colitis (UC) may be difficult when the disease is limited to the colon. Transmural healing is an important adjunctive measure of inflammatory bowel disease activity. The aim of this study was to examine the role of EUS in differentiating CD versus UC and evaluating transmural disease activity.

METHODS

This prospective cohort study enrolled 20 patients with CD (10 active [aCD], 10 inactive), 20 patients with UC (10 active [aUC], 10 inactive), and 20 control subjects who underwent colonoscopy from 2019 to 2021 at a tertiary care center. Measurements of bowel wall layer thickness from the rectum and cecum were obtained using a through-the-scope US catheter (UM-3R-3; Olympus, Center Valley, Penn, USA) at the time of colonoscopy.

RESULTS

Compared with control subjects, patients with aCD had thicker rectal submucosa and total wall layer (submucosa median, 1.80 mm [interquartile range {IQR}, 1.40-2.00] vs .60 mm [IQR, .40-.70]; total wall median, 3.70 mm [IQR, 3.52-4.62] vs 2.10 mm [IQR, 1.70-2.40], respectively; P < .01). Similar significant findings were observed for the cecal wall layers. Compared with control subjects, patients with aUC had thicker rectal mucosa and total wall but not submucosa or muscularis propria layers (mucosa median, 1.35 mm [IQR, 1.12-1.47] vs .60 mm [IQR, .57-.70]; total wall median, 3.45 mm [IQR, 2.85-3.75] vs 2.10 mm [IQR, 1.70-2.40], respectively; P < .01). Patients with aCD compared with those with aUC had a significantly thicker rectal submucosa layer (median, 1.80 mm [IQR, 1.40-2.00] vs .55 mm [IQR, .40-.75], respectively, P < .01). Cutoff values of 1.1 mm for rectal submucosa in CD (sensitivity, 1.0; specificity, 1.0) and 1.1 mm for rectal mucosa in UC (sensitivity, .8; specificity, .9) were found to differentiate active from inactive disease.

CONCLUSIONS

EUS measurements of colon wall layers can help diagnose aCD versus aUC and assess transmural disease activity. (Clinical trial registration number: NCT03863886.).

The Use of Endoscopic Ultrasonography in Inflammatory Bowel Disease: A Review of the Literature

The diagnosis of inflammatory bowel disease (IBD) can sometimes be challenging. By corroborating clinical, imaging and histological data, the two main entities of IBD, ulcerative colitis and Crohn's disease (CD), can be differentiated in most cases. However, there remains 10-20% of patients where the diagnosis cannot be accurately established, in which case the term "IBD unclassified" is used. The imaging techniques most used to evaluate patients with IBD include colonoscopy, ultrasonography and magnetic resonance imaging. Endoscopic ultrasonography is mainly recommended for the evaluation of perianal CD. Through this work, we aim to identify other uses of this method in the case of patients with IBD.

Reliability of EUS indices to detect inflammation in ulcerative colitis

BACKGROUND AND AIMS

EUS is a potentially useful modality to assess severity of inflammation in ulcerative colitis (UC). We assessed the reliability of existing EUS indices and correlated them with endoscopic and histologic scores.

METHODS

Four blinded endosonographers assessed 58 endoscopic and EUS videos in triplicate, from patients with UC. Intrarater and interrater reliability of the hyperemia and Tsuga scores were estimated by using intra-class correlation coefficients (ICCs). Correlation with the Mayo endoscopy score, modified Baron score (MBS), Ulcerative Colitis Endoscopic Index of Severity (UCEIS), and Geboes histopathology score (GHS) were calculated by using bootstrapping methods. A RAND consensus process led to development of standardized definitions and a revised EUS-UC score.

RESULTS

ICCs for intrarater reliability were 0.76 (95% confidence interval [CI], 0.71-0.80) for the hyperemia score and 0.85 (95% CI, 0.79-0.89) for the Tsuga score. Corresponding values for interrater reliability were 0.34 (95% CI, 0.25-0.42) and 0.36 (95% CI, 0.24-0.46). Correlation between hyperemia and Tsuga scores to Mayo scoring system, MBS, UCEIS, and the GHS were 0.39 (95% CI, 0.15-0.61) and 0.28 (95% CI, 0.04-0.51), 0.38 (95% CI, 0.16-0.57) and 0.25 (95% CI, -0.01-0.48), 0.41 (95% CI, 0.16-0.62) and 0.27 (95% CI, 0.01-0.50), 0.37 (95% CI, -0.01-0.48) and 0.24 (95% CI, 0.13-0.57), respectively. The revised EUS-UC score included bowel wall thickening, depth of inflammation, and hyperemia.

CONCLUSIONS

Although substantial to almost perfect intrarater agreement existed for EUS indices in UC, interrater agreement was fair. Standardization of item definitions with development of a revised evaluative instrument has potential application as an evaluative and prognostic tool for UC. (Clinical trial registration number: NCT01852760.).

Endoscopic ultrasound of the colon for the differentiation of Crohn's disease and ulcerative colitis in comparison with healthy controls

BACKGROUND

Diagnosis of inflammatory bowel disease (IBD) is based on clinical presentation, colonoscopy and histology. Differentiation of Crohn's disease (CD) and ulcerative colitis (UC) can be difficult in some patients. Endoscopic ultrasound (EUS) provides high resolution images of the gastrointestinal wall (GI) and may be an alternative to differentiate CD/UC.

AIM

EUS of the GI layers in patients with IBD and healthy controls (HC) for the differential diagnosis of UC/CD in a prospective, blinded study.

METHODS

Consecutive patients with CD, UC or HC underwent EUS in the mid sigmoid colon with a forward-viewing radial echoendoscope. Mucosal, submucosal, total wall thickness (TWT) and locoregional lymphnodes (LN) were assessed by EUS in a blinded fashion. TWT was correlated with macroscopic IBD scores and histological inflammation scores.

RESULTS

Total wall thickness of 61 HC was 1.71 ± 0.02 mm, and 3.51 ± 0.15 mm in n = 52 with active IBD. In patients with active UC significant thickening of the mucosa was observed but nearly normal submucosa and m.propria. In active CD significant thickening of the submucosal layer was seen with nearly normal mucosa and m.propria [MucosaUC  = 2.08 ± 0.11 mm, MucosaCD  = 1.32 ± 0.17 mm (P = 0.0001); SubmucosaUC  = 1.01 ± 0.08 mm, SubmucosaCD  = 2.01 ± 0.22 mm (P = 0.0001)]. In 73.7% of patients with active CD, but in none with UC, paracolonic lymph nodes were detected. When mucosal-submucosal and TWT and LNs were combined, the sensitivity was 92.3% for the differentiation of active UC/CD. There was a strong correlation of TWT with histological inflammation scores (UC: r = 0.43; CD: r = 0.69).

CONCLUSIONS

Increased total wall thickness has a high positive predictive value for active IBD. EUS can differentiate active UC from CD and quantify the level of colonic inflammation.

Role of endoscopic ultrasonography in predicting the response to cyclosporin A in ulcerative colitis refractory to steroids

BACKGROUND AND AIMS

Although cyclosporin A has been reported to be effective in the treatment of severe ulcerative colitis, factors predicting its therapeutic efficacy remain unclear. Technical progress in endoscopic ultrasonography has improved visualisation of the structure of the colon wall. Here, to assess the value of endoscopic ultrasonography in predicting the response to cyclosporin A treatment, we evaluated the therapeutic effect of cyclosporin A by determining the pre- and post-cyclosporin A thickness of the mucosal layer in the rectum using endoscopic ultrasonography with an ultrasonic catheter probe.

PATIENTS AND METHODS

Fifteen ulcerative colitis patients who did not respond to high-doses of corticosteroids were treated with cyclosporin A by continuous intravenous infusion at 4mg/kg/day for 20 days. Before and 20 days after cyclosporin A therapy, clinical disease activity was assessed using clinical activity index scores. Colonoscopy and endoscopic ultrasonography were undertaken before and 20 days after cyclosporin A therapy.

RESULTS

Following treatment with cyclosporin A, nine patients showed a decrease in clinical activity index score by six points or more and were defined as responders, while the other six were defined as non-responders. Endoscopic ultrasonography measurement using an ultrasonic catheter probe showed that thickness of the rectal mucosal layer before cyclosporin A was significantly greater in responders than in non-responders (p<0.05). Further, thickness after cyclosporin A was statistically decreased (p<0.01) in the responders but not in the non-responders.

CONCLUSIONS

The ultrasonic catheter probe may represent a useful means of predicting and evaluating the efficacy of cyclosporin A treatment in severely ill ulcerative colitis patients.

Clinical usefulness of EUS for active ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with repeated flare-ups. It is difficult to predict the response to medical treatment and the necessity for surgery.

OBJECTIVE

We undertook this study to determine whether EUS is useful for evaluating the depth of intestinal inflammation, predicting the response to medical treatment, and determining the necessity for surgery in active UC.

DESIGN

Both the in vivo and in vitro studies used an observational design.

METHODS

In vitro, the depth of intestinal inflammation on EUS was compared with histopathologic findings in 13 cases of surgically resected UC. In vivo, the severest lesions on colonoscopic examination were evaluated by EUS in 42 patients with active UC to identify US characteristics that indicated the need for surgery.

RESULTS

In vitro, the degree of vertical spread of intestinal inflammation of UC on EUS was consistent with histopathologic findings in 45 of 50 sites (90%) studied. In vivo, intestinal inflammation was evaluated to discover whether it extended into the muscularis propria or deeper on preoperative EUS in a significantly higher percentage of patients who required surgery (67%, 10/15) than in patients in whom remission was induced by medical treatment (19%, 5/27; P = .002).

CONCLUSIONS

EUS can accurately and objectively evaluate the degree of vertical spread of intestinal inflammation in UC. EUS is useful for predicting the response to medical treatment and for determining the necessity for surgery in active UC.

Prospective evaluation of high-frequency mini-probe ultrasound colonoscopic imaging in ulcerative colitis: a valid tool for predicting clinical severity

BACKGROUND

High-frequency mini-probe ultrasound imaging permits trans-mural cross-sectional imaging of the colorectal wall. In ulcerative colitis, prognosis is dependent on the severity of mucosal inflammatory change where accurate assessment of disease activity is required to optimize medical therapy. Furthermore, predicting relapse of disease using conventional endoscopic, histopathological and clinical criteria has not proven reliable.

AIM

To evaluate the correlation of high-frequency mini-probe imaging with standardized measures of clinical, endoscopic and histopathological severity.

METHODS

High-frequency ultrasound images were obtained from the caecum to rectum in 200 patients. Tsuga colorectal ultrasound criteria were then compared to the endoscopic Baron score, Seo activity score and Matts histopathological grade.

RESULTS

For rectal disease, the kappa coefficient between Tsuga criteria I/II and Matts grade 1/2 was 0.78 (95% CI, 0.67-0.89), 0.57 (95% CI, 0.46-0.68) and 0.48 (95% CI, 0.34-0.62) for Tsuga class IIIa/b, IVa/b and Matts grade 3a/b and 4, respectively. Colonic imaging showed a kappa coefficient between Tsuga class I/II and Matts grade1/2 of 0.76 (95% CI, 0.72-0.8). Tsuga class IIIa-IIIb/IVa-IVb as compared to Matts grade 3a-3b/4 yielded kappa coefficients of 0.49 (95% CI, 0.43-0.55) and 0.62 (95% CI, 0.56-0.69), respectively. In the rectum both the total wall thickness, mucosa and submucosa were significantly thicker in Matts grade 3b and 4 disease as compared to Matts grade 1/2 (P < 0.02) for all parameters. A significant increase in colonic total wall thickness was observed between Matts score 4 and Tsuga grade 1-3a disease (P < 0.001).

CONCLUSIONS

High-frequency ultrasound is a valid adjunctive 'tool' for the trans-mural assessment of the colorectal wall in ulcerative colitis. This technique may aid in the initial diagnosis, and ongoing chronic management of disease.

Optical coherence tomography in the gastrointestinal tract

Conventional gastrointestinal endoscopic instruments have provided ready access to the mucosal surface of the esophagus, stomach,small intestinal, colon, bile duct, and pancreatic duct. The evolution of endoscopic ultrasonography has provided an additional dimension to the clinical application of modern endoscopy and imaging technology.

Gastrointestinal endoscopic ultrasonography

Although conventional endoscopy provides excellent visualization of gastrointestinal mucosa, it provides little information about intramural or nearby extramural lesions. The imaging of intraabdominal structures by conventional transabdominal ultrasound is degraded by ultrasound energy attenuation with distance. The provision of an ultrasound probe on a flexible gastrointestinal endoscope, to form an echoendoscope, provides excellent imaging of the gastrointestinal wall and of adjacent extramural structures. During the last two decades, endoscopic ultrasound, using an echoendoscope, has revolutionized the diagnosis and treatment of gastrointestinal diseases that affect the submucosa, deep bowel wall, and adjacent extramural structures. This article reviews the role of endoscopic ultrasound in the diagnosis and treatment of gastrointestinal disease, including standard and promising new applications, as well as standard and emerging new technology.

The role of endoscopic ultrasound in inflammatory bowel disease

Ultrasonography has been applied to the diagnosis and management of inflammatory bowel disease for over 20 years. The combination of endoscopy with ultrasound has resulted in the application of intraluminal sonographic imaging to multiple diseases, including inflammatory bowel disease. Initial efforts were focused on the sonographic assessment of disease severity as based on bowel wall thickness, but this has been inconsistently demonstrated. Furthermore, disease severity is a clinical assessment that is based on both clinical and imaging studies. Recognizing that Crohn's disease tends to be transmural and ulcerative colitis a superficial mucosal inflammatory process, hopes were raised that endosonography would be effective in discriminating cases of otherwise indeterminate colitis. Efforts to demonstrate this, however, have been largely disappointing, and EUS plays a limited role in discriminating ulcerative colitis from Crohn's disease. On a more positive note, EUS evaluation of perirectal and perianal complications of Crohn's disease has been demonstrated to be superior to fistulography, CT, and equal to or superior to MRI. Because accurate anatomic information is required to guide surgical therapy of these lesions, EUS has the potential to emerge as a powerful imaging tool in the management of perianorectal Crohn's disease.