Practical utilization of sonography for the assessment of muscle diseases in rheumatology

Muscular manifestations are common complaints encountered in daily rheumatology practice. Magnetic resonance imaging and electromyography are employed to evaluate muscular manifestations associated with myositis and other rheumatologic diseases, but both have limitations that hinder their universal applicability. Ultrasound, on the other hand, has been increasingly used given its utility as a point-of-care tool. There is increasing data that show it is a safe and sensitive tool for screening for myositis. Changes in ultrasound images differ between acute and chronic myositis, and echo intensity has been shown to correlate with muscle strength as well as the number of inflammatory cell infiltrates observed in histopathological analysis. Additionally, it can evaluate non-inflammatory muscular conditions, such as muscular dystrophy, sarcopenia, and certain neurologic disorders that mimic myositis. Despite its potential, its use in clinical practice remains limited due to a lack of physician experience and challenges associated with standardizing and optimizing muscle assessment. This review provides updated knowledge on muscle ultrasound as a practical imaging modality for the evaluation of myositis and other rheumatologic diseases. It discusses settings, techniques, and different assessment methods that will aid in its deployment in clinical practice.