The Efficacy of i-Scan for Detecting Reflux Esophagitis
Condition: Gastroesophageal Reflux Disease; Reflux Esophagitis
MeSH terms: Gastroesophageal Reflux; Esophagitis, Peptic; Esophagitis
Study type: Interventional

Summary: 
      Endoscopy is a widely used modality for the diagnosis and classification of Gastroesophageal
      reflux disease (GERD), and the extent of esophageal mucosal breaks on endoscopy can be
      assessed. However, there were some limitation in diagnosis of GERD using endoscopy

        1. More than half of patients with GERD reveal no visible abnormality on conventional
           endoscopy, it is possible that minute mucosal changes are underestimated by conventional
           endoscopy due to the limitation of visual ability

        2. In addition of uncertainty in detecting mucosal breaks, uncertainty in describing
           severity of mucosal injury can lead to inconsistency among interpreters. Interobserver
           agreement regarding diagnosis and classification of GERD using endoscopy is
           unsatisfactory to apply daily practice.

      Thus, the development of a new method to define the intra-esophageal injury for use in daily
      practice is a worthwhile endeavor and developed, such as narrow-band imaging (NBI), Fuji
      Intelligent Chromoen-doscopy (FICE) and i-scan.

      Among them, i-scan technology is the most recently developed image enhancing technology,
      which consists of three modes of image enhancement, i.e. surface enhancement (SE), contrast
      enhancement (CE), and tone enhancement (TE).

      Thus, the investigators examined the hypothesis that i-scan can improve the detection rate of
      reflux esophagitis and inter-observer agreement between endoscopists compared with
      conventional white light (WL) endoscopic examination.
    

Detailed description: 
      Gastroesophageal reflux disease (GERD) is a condition that develops when reflux of stomach
      contents causes troublesome symptoms and/or complications. It is the most frequent problem in
      upper gastrointestinal tract in outpatient clinic and contributes substantially to morbidity
      and to costs. Endoscopy is a widely used modality for the diagnosis and classification of
      GERD, and the extent of esophageal mucosal breaks on endoscopy can be assessed. However,
      because more than half of patients with GERD reveal no visible abnormality on conventional
      endoscopy, it is possible that minute mucosal changes are underestimated by conventional
      endoscopy due to the limitation of visual ability.

      In addition of uncertainty in detecting mucosal breaks, uncertainty in describing severity of
      mucosal injury can lead to inconsistency among interpreters. Asian gastroenterologists tend
      to diagnose endoscopically before they treat patients with symptoms suggestive of GERD and
      use the modified Los Angeles (LA) classification system that includes minimal changes as
      constituting a distinct grade of reflux esophagitis. In modified LA system, minimal change
      esophagitis is characterized by the mucosa such as erythema and/or whitish turbidity.
      However, because substantial overlap is noted between normal and minimal change, minimal
      change and LA class A, and LA class A and B, interobserver agreement regarding diagnosis and
      classification of reflux esophagitis is unsatisfactory to apply daily practice. Thus, the
      development of a new method to define the intra-esophageal injury for use in daily practice
      is a worthwhile endeavor.

      Currently, new imaging technologies have applied in endoscopy to improve detecting and
      differentiating the subtle mucosal changes using digital contrast method such as narrow-band
      imaging (NBI), Fuji Intelligent Chromoen-doscopy (FICE) and i-scan. Among them, i-scan
      technology is the most recently developed image enhancing technology, which consists of three
      modes of image enhancement, i.e. surface enhancement (SE), contrast enhancement (CE), and
      tone enhancement (TE). SE enhances light-dark contrast and CE adds blue color in relatively
      dark areas digitally, by obtaining luminance intensity data for each pixel. Applying SE and
      CE might allow detailed observation of subtle irregularities around the surface and TE
      analyzes the individual RGB components of a normal image and recombines the color frequencies
      of each component to enhance minute mucosal structures with subtle color changes.

      Thus, the investigators examined the hypothesis that i-scan can improve the detection rate of
      reflux esophagitis and inter-observer agreement between endoscopists compared with
      conventional white light (WL) endoscopic examination
    

Intervention name(s): i-scan
Intervention type(s): Device
Intervention description(s): For all the study procedures, Pentax EPKi processor and high-resolution adult video endoscopes (EG-2890i; Pentax, Japan) with push button switch from WL to i-scan were used. I-scan consist of three modes of image enhancement including SE, CE, ant TE. For SE and CE, switching among three enhancement levels (2+,3+,4+) is possible. Although SE and CE modes can allow detailed observation of subtle mucosal irregularities, noise increases as enhancement becomes more intense. In addition, TE is possible to switch p (pit pattern), v (vessel), b (Barrett), e (esophagus), g (stomach) and c (colo-rectum) mode.
Other intervention name(s): Pentax EPKi processor and EG-2890i endoscopy
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Diagnostic
Keywords: Gastroesophageal Reflux Disease; Reflux esophagitis; i-scan