Quantitative ultrasound of lower leg and foot muscles: Feasibility and reference values

Ultrasound is a non-invasive method to quantitatively measure various muscle parameters. Purpose of this study was to assess the feasibility of ultrasound of lower leg and foot muscles and to obtain reference values for muscle thickness (MT) and echo intensity (EI). Ultrasound measurements of leg and foot muscles were performed in 60 healthy adults. MT and EI were quantitatively determined for the abductor hallucis (AH), extensor digitorum brevis (EDB), extensor hallucis longus (EHL) and peroneus longus (PER) muscles. Influence of age, height, weight and sex was determined using a multiple linear regression analysis. All muscles except the AH could easily be visualized with ultrasound. EI tended to be increased above 60 years and MT was significantly higher in men compared to women, necessitating age- and sex-dependent reference values. This study shows that muscle ultrasound is capable of visualizing lower leg and foot muscles and reference values for MT and EI can be obtained. Future research will focus on the use of these reference values to evaluate muscle abnormalities caused by neuromuscular disorders like hereditary motor and sensory neuropathy.