Speed of sound ultrasound (SoS)

Abstract

Objectives

To measure speed of sound (SoS) with a novel hand-held ultrasound technique as a quantitative indicator for muscle loss and fatty muscular degeneration.

Methods

Both calf muscles of 11 healthy, young females (mean age 29 years), and 10 elderly females (mean age 82 years) were prospectively examined with a standard ultrasound machine. A flat Plexiglas® reflector, on the opposite side of the probe with the calf in between, was used as timing reference for SoS (m/s) and ΔSoS (variation of SoS, m/s). Handgrip strength (kPA), Tegner activity scores, and 5-point comfort score (1 = comfortable to 5 = never again) were also assessed. Ultrasound parameters (muscle/adipose thickness, echo intensity) were measured for comparison.

Results

Both calves were assessed in less than two minutes. All measurements were successful. The elderly females showed significantly lower SoS (1516 m/s, SD17) compared to the young adults (1545 m/s, SD10; p < 0.01). The ΔSoS of elderly females was significantly higher (12.2 m/s, SD3.6) than for young females (6.4 m/s, SD1.5; p < 0.01). Significant correlations of SoS with hand grip strength (r = 0.644) and Tegner activity score (rs = 0.709) were found, of similar magnitude as the correlation of hand grip strength with Tegner activity score (rs = 0.794). The average comfort score of the elderly was 1.1 and for the young adults 1.4. SoS senior/young classification (AUC = 0.936) was superior to conventional US parameters.

Conclusions

There were significant differences of SoS and ΔSoS between young and elderly females. Measurements were fast and well tolerated. The novel technique shows potential for sarcopenia quantification using a standard ultrasound machine.

Key Points

• Speed of sound ultrasound: a novel technique to identify sarcopenia in seniors.

• Measurements were fast and well tolerated using a standard ultrasound machine.

• The novel technique shows potential for sarcopenia quantification.