Abstract
The aim of this dissertation is to evaluate the benefit of Narrow Band Imaging (NBI), especially in the differentation of benign, precancerous and malignant changes in three groups of patients, it means in preoperative diagnostics in outpatient department (group I), during the endoscopic surgery (group II) and also in follow-up of patients after curative radiotherapy (group III). The vascular changes were classified according to Ni and Arens and subsequently correlated with the histopathological results.