Autofluorescence imaging in the diagnosis of laryngeal cancer

Differences in autofluorescence (fluorescence without photodynamic drugs) between normal and malignant tissues offer new possibilities in detecting and localizing early laryngeal carcinoma. Autofluorescence imaging was performed using a modified fluorescence endoscopy system from Xillix Technologies (Richmond, Canada). Fluorescence was induced by blue light at 442 nm and captured by an image-intensified camera through a laryngeal telescope. The images were then processed by the system and displayed on a video monitor. Normal tissue appeared green while malignant sites appeared reddish-brown. The autofluorescence imaging technique was compared to standard microlaryngoscopy in 108 patients with laryngeal pathologies (in 74 of whom malignancy was suspected). The acquired reflectance and fluorescence images of each lesion were assessed independently as malignant or not malignant by three ENT specialists who were familiar with the procedure but were not provided with clinical data or histopathological information concerning the lesion. The assessments of pathology were determined from the two imaging modalities and were compared to histopathological findings of the biopsy specimens taken from the lesion. The present study showed that autofluorescence imaging can be a useful complementary method to microlaryngoscopy for detecting and delineating laryngeal malignancies. If in the future, the device can be developed for use in an outpatient office, a significant improvement can be made for the early detection of laryngeal malignancies.