Magnetic resonance imaging to assess the water environment of laryngeal tissues

Effective treatments for voice disorders require an understanding of vocal fold hydration and how it changes in normal and pathological states. To achieve this goal, noninvasive assessment of the vocal fold water environment is necessary. We describe the development of an MRI-based method to quantify the relative variation in water content of laryngeal tissues, especially the vocal folds. The T2 relaxation value, a measure sensitive to tissue water content, was calculated from multiecho, spin echo sequences that were acquired in 4 healthy participants. A vial of doped water (phantom) was imaged alone and then placed on the neck over the left thyroid lamina. No significant differences for the phantom or tissue measures were found with repeated assessments within or across days, and no significant dependence on left/right side tissues was observed. The phantom showed a maximum average T2 difference of .92 ms (1.10% change) over repeated images when secured to the neck, 0.21 ms (1.86% change) when imaged alone. Average maximum variability for the vocal fold (1.34% change), subcutaneous fat (4.23% change), and strap muscle complex (2.35% change) was greater than that of the vial, potentially due to heterogeneous physiology and respiratory movement. These relatively small errors may allow detection of large water changes in laryngeal tissues.