In vivo morphological and functional evaluation of the lateral pterygoid muscle: a diffusion tensor imaging study

Objective:To explore the feasibility of morphological and functional evaluation of the lateral pterygoid muscle (LPM) by diffusion tensor imaging (DTI) in vivo.Methods:30 healthy volunteers underwent DTI with the jaw in the rest position, opening and clenching. Diffusion parameters of the superior head of the LPM (SHLP) and the inferior head of the LPM (IHLP) at different jaw positions were calculated.Results:When the jaw was in the rest position, λ3 of the SHLP was significantly lower than that of the IHLP; fractional anisotropy (FA) value of the SHLP was significant higher than that of the IHLP. There was no significant difference in λ1, λ2 and apparent diffusion coefficient (ADC) value. During jaw opening, there was significant increase of all three eigenvalues and ADC value, and significant decrease of FA value both at the SHLP and IHLP. Clenching caused a significant increase in the ADC and all three eigenvalues, and caused a significant decrease of FA at the SHLP. However, at the IHLP, the variation...