Abstract
Idiopathic inflammatory myopathies (IIMs), or autoimmune myositis, comprise four distinct disease subtypes: dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, and inclusion body myositis, as well as overlap myositis with other connective tissue diseases, including antisynthetase syndrome. Paraclinical investigations such as muscle biopsy, antibody testing, and muscle imaging are playing an increasingly important role in the diagnosis and treatment selection for these disease subtypes. Among these, muscle MRI is a non-invasive and fairly convenient method that allows examination of muscle inflammation, helping to suggest the diagnosis of the specific myositis subtype and guide the selection of the muscle biopsy site. We also conducted a study describing the pelvic and thigh muscle MRI characteristics of 11 Vietnamese patients with autoimmune myositis who presented at our hospital from September 2019 to February 2022. These patients had confirmed diagnoses based on clinical examination, electromyography, muscle enzymes (CK), histopathology, and antibody testing. We identified several notable MRI features in these myositis patients, such as edema and muscle atrophy, which may help in diagnosing each specific myositis subtype. Understanding the MRI characteristics of each distinct inflammatory myopathy subtype will provide additional useful information for diagnosis, prognosis, and selection of the most appropriate treatment for each individual patient.
