Objective quantification of the vocal fold vascular pattern: comparison of narrow band imaging and white light endoscopy

No clinical standard procedure has yet been defined to quantify the vascular pattern of vocal folds. Subjective classification trials have shown a lot of promise. Narrow band imaging (NBI) as an endoscopic imaging tool is useful, because it shows the vascular structure clearer than white light endoscopy (WL) alone. Endoscopic images of 74 human vocal folds (NBI and WL) were semi-automatically evaluated after image processing with respect to pixels of vessels and mucosa by the software MeVisLab. The ratios of vessel/mucosa pixels were compared. Using NBI, more vocal fold vessels are visible compared with WL alone (p = 0.000). There may be a difference between the right and left vocal folds due to the handedness of the examiner (p = 0.033) without any interaction between the method (NBI/WL) and the side (right/left) (p = 0.467). MeVisLab is a suitable tool for the objective quantification of the vessel/mucosa ratio for NBI and WL endoscopic images. NBI is an appropriate endoscopic tool for examination of diseases of vocal folds with changes in the vascular pattern. There is evidence that the handedness of the examiner may have an influence on the quality of the examination between the right and left vocal folds.