Abstract
The Los Angeles Classification System (LA system) is widely used as endoscopic criteria for identifying reflux esophagitis and focuses on describing the extent of visible mucosal breaks. In Japan, the LA system has been modified (modified LA system) to include grade N, defined as no endoscopic findings, and grade M, defined as minimal changes in the mucosa such as erythema and/or whitish turbidity. To establish accurate diagnosis of esophagitis by endoscopy, some key points and techniques must be noted. First, the endoscopist should require patients to take a deep breath dilating the lower esophagus so the endoscopist can easily detect the squamo-columnar junction (SCJ) circumferentially. Second, we need to observe the mucosa of the SCJ both carefully and precisely to detect the presence of mucosal breaks or minimal changes. Close-up observation and/or image-enhanced endoscopy can distinguish erosion from erythema and white plaque from squamous epithelium in terms of partial mucosal injury. In particular, it is important to establish endoscopic diagnostic criteria and a training program for endoscopic diagnosis of minimal changes.
