Imaging findings of scleroderma-associated myopathy: A systematic literature review

Systemic sclerosis (SSc) affects skeletal muscle directly, with SSc-associated myopathy (SSc-myopathy) increasingly recognised as a distinct immune-mediated myopathy. Manual muscle testing and creatine kinase (CK) are insensitive diagnostic tools for SSc-myopathy. We aimed to evaluate the role of imaging in SSc-myopathy diagnosis.

A systematic search of MEDLINE(Ovid), Pubmed, and EMBASE databases was performed to identify studies of ≥10 SSc patients that reported skeletal muscle imaging results. Eligibility criteria were defined a priori. Risk of bias assessment was performed using the National Heart, Lung and Blood Institute (NHLBI) quality assessment tool. Descriptive summaries were used to present data owing to inter-study heterogeneity.

Of 2426 studies identified, 17 articles met the inclusion criteria. Imaging modalities varied, but magnetic resonance imaging (MRI) was the most commonly applied imaging technique (n = 9 studies). Abnormalities on MRI were reported in 38-100 % of patients and included muscle oedema, atrophy, and fatty infiltration. Changes were observed in skeletal muscles (n = 14 studies), axial muscles (n = 1), masseter muscle (n = 1), and accessory respiratory muscles (n = 2). Blood oxygenation level-dependent MRI, dynamic contrast-enhanced ultrasound, and scintigraphic evaluation have each been used to assess skeletal muscle perfusion. A lack of correlation between creatine kinase, clinical weakness, and imaging findings was consistently reported. We were unable to identify any distinct imaging patterns or relationship between imaging and histopathological skeletal muscle abnormalities owing to limited data available.

Imaging detects inflammatory, atrophic, and vasculopathic changes in the skeletal musculature of SSc patients. The discordance between clinical assessment and imaging findings underscores the potential role for muscle imaging to both screen and diagnose SSc-myopathy.