Correlation Analysis between EIT-derived Parameters and Ultrasound-measured Muscle Thickness and CAS Characteristics

Dynamic and real-time monitoring of muscle mass is crucial for muscle function, physical function, and clinical disease diagnosis (sarcopenia, muscle atrophy, etc.). Electrical impedance tomography (EIT) provides a new option for muscle mass assessment and muscle tissue imaging, but the relationship between EIT-derived parameters and classic muscle mass characteristics has not been established. In this study, 18 healthy subjects were recruited, and the impedance (Z), resistance (R), and conductivity (σ) characteristics of thigh muscles were obtained using EIT equipment. The ultrasound (US) equipment was used to measure total muscle thickness (TMT) and total cross-sectional area (TCSA) of quadriceps and hamstrings, and then the correlation between EIT-derived parameters and ultrasound measurement characteristics was established. The results showed that R and Z were significantly negatively correlated with TMT (r = -0.62, p<0.05; r = -0.67, p<0.01), while σ was significantly positively correlated with TMT (r = 0.76, p<0.01); R and Z were significantly negatively correlated with TCSA (r = -0.59, p < 0.05; r = -0.63, p < 0.01), while σ was significantly positively correlated with TCSA (r = 0.65, p < 0.01). This work preliminarily verifies the potential of EIT to assess muscle mass and is expected to become a new tool for screening and auxiliary diagnosis of sarcopenia and muscle function decline in the community.