Disorders of muscle are common. Diagnostic modalities include electromyography and biopsy. While valuable, the approaches are qualitative and invasive – and not well-suited for surveillance. Accordingly, there remains a need for quantitative measures of muscle health for longitudinal use in research trials and clinical care.

As a painless bedside technology, EIT could help meet this need. In EIT, weak electrical currents are applied through electrodes positioned over the skin; resultant surface voltages are translated into cross-sectional images that show how impedance is distributed throughout a region of interest. These impedance maps can be numerically transformed to evaluate characteristics including conductivity, permittivity, and phase. In this ongoing study, we are evaluating a combined US-EIT system that simultaneously collects ultrasound images and impedance data.