Narrow-band imaging for scar (NBI-SCAR) classification: from conception to multicenter validation

Area of Science:

• Gastroenterology
• Endoscopic Imaging
• Pathology

Background:

• Current surveillance of post-endoscopic resection (ER) scars often involves biopsies, but standardized criteria are lacking.
• Clinical practice for scar surveillance after ER is variable.
• There is a need for a reliable classification system for post-ER scars.

Purpose of the Study:

• To develop and validate a novel classification system for post-ER scars using advanced imaging criteria.
• To establish standardized criteria for evaluating scars after endoscopic resection.
• To improve the accuracy of scar assessment and reduce unnecessary biopsies.

Main Methods:

• Developed the Narrow-Band Imaging for Scar (NBI-SCAR) classification based on specific endoscopic features.
• Assessed scars using high-definition white-light endoscopy (HD-WLE) and narrow-band imaging (NBI).
• Correlated endoscopic predictions with histopathology and validated findings across multiple international endoscopy settings.

Main Results:

• NBI-SCAR demonstrated significantly higher sensitivity (100%) compared to HD-WLE (73.7%) in the exploratory phase.
• In the validation phase, NBI-SCAR achieved 96.4% sensitivity among experienced endoscopists.
• Substantial inter-rater (κ = 0.61) and moderate intrarater (S = 0.52) reliability were observed.

Conclusions:

• NBI-SCAR offers high sensitivity and negative predictive value for excluding recurrence in post-ER scars.
• This classification system aids experienced endoscopists in accurately evaluating scars.
• NBI-SCAR may help mitigate the burden of unnecessary biopsy samples during surveillance.