Photo Credit: Wasan Tita
The following is a summary of “Magnetic Resonance Imaging Patterns Revealing Muscle Pathology and Clinical Features in Idiopathic Inflammatory Myopathies,” published in the February 2023 issue of Rheumatology by Shimoyama et al.
The exact link between MRI findings and muscle characteristics remains unclear despite using magnetic resonance imaging (MRI) to study Idiopathic inflammatory myopathies (IIMs).
Researchers conducted a retrospective study investigating the connection between muscle MRI findings, muscle pathology, and clinical features in patients with IIMs.
They examined new IIM patients through muscle MRI scans of their proximal upper and/or lower limbs. Various MRI patterns of muscle oedema were identified and compared with inflammatory cell infiltration sites in muscle biopsies. The frequency of MRI patterns was assessed within patient subgroups based on myositis-specific antibodies (MSAs) and the 2017 EULAR/ACR classification criteria. Univariate and multivariate analyses determined MRI findings’ ORs with clinical characteristics.
The results showed that 56/85 patients had muscle biopsies. Different patterns at biopsy sites like foggy, honeycomb, and fascial were linked to inflammatory cell infiltration in specific areas: endomysium (OR 11.9, P=0.005), perimysium (OR 6.0, P=0.014), and fascia (OR 16.9, P<0.001). Honeycomb and foggy patterns were seen in patients with certain antibodies and specific types of dermatomyositis or polymyositis. The honeycomb pattern was associated with malignancy (OR 6.87, P<0.001) and Gottron sign (OR 8.05, P=0.002), while the foggy pattern was linked to muscle weakness (OR 11.24, P=0.005). The dense dot pattern was also connected to dysphagia (OR 6.27, P=0.006) and malignancy (OR 8.49, P=0.002).
Investigators concluded that muscle MRI could potentially characterize muscle pathology, differentiate IIM subtypes, and predict clinical presentations.
Source: academic.oup.com/rheumatology/advance-article-abstract/doi/10.1093/rheumatology/keae125/7614640
