Post-Processing of High-Speed Video-Laryngoscopic Images to Two-Dimensional Scanning Digital Kymographic Images

ABSTRACT

BACKGROUND AND OBJECTIVES: High-speed videolaryngoscopy (HSV) is the only technique that captures the true intra-cycle vibratory behavior of the vocal folds by capturing full images of the vocal folds. However, it has problems of no immediate feedback during examination, considerable waiting time for digital kymography (DKG), recording duration limited to a few seconds, and extreme demands for storage space. Herein, we demonstrate a new post-processing method that converts HSV images to two-dimensional digital kymography (2D-DKG) images, which adopts the algorithm of 2D videokymography (2D VKG). MATERIALS AND METHODS: HSV system was used to capture images of vocal folds. HSV images were post-processed in Kay image-process software (KIPS), and conventional DKG images were retrieved. Custom-made post-processing system was used to convert HSV images to 2D-DKG images. The quantitative parameters of the post-processed 2D-DKG images was validated by comparing these parameters with those of the DKG images. RESULTS: Serial HSV images for all phases of vocal fold vibratory movement are included. The images were converted by the scanning method using U-medical image-process software. Similar to conventional DKG, post-processed 2D DKG image from the HSV image can provide quantitative information on vocal fold mucosa vibration, including the various vibratory phases. Differences in amplitude symmetry index, phase symmetry index, open quotient, and close quotient between 2D-DKG and DKG were analyzed. There were no statistical differences between the quantitative parameters of vocal fold vibratory movement in 2D-DKG and DKG. CONCLUSION: The post-processing method of converting HSV images to 2D DKG images could provide clinical information and storage economy.