Objective: The purpose of this study was to prospectively identify the normal sonographic values of human true and false vocal cords.
Methods: In total, 229 healthy volunteers were divided into 8 groups according to their age and sex. High-frequency sonography was used to measure the length, width, and thickness of both true and false vocal cords. Measurements were compared between groups, and correlations with age were analyzed. Forty of the 229 volunteers also participated in reliability and reproducibility studies.
Results: The sonographic measurements had good reproducibility, with intraclass correlation coefficient ranges of 0.736 to 0.903 for interobserver reliability and 0.723 to 0.943 for intraobserver reliability. Measurements for the 3 parameters of both true and false vocal cords in male adults were greater than those in female adults (P < .001). The length, width, and thickness of true and false vocal cords in participants younger than 18 years were obviously correlated with age (r = 0.835-0.957; P < .001), but no significant correlation was found in the adult groups. The rates of visualization in male groups were significantly lower than those in female groups (P < .001) and gradually decreased with increasing age.
Conclusions: Both true and false vocal cords can be shown by high-frequency sonography, which can quantitatively measure both true and false vocal cords with good reliability and reproducibility.