Linked color imaging(LCI),a new system for endoscopy modality,creates clear and bright endoscopic images by using short-wavelength narrow-band laser light combined with white laser light on the basis of magnifying blue laser imaging(BLI) technology.LCI makes red areas appear redder and white areas appear whiter.Thus,it is easier to recognize a slight difference in color of the mucosa.This is a study to assess the effectiveness of LCI for diagnosing esophageal minimal endoscopic lesions and Los Angeles classification system when compared to conventional white-light endoscopy (WLI).Gastroesophageal reflux disease(GERD) is a common disease that be defined as a condition which develops when the reflux of stomach contents cause troublesome symptoms and/or complications.Esophageal injury was classified according to the Los Angeles classification system,Non-erosive reflux disease(NERD) is defined by the presence of troublesome reflux-associated symptoms and the absence of mucosal breaks at endoscopy,which includes minimal change oesophagitis and no endoscopic abnormalities.LCI improved the visualization of the squamocolumnar junction (SCJ) by enhancing the contrast,mucosa minimal changes could be seen more easily and clearly with LCI than with standard white-light endoscopy.By comparing White-light endoscopy and LCI,it will show if there is any comparable advantage to using one or the other for lesion detection.

This is a prospective study comparing the use of linked color imaging(LCI) versus standard white light for the detection of minimal change esophageal.Gastroesophageal reflux disease(GERD) is a common disease that be defined as a condition which develops when the reflux of stomach contents cause troublesome symptoms and/or complications.At present,more than half the patients with GERD symptoms were diagnosed as having nonerosive reflux disease(NERD).However,by careful analysis,the majority of NERD patients did not have completely normal endoscopic finding but were found to have subtle distal esophageal mucosal changes.Forty-eight patients with suspected minimal change esophageal reflux disease(positive GerdQ but normal conventional endoscopy)and forty asymptomatic control were recruited.The new LCI(GF-L590WR) was performed.The criteria for positive liquid crystal thermography (LCT) were:a)triangular indentation,b)punctuate erythema.

Inclusion Criteria:

• age more than 18 year old
• ability to provide written informed consent and undergoing an upper endoscopy
• no PPI therapy in previous 2 weeks and no esophageal tumor or stenosis or history of esophageal surgery
• Patients with more than 3 reflux episodes/week and absence of mucosal breaks at conventional endoscopy，The PPI test was positive

Exclusion Criteria:

• unable to provide informed consent
• erosive esophagitis or diagnosis of erosive esophagitis within the recent 6 months
• presence of columnar lined epithelium
• evidence of cancer or mass lesion in the esophagus, gastric lesions (ulcer, polyp, cancer)
• previous gastrointestinal surgery
• esophageal strictures
• chronic use of medications known to affect esophageal motility
• presence of systemic diseases that might interfere with esophageal motility
• use of proton pump inhibitors(PPI) or histamine2-receptor antagonists in the last 4 weeks

Consecutive adult patients undergoing an outpatient endoscopy