Experiences with 'optical' biopsies of leukoplakia of the vocal folds

Background: it is often difficult to distinguish leucoplakia from carcinoma or chronic laryngitis. In this study, we examined if color texture optical biopsies are able to detect leukoplakia reliably and to distinguish this from normal vocal fold tissue. Methods: 25 images from patients with a normal larynx and 25 images from patients with leucoplakia were analysed retrospectively. The images were recorded with a rigid 90degrees-laryngoscope (Wolf((R)) Typ 4450.571) during a clinical setting and were recorded by a S-VHS-videorecorder. With a software program (InSegT((R))), regions with leucoplakia, normal tissue and suspicious tissue were manually marked. Within each marked region, the use of color texture analysis numeric features were calculated to characterize the surface in texture and color. Color histogramms (HST), Sum- and Difference histogramms (S/D), Statistical Geometric Features (SGF) and Grey-Value-Dependent-Matrix (GLDM) were used. Patients: 29 women and 21 men (age 18 to 81 years, average of 53 years), who were examined in our clinic from 10/1999 - 8/2003, took part in this study. Results: The automatized classification for color texture analysis resulted in 71% for leucoplakia and 97% for normal tissue. Conclusion: Optical biopsies can contribute to find the correct diagnosis. However, classification results must still get better when optical biopsies should be used in clinical practice.