Assessment of vocal fold mobility using dynamic magnetic resonance imaging and ultrasound in healthy volunteers

Purpose
To verify the value of dynamic magnetic resonance imaging (MRI) sequences, fast field echo (FFE), and balanced gradient echo (true fast imaging with steady-state free precession – TRUFI) in the evaluation of vocal fold mobility in healthy volunteers, against ultrasound examination (US) as the reference test.

Material and methods
Vocal fold mobility in 35 healthy volunteers (age 20-59 years, 20 women and 15 men) with no history of laryngeal disorders and neck surgeries was determined by means of US and MRI during normal breathing and phonation of the “hiiii” sound. US images were used to determine the glottic angles. During MRI two dynamic sequences, fast field echo and balanced gradient echo, were applied to determine the minimum and maximum values of the glottic angles, along with the rima glottidis area, separately for the right and left compartments. Due to differences in larynx anatomy, the abovementioned parameters were analysed separately for women and men.

Results
No significant differences were observed between the glottic angle values obtained during US and dynamic MRI (FFE and TRUFI sequences). Regardless of the dynamic MRI sequence used, a positive correlation was found between the maximum values of glottic angle and the rima glottidis area. This correlation was strong and statistically significant among men, but not in women.

Conclusions
Dynamic MRI of vocal folds using FFE and TRUFI sequence is an accurate method for the objective evaluation of rima glottidis width.