Quantitative Evaluation of the Lumbar Multifidus Muscle by Shear Wave Dispersion in Healthy Adults: A Preliminary Study.

Abstract

To investigate the application value of shear wave dispersion (SWD) in healthy adults with the lumbar multifidus muscle (LMM), to determine the range of normal reference values, and to analyze the influences of factors on the parameter. Ninety-five healthy volunteers participated in the study, from whom 2-dimensional, shear wave elastography (SWE), and SWD images of the bilateral LMM were acquired in three positions (prone, standing, and anterior flexion). Subcutaneous fat thickness (SFH), SWE velocity, and SWD slope were measured accordingly for analyses. The mean SWD slope of the bilateral LMM in the prone position was as follows: left: 14.8 ± 3.1 (m/second)/kHz (female) and 13.0 ± 2.5 (m/second)/kHz (male); right: 14.8 ± 3.7 (m/second)/kHz (female) and 14.2 ± 3.4 (m/second)/kHz (male). In the prone position, there was a weak negative correlation between the bilateral LMM SWD slope of activity level 2 and level 1 (β = -1.5 (2 versus 1, left), -1.9 (2 versus 1, right), all P < .05), and between the left SWD slope of activity level 3 and level 1 (β = -2.3 [3 versus 1, left], P < .05). The correlation between SWE velocity and SWD slope value changed with the position: there was a weak positive correlation in the prone position (r = 0.3 [left], 0.37 [right], both P < .05), and a moderate positive correlation in the standing and anterior flexed positions (r = 0.49-0.74, both P < .001). SFH was moderately negatively correlated with bilateral SWD slope values in the anterior flexion (left: r = -0.4, P = .01; right: r = -0.7, P < .01). SWD imaging can be used as an adjunct tool to aid in the assessment of viscosity in LMM. Further, activity level, and position are influencing factors that should be considered in clinical practice.