Reliability of Shear Wave Elastography for the Assessment of Gastrocnemius Fascia Elasticity in Healthy Individual

Abstract

The mechanical properties of deep fascia (i.e. an index of stiffness) strongly affect the development of muscle pathologies, and muscular actions, such as compartment syndromes. Actually, a clear understanding of the mechanical characterization of muscle deep fascia still lacks. The present study focuses on examining the reliability of ultrasonic shear wave elastography device (USWE) in quantifying the shear modulus of gastrocnemius fascia in healthy individual and the device’s abilities to examine the shear modulus of gastrocnemius deep fascia during ankle dorsiflexion. Twenty-one healthy males participated in the study (age: 21.48±1.17 years). The shear modulus of the medial gastrocnemius fascia (MGF) and lateral gastrocnemius fascia (LGF) were quantified at different angles using USWE during passive lengthening. The operators took turns to measure each subject’s MGF and LGF over 1-hour period and by operator B with a 2-hour interval. In the intra-operator test, the same subjects participated at the same time 5 days later. The intra-rater [ Intra-class correlation coefficient (ICC) = 0.846-0.965)] and inter-rater (ICC = 0.877-0.961) reliabilities for measuring the shear modulus of the MGF and LGF were rated as both excellent, and the standard error in measurement (SEM) was 3.49 kPa, the minimal detectable change (MDC) was 9.68 kPa. Regardless of the ankle angle, the shear modulus of the LGF were significant greater than that of the MGF (p < 0.001). The significant increase in the shear modulus both of the MGF and LGF were observed at neutral position compared to the relaxed position. This results indicate that the USWE is a technique to assess the shear modulus of gastrocnemius fascia and detect its dynamic changes during ankle dorsiflexion. USWE can be used for biomechanical study and intervention experiments of deep fascia.