Association between ultrasound measurements of muscle thickness, pennation angle, echogenicity and skeletal muscle strength in the elderly

Abstract

The increase of elderly in our society requires simple tools for quantification of sarcopenia in inpatient and outpatient settings. The aim of this study was to compare parameters determined with musculoskeletal ultrasound (M-US) with muscle strength in young and elderly patients. In this prospective, randomised and observer blind study, 26 young (24.2 ± 3.7 years) and 26 old (age 67.8 ± 4.8 years) patients were included. Muscle thickness, pennation angle and echogenicity of all muscles of musculus quadriceps were measured by M-US and correlated with isometric maximum voluntary contraction force (MVC) of musculus quadriceps. Reproducibility of M-US measurements as well as simple and multiple regression models were calculated. Of all measured M-US variables the highest reproducibility was found for measurements of thickness (intraclass correlation coefficients, 85-97%). Simple regression analysis showed a highly significant correlation of thickness measurements of all muscles of musculus quadriceps with MVC in the elderly and in the young. Multiple regression analysis revealed that thickness of musculus vastus medialis had the best correlation with MVC in the elderly. This study showed that measurement of muscle thickness, especially of musculus vastus medialis, by M-US is a reliable, bedside method for monitoring the extent of sarcopenia.

Trial registration: ClinicalTrials.gov NCT00933192.

Figures

Fig. 1

Transversal ultrasound images of musculus rectus femoris and musculus intermedius from a 28-year-old man (a) and a 69-year-old man (b). Maximal muscle thickness was measured separately from musculus rectus femoris and musculus intermedius at the widest distance between the upper and the deep fascias

Fig. 2

Longitudinal ultrasound images of musculus vastus lateralis and musculus intermedius of a 23-year-old man (a) and a 75 year-old-man (b). Pennation angles were measured between muscle fibres and the deep fascia of the muscle. The same images were used for echogenicity measurements by computer-assisted grey scale analysis

Fig. 3

Graphic presentation of the relationship between MVC and muscle thickness. Muscle thicknesses of musculus rectus femoris, musculus intermedius, musculus vastus lateralis and musculus vastus medialis were plotted against respective MVC of musculus quadriceps. The old patients are presented by open squares whereas the young patients are presented by closed squares. Pearson correlation coefficients as well as regression lines for the old (dotted line) and the young (straight line) patient group are shown