title: Aerodynamics, voice quality, and laryngeal image analysis of normal and pathologic voices.
abstract: OBJECTIVE
  The purpose of this review is to describe examinations of phonatory function and their relation to image analysis of the unilaterally immobile larynx. Special emphasis was placed on image analysis using three-dimensional endoscopic images produced from CT scans.
  
  
  RESULTS
  Developments in modern image processing technique have led to the quantification of various aspects of vocal fold vibration. Stroboscopic images of the vocal fold were digitized and, subsequently, the glottal gap area, amplitude, and degree of bowing were analyzed quantitatively in relation to phonatory function. Vocal fold vibration was observed with the aid of videokymography, during which images from a single transverse line can be recorded. Successive line images were shown in real time on a monitor, with the time dimension displayed in the vertical direction. This system enabled the assessment of left-right asymmetries, open quotient, propagation of mucosal waves, and forth. Three-dimensional endoscopic images derived from multislice CT scans provided a novel method for evaluating morphologic characteristics of the laryngeal lumen in relation to phonatory function. The combination of three-dimensional endoscopy and coronal reconstructed images supplemented stroboscopic findings exemplified by differences in vertical position and thickness between the vocal folds.
  
  
  CONCLUSIONS
  Depth information about the vocal fold as well as the presence of paradoxic movement of the affected vocal fold and overadduction of the healthy vocal fold during phonation should be taken into account when surgical intervention to improve hoarseness resulting from unilateral vocal fold immobility is performed. Phonatory function tests, videostroboscopy, and laryngeal image analysis are prerequisites to achieving this goal.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kumamoto University, Japan. yumoto@gpo.kumamoto-u.ac.jp
authors.forename: Eiji
authors.initials: E
authors.lastname: Yumoto
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007734:Kymography; D007828:Laryngoscopy; D010699:Phonation / Q000502:physiology; D010775:Photic Stimulation; D012123:Pulmonary Ventilation / Q000502:physiology*; D012016:Reference Values; D014057:Tomography, X-Ray Computed; D014584:User-Computer Interface; D014741:Video Recording; D014826:Vocal Cord Paralysis / Q000175:diagnosis* / Q000503:physiopathology; D014827:Vocal Cords / Q000503:physiopathology; D014832:Voice Disorders / Q000175:diagnosis* / Q000503:physiopathology; D014833:Voice Quality / Q000502:physiology*