Quantifying Morphological Changes in Middle Trapezius With Ultrasonography and Histogram Matching for Participants With and Without Facioscapulohumeral Dystrophy

Objective: Echogenicity is a biomarker in facioscapulohumeral muscular dystrophy (FSHD). Currently, it is not possible to compare echogenicity values, derived using quantified muscle sonography capture, based on different equipment instrumentation settings. Image normalization, using histogram matching, could address this limitation. The aim of this study was to investigate the sensitivity of histogram matching, with trapezius muscle echogenicity values, in participants with and without FSHD. Materials and Methods: Sensitivity analysis of a single measurement timepoint case control study of participants with FSHD, using age- and gender-matched controls. Correlations between trapezius muscle echogenicity, muscle thickness, and shoulder range of movements were also completed. Results: Data were collected for 14 participants, seven with FSHD and seven controls. The cohort had a mean age of 41.6 years. The FSHD group echogenicity values (118.2) were higher than controls (42.3), respectively, as well as statistically significant ( p = .002). An overall variance of 6.2 (range = −2.9 to 15.4) was identified between the reference images. Echogenicity explained 81% of the variance in muscle thickness and 74% of the variance in range of movement muscle thickness was explained by 61% of the variance for range of movement. Conclusion: Histogram matching for comparison of echogenicity was required. Different reference images affect echogenicity values, but the variability was less than between group differences. Further longitudinal evaluation based on a larger sample of participants is needed.