Quantitative evaluation of gastrocnemius medialis mass in patients with chronic heart failure by gray-scale ultrasound and shear wave elastography

In this study, we examined the correlation between muscle ultrasound and muscle structure. Echo intensity (EI) of 14 muscles of two golden retriever muscular dystrophy dogs was correlated to the percentage interstitial fibrous tissue and fat in muscle biopsy. A significant correlation between interstitial fibrous tissue and EI was found (r = 0.87; p < 0.001). The separate influence of interstitial fat on muscle EI could not be established as only little fat was present. We conclude that fibrous tissue causes increased muscle EI. The high correlation between interstitial fibrous tissue and EI makes ultrasound a reliable method to determine severity of structural muscle changes.

Enhanced echo intensity (EI) on an ultrasound image of skeletal muscle indicates changes in muscle quality, including increases in intramuscular fibrous and adipose tissues. However, it is not known whether muscle quality assessed from the EI of computer-aided gray-scale analysis of an ultrasound image is associated with the muscle strength or body composition of a subject. The objectives of this study were to investigate whether muscle quality assessed from EI measured using gray-scale analysis is associated with muscle strength independently of age or muscle thickness (MT), and to examine the relationship between muscle EI and body composition. Ninety-two healthy women with a mean age of 70.4 ± 5.5 years (range, 51-87 years) dwelling in Kyoto, Japan, participated in the study. The MT, subcutaneous fat thickness (FT), and EI of the quadriceps femoris on the right extremity were assessed from transverse ultrasound images. Knee extensor isometric strength was used as a measure of the quadriceps femoris muscle strength. EI was significantly correlated with quadriceps strength independently of age or MT, and stepwise regression analysis revealed that MT and EI were independently associated with quadriceps strength. Importantly, EI showed no significant correlations with FT, percentage of body fat (%BF), or body mass index (BMI), while FT, BMI, and %BF did not significantly influence muscle strength. These data suggest that muscle quantity (i.e., MT) and muscle quality assessed from EI measured using computer-aided gray-scale analysis independently contribute to muscle strength in middle-aged and elderly persons.

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.