Infrared fluorescence endoscopy for the diagnosis of superficial gastric tumors

Background: Indocyanine green (ICG) is a fluorescent marker that is excited by rays at a wavelength of 768 nm to emit fluorescence at a wavelength of 807 nm in the infrared (IR) range. We developed an IR fluorescence endoscope (IRFE) to observe superficial gastric tumors and assessed its clinical usefulness. Objective: To evaluate the clinical usefulness of an IRFE for the assessment of superficial gastric tumors. Design: An observational study. Setting: University hospital. Interventions: Newly developed IRFE. Patients: Thirty patients with gastric tumors were enrolled in this study, and their lesions were subjected to endoscopic submucosal dissection (ESD), or laparoscopic gastrectomy after observation with the IRFE. Methods: Gastric lesions were subjected to conventional observation, followed by IR fluorescence observation before and after intravenous ICG (0.01 mg/kg) injection. Main Outcome Measurements: The relationship between the positive fluorescence and invasivity of each tumor. Results: Fluorescence was positive in 8 of 10 gastric cancers with submucosal invasion (80%) and I of 20 adenomas or intramucosal gastric cancers (5%); the difference was statistically significant (P < .01). Conclusion: IRFE is a useful diagnostic tool for estimating the invasivity of gastric tumors.