Introduction

In colorectal epithelial neoplasms, lesions classified as type 2B according to the Japan Narrow Band Imaging (NBI) Expert Team classification (JNET), which are characterized by irregular microsurface or microvascular patterns, are often difficult to diagnose accurately using NBI magnifying endoscopy (ME) alone. Therefore, supplementary pit pattern diagnosis using crystal violet (CV)-stained ME (CV-ME) is recommended. However, CV is potentially carcinogenic, and CV-ME is relatively complex and time-consuming. Acetic acid (AA)-enhanced NBI ME (ANBI-ME) has been proposed as a simpler and safer alternative. Based on our previous study identifying 4.5% AA as the optimal concentration[1], this study prospectively evaluated the diagnostic utility of 4.5% ANBI-ME as a substitute for CV-ME (UMIN registration number: 00045621).

Aims & Methods

From October 2021 to March 2024, colorectal lesions classified as JNET type 2B or 3 during colonoscopy were prospectively enrolled until 300 cases were included. Each lesion underwent ANBI-ME with 4.5% AA, followed by CV-ME. The area of suspected deepest invasion was selected, and one representative image from ANBI-ME and one from CV-ME were independently assessed by two expert endoscopists blinded to histopathology. Intermethod and interobserver agreement were evaluated using Cohen’s weighted kappa. Diagnostic accuracy for each modality was calculated using the individual and consensus diagnoses of the two experts (McNemar’s test). AA whitening duration (AD), representing a reversible mucosal reaction, was measured during ANBI-ME and analyzed by histological depth (low-grade dysplasia [LGD], high-grade dysplasia [HGD], superficial submucosal invasive carcinoma [SMs], and deep submucosal invasive carcinoma [SMd]) using Kaplan–Meier analysis and the log-rank test.

Results

After excluding four unresected lesions, 296 lesions were analyzed. Median lesion size was 18 mm. Locations included the cecum (30), ascending colon (47), transverse colon (69), descending colon (13), sigmoid colon (73), and rectum (64); 122 lesions were elevated and 174 flat. Histological diagnosis included 77 LGD, 145 HGD, 18 SMs, and 56 SMd. Good agreement was observed between modalities (κ = 0.65 and 0.62) and between observers (κ = 0.78 for ANBI-ME, κ = 0.66 for CV-ME). Consensus was reached in 216 ANBI-ME and 192 CV-ME cases. Diagnostic accuracy was significantly higher with ANBI-ME than CV-ME for both observers (81% vs. 76%, p = 0.028; 75% vs. 69%, p = 0.025). Among consensus cases, ANBI-ME also showed higher accuracy (66% vs. 57%, p < 0.01). Median AD (in seconds) was 52 for LGD, 80 for HGD, 132 for SMs, and 107 for SMd, with a significantly shorter duration observed in LGD (p < 0.001).

Conclusion

ANBI-ME demonstrated diagnostic performance equivalent to or superior to CV-ME for colorectal lesions classified as JNET type 2B or 3. In addition, AA whitening duration (AD) may complement the assessment of histological depth of invasion.

References

[1]. Shimizu T, Yamagata T, Kanno Y, et al. A single-center pilot study on the efficacy and safety of acetic acid-enhanced magnifying endoscopy with narrow-band imaging for diagnosis of colorectal epithelial neoplasms. Gastrointest Endosc. 2025;101(2):416-424.

Introduction

Capsule endoscopy (CE) is a minimally invasive and essential tool for assessing small bowel disorders, especially Crohn’s disease. Accurate detection of ulcers and erosions is vital for evaluating disease activity, guiding treatment, and monitoring therapeutic response. Although CE has revolutionized lesion detection, its manual interpretation remains time-consuming and subject to interobserver variability. Recent advances in artificial intelligence (AI), particularly convolutional neural networks (CNNs), offer promising solutions by enhancing diagnostic accuracy, reducing variability, and improving workflow efficiency. This study aimed to develop and validate a robust AI model capable of detecting and distinguishing small bowel ulcers and erosions across multiple CE platforms and clinical centers.

Aims & Methods

In a prospective, multicenter study conducted between January 2021 and April 2024, data were collected from centers in Portugal, Spain, and the United States. Two CE devices—PillCamSB3 and Olympus EC-10—were used to analyze 137 anonymized exams. The AI-assisted readings generated by a deep learning model were compared to standard-of-care (SoC) interpretations, with an expert consensus panel serving as the reference standard. Performance metrics included sensitivity, specificity, positive and negative predictive values (PPV, NPV), and area under the receiver operating characteristic curve (AUROC).

Results

Expert consensus identified ulcers and erosions in 56 patients (40.9%). Compared to the reference standard, SoC readings achieved 60.7% sensitivity, 98.8% specificity, 97.1% PPV, 78.4% NPV, and 83.2% accuracy. In contrast, the AI-assisted model achieved 94.6% sensitivity, 80.2% specificity, 76.8% PPV, 95.6% NPV, and 86.1% accuracy. The AI model was found to be both non-inferior (p < 0.001) and statistically superior (p < 0.001) to SoC. Notably, it identified 68 lesions, nearly double those detected by SoC (35), and demonstrated consistent performance across devices and centers. The mean AI-assisted reading time was 239 seconds (SD 138 seconds) per exam.

Conclusion

The AI-assisted model significantly outperformed conventional SoC in the detection of small bowel ulcers and erosions, achieving higher sensitivity and overall accuracy while substantially reducing reading time. This is the first multicenter validation of an interoperable AI solution for CE, capable of high diagnostic performance across different devices and clinical environments. These findings highlight the potential of AI to transform endoscopic evaluation and management in inflammatory bowel disease.

Introduction

Gastric mucosal visibility is essential for high-quality upper gastrointestinal (GI) endoscopy. While simethicone and N-acetylcysteine (NAC) have been shown to improve mucosal visibility, the optimal time interval between preparation and endoscopy remains undefined.

Aims & Methods

This randomized controlled trial evaluated the effect of timing on mucosal visibility and explored the upper limit beyond which visibility begins to decline.
In this single-center, randomized controlled trial, adult patients undergoing elective upper GI endoscopy were randomized into four groups: placebo, simethicone + NAC with endoscopy performed after 10–20 minutes, 20–30 minutes, and >30 minutes. The primary outcome was the proportion of patients achieving adequate gastric mucosal visibility (GMV), defined as a score of <7 on a validated visibility scale. A pre-specified subgroup analysis of the >30 minute group was performed by stratifying patients into 20-minute intervals (31–50, 51–70, and 71–90 minutes) to assess the durability of mucosal clarity over time.

Results

Comparison	Adequate gastric mucosal visibility (%)	P
10–20 min vs 20–30 min	27% vs 62%	0.001
10–20 min vs >30 min	27% vs 67%	0.001
10–20 min vs Placebo	27% vs 2.6%	0.001
20–30 min vs >30 min	62% vs 67%	0.174
20–30 min vs Placebo	62% vs 2.6%	0.001

1,140 patients (median age 42years, 63.2% males) were included in the study. Adequate GMV was significantly higher in all preparation groups compared to placebo (p < 0.001). The 20–30 minute and >30 minute groups demonstrated the highest rates of adequate visibility (61.5% and 73.5%, respectively), both significantly superior to the 10–20 minute group (26.9%) and placebo (2.6%). In the >30 minute subgroup analysis, the 31–50 minute interval demonstrated the highest adequacy (73.5%). The 51–70 minute group showed moderate adequacy (52.1%), which was not significantly different from the 20–30 minute group (p = 0.207). However, the 71–90 minute group had reduced adequacy (43.8%) and did not differ significantly from the 10–20 minute group (p = 0.145). No adverse events were reported across study arms.

Conclusion

Endoscopy performed between 20 and 50 minutes after mucosal preparation yields optimal gastric mucosal visibility. A decline in visibility beyond 50 minutes suggests a practical upper limit for endoscopy timing following preparation. These findings support structured, time-sensitive scheduling following mucosal cleansing to enhance procedural quality.

Disclosure

None