Ultrasound strain imaging in assessment of false vocal folds in adults: A feasibility study

The aim of the study is to investigate the feasibility of ultrasound strain imaging (USI) in assessing magnitude and symmetry of false vocal folds (FVF) deformation as a quantitative marker for estimating FVF movement.

From October 2016 to July 2017, we performed USI of FVF in 44 adults [33 healthy controls and 11 subjects with unilateral vocal fold motion impairment (VFMI), 17 men and 27 women, mean age 43 years]. Real time ultrasound data of FVF in different configuration (abduction and adduction) was acquired through transcutaneous anterior-mid neck. Peak to valley strain (strain magnitude of maximum to minimum) representing the largest FVF deformation was estimated using 2-D speckle tracking. We developed peak to valley strain index [(Peak to valley strain _right - Peak to valley strain _left)/Peak to valley strain _maximum] to assess the symmetry of FVF deformation.

The difference in peak to valley strain between left and right FVF was significant in subjects with VFMI, whereas it was not in healthy controls. The peak to valley strain index was small (≤0.25) in symmetric FVF deformation in healthy controls whereas it was large (≥0.53) in asymmetric FVF deformation in subjects with VFMI. The area under receiver operating characteristics for peak to valley strain index in the determining asymmetric FVF deformation was 1.

Our results suggest that USI seems feasible to quantify both magnitude and symmetry of FVF deformation in adults. Further validation of USI in assessing VFMI is warranted.