Muscle echogenicity ratio can indicate severity of carpal tunnel syndrome

Introduction: The purpose of this study was to investigate the usefulness of the echogenicity (EI) ratio of the thenar to hypothenar muscle measured using ultrasonography in assessing the severity of carpal tunnel syndrome (CTS). Methods: Fifty-nine hands of 30 patients electrodiagnostically confirmed as having CTS were classified into 3 subgroups (mild, moderate, and severe). The EI of the thenar and hypothenar muscles was measured with ultrasonography, and the EI ratio was calculated in the patients and 13 normal participants (26 hands). Results: The average EI ratio was higher in the CTS group than in the control group. We also found a positive correlation between the severity of CTS and a high EI ratio measured with ultrasonography. Discussion: The EI ratio of the thenar to hypothenar muscle is a useful parameter that can indicate the severity of CTS.