Diagnostic Efficacy of Narrow Band Imaging (NBI) in Patients With Gastroesophageal Reflux Disease (GERD)

Gastroesophageal reflux disease (GERD) is a common disorder in Asia that includes erosive and non-erosive counterparts. The evaluation of intra-esophageal damage is of paramount importance because patients with erosive and those with non-erosive GERD have distinct manifestations and prognoses. Although proton-pump inhibitor (PPI) is the treatment of choice for erosive patients with excellent therapeutic response, the majority of reflux patients can be classified with non-erosive reflux disease (NERD).1 Not all of them demonstrate a favorable response to PPI treatment because the pathogenesis of NERD is in part associated with psychosomatic pathways.2 Their therapeutic response to PPI is unpredictable. Therefore, how to improve the diagnosis of reflux-induced mucosal damage under endoscopy is a worthwhile endeavor.

Minimal change esophagitis is commonly accepted as part of the spectrum of reflux esophagitis in Japan.3,4 This category is defined as "erythema without sharp demarcation, whitish turbidity, and/or invisibility of vessels due to these findings".3 Although the minimal change disease (MCD) can be recognized in a significant number of patients with reflux using endoscopy-first policy, the major drawback of this category from the Los Angeles system is due to a poor interobserver agreement (κ statistic = 0.2).

Narrow-band imaging (NBI) is a novel, noninvasive optical technique that adjusts reflected light to improve the contrast of capillary patterns compared with conventional illumination.5 This system is highly applicable in the detection of early-stage mucosal lesions, including oral cancer, Barrett's esophagus, gastric cancer, and colonic neoplasm.6-10 For the reflux patients we face on a daily basis, the NBI system has been proven to improve the intraobserver and interobserver reproducibilities in grading esophagitis with small erosive foci (improving overall κ value to 0.62 versus 0.45).11 Corresponding to the crowding of capillaries, inflamed mucosal breaks appear dark brown on NBI, which produces intense contrast against the normal squamous epithelium and the stomach mucosa. These properties may improve our ability to delineate the margins of small inflammatory foci. Based on this advantage, we plausibly hypothesize the use of this system may improve the description of MCD and enable the prediction of therapeutic response to PPI. Testing this hypothesis is the main goal of our study.

Aim of the Study To assess the clinical utility and therapeutic implications of NBI in evaluating reflux patients with minimal mucosal damage.