In daily rheumatologic practice, patients often present with various muscular manifestations, such as myalgia, stiffness, and muscle weakness. These symptoms are characteristic of certain rheumatologic disorders, including myositis [1]. On the other hand, systemic inflammation associated with rheumatoid arthritis (RA) can lead to an accelerated loss of skeletal muscle mass and physical function, resulting in sarcopenia [2]. Additionally, several neuromuscular conditions such as muscular dystrophies and motor neuron diseases, can mimic myositis [3].

To address these complex manifestations, rheumatologists often perform detailed physical examinations along with laboratory tests, electromyography (EMG), and imaging modalities, including magnetic resonance imaging (MRI) [4]. While these tests often assist physicians in making a diagnosis and monitoring disease activity, they have certain limitations and contraindications that hinder their universal applicability.

Muscle ultrasound has been demonstrated to be a safe and effective imaging modality for various neuromuscular disorders, including myositis [5,6]. Its sensitivity for detecting myositis-related imaging abnormalities is reported to be high when compared to MRI [7], and it can identify distinct changes in ultrasound images in both acute and chronic myositis [6]. Additionally, echo intensity can be quantified and has been shown to correlate with muscle weakness, creatine kinase levels, and the number of inflammatory infiltrates [8]. Aside from myositis, ultrasound can also be used for the screening of sarcopenia in patients with RA [9] and other neuromuscular disorders that present with progressive weakness and myalgia, thereby mimicking myositis [4].

Despite its potential, muscle ultrasound has not been widely adopted among rheumatologists. This is primarily due to physician inexperience and challenges standardizing assessments of muscle ultrasound images [5,6]. Nevertheless, ultrasound has significant potential as a valuable point-of-care diagnostic and monitoring tool in clinical practice. In this review, we explore muscle ultrasound as a practical imaging modality for the assessment of muscle diseases in rheumatology clinics. We also discuss emerging ultrasound technologies and a novel semi-quantitative analysis for evaluating myositis.