en Clinical Neuroscience Clinical Neuroscience Original Original <strong>Introduction</strong>: Muscle biopsy is commonly used to diagnose inflammatory myopathies. We evaluated the ability of muscle ultrasound, a non-invasive and simple tool, to distinguish between healthy subjects and patients with inflammatory myopathy.<br> <strong>Methods</strong>: This study was conducted on 17 patients recently diagnosed with biopsy inflammatory myopathies (12 dermatomyositis, 5 polymyositis) compared with 17 age- and gender-matched healthy control adults. All patients underwent clinical assessments, including manual muscle testing, hand-held dynamometry, and muscle ultrasound evaluations, including thickness and echo intensity in predefined muscle groups.&nbsp;<br> <strong>Results</strong>: The disease duration was seven months (interquartile range: 3 to 11 months). Except for the biceps and gastrocnemius, patients&rsquo; muscles had significantly higher echo intensity and lower thickness than the control group. The echo intensity sum-score manifested the highest area under the curve compared to the sum-scores of other variables (echo intensity vs manual muscle testing: Area under curves-difference=0.18, P<0.01; echo intensity vs dynamometry: Area under curves-difference=0.14, P=0.02; echo intensity vs thickness: Area under curves-differences-difference=0.25, P<0.01).&nbsp;<br> <strong>Conclusion</strong>: The echo intensity of muscles differed significantly between healthy individuals and patients with inflammatory myopathies and may serve as a useful diagnostic biomarker.&nbsp; Ultrasonography, Myositis, Case-control studies, Sensitivity and specificity 675 686 http://bcn.iums.ac.ir/browse.php?a_code=A-10-3567-1&slc_lang=en&sid=1 Farzad Fatehi fatehifa@gmail.com 13700319475328460046686 13700319475328460046686 Yes Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Parisa Khaghani dr.parisakhaghani@gmail.com 13700319475328460046687 0009-0000-6304-1086 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Ali Asghar Okhovat a-okhovat@sina.tums.ac.ir 13700319475328460046688 13700319475328460046688 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Kamyar Moradi kamyarmoradi74@gmail.com 13700319475328460046689 13700319475328460046689 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Farzad Teimouri teymouri.farzad@gmail.com 13700319475328460046690 0009-0003-2279-7217 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Mahsa Mortaja m.mortaja92@gmail.com 13700319475328460046691 0009-0006-6388-4298 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Mahsa Layegh layegh.mahsa@gmail.com 13700319475328460046692 0009-0008-3622-9954 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Akram Panahi akram.panahii61@gmail.com 13700319475328460046693 13700319475328460046693 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. Shahriar Nafissi s_nafissi@yahoo.com 13700319475328460046694 13700319475328460046694 No Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.