The Association between Muscular Ultrasonographic Alterations and Clinical Symptoms in Patients with Inflammatory Myopathy

Purpose:Muscle biopsy is commonly used to diagnose inflammatory myopathies. We evaluated the ability of muscle ultrasound (MUS), a non-invasive and simple tool, to distinguish between healthy subjects and individuals with inflammatory myopathy.Methods:This study was conducted on 17 patients with recently diagnosed biopsy-proven inflammatory myopathies (12 dermatomyositis, five polymyositis) compared with 17 age- and gender-matched healthy control adults. All patients underwent clinical assessments, including manual muscle testing (MMT) and hand-held dynamometry, as well as MUS evaluations, including thickness and echointensity (EI) in predefined muscle groups.Results: The disease duration was 7 (interquartile range: 3-11) months. Except for biceps and gastrocnemius, the patients' muscles had significantly higher EI and lower thickness in comparison with the controls, The EI sum-score manifested the highest area under curve (AUC) in comparison with the sum-scores of other variables (EI vs. MMT: AUCs-difference = 0.18, p < 0.01; EI vs. dynamometry: AUCs-difference = 0.14, p = 0.02; EI vs. thickness: AUCs-difference = 0.25, p < 0.01).Conclusion:Echointensity of muscles differed significantly between healthy individuals and those with inflammatory myopathies and may potentially serve as a useful diagnostic biomarker.