Supersonic shear imaging provides a reliable measurement of resting muscle shear elastic modulus

Abstract

The aim of the present study was to assess the reliability of shear elastic modulus measurements performed using supersonic shear imaging (SSI) in nine resting muscles (i.e. gastrocnemius medialis, tibialis anterior, vastus lateralis, rectus femoris, triceps brachii, biceps brachii, brachioradialis, adductor pollicis obliquus and abductor digiti minimi) of different architectures and typologies. Thirty healthy subjects were randomly assigned to the intra-session reliability (n = 20), inter-day reliability (n = 21) and the inter-observer reliability (n = 16) experiments. Muscle shear elastic modulus ranged from 2.99 (gastrocnemius medialis) to 4.50 kPa (adductor digiti minimi and tibialis anterior). On the whole, very good reliability was observed, with a coefficient of variation (CV) ranging from 4.6% to 8%, except for the inter-operator reliability of adductor pollicis obliquus (CV = 11.5%). The intraclass correlation coefficients were good (0.871 ± 0.045 for the intra-session reliability, 0.815 ± 0.065 for the inter-day reliability and 0.709 ± 0.141 for the inter-observer reliability). Both the reliability and the ease of use of SSI make it a potentially interesting technique that would be of benefit to fundamental, applied and clinical research projects that need an accurate assessment of muscle mechanical properties.

Reliable Protocol for Shear Wave Elastography of Lower Limb Muscles at Rest and During Passive Stretching

“…These results are close to those provided by Lacourpaille et al (2012), who found intra-operator repeatability lower than 6% and inter-operator reliability lower than 11.5%. Values measured by Lacourpaille et al (2012) were lower of about 1 kPa compared to those presented in this study at rest (GM: 2.99 vs 4.7, VL: 3.26 vs 4.5, RF: 3.23 vs 4.1). Both studies were performed on homogeneous population healthy young subjects.…”

“…This was accompanied by a measured increase in shear modulus which was observed during preliminary tests. A similar phenomenon was previously observed by Lacourpaille et al (2012), but such increase in modulus was eliminated by asking the subject to freely strech out and walk between each series of measurement.…”

“…An intra-day coefficient of variation of two subjects was estimated at 19.4% for GL and 15.7% for biceps brachii by Ringleb et al (2007). If intra-day variation is disregarded, SWE appeared slightly more reliable than magnetic resonance elastography, as noted by Lacourpaille et al (2012).…”

“…It has been shown that vastus medialis obliquus of pathologic patients appeared less stiff during contraction than healthy patients but no reliability study was performed. Lacourpaille et al (2012) evaluated the reliability of this technique in nine muscles and proposed to standardize the muscle length by controlling joint angles which were chosen to leave the muscle as slack as possible. These positions seemed to improved the reliability due to the range of muscle slack length, which allowed the shear modulus to remain constant under small angle variations between joints.…”

Non-invasive biomechanical characterization of intervertebral discs by shear wave ultrasound elastography: a feasibility study

“…Precision values were similar to those obtained in vitro in animal specimens (Vergari et al, 2014) (7 % repeatability in unloaded discs) and in vivo in muscles (Lacourpaille et al, 2012). Measurements in breast phantom have been previously performed with a slightly higher precision error of 0.5 m/s (corresponding to 0.82 kPa in Young's modulus) (Mun et al, 2013).…”