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Radiographic patterns of muscle involvement in the idiopathic inflammatory myopathies
Author(s) -
Day Jessica A.,
Bajic Nicholas,
Gentili Sheridan,
Patel Sandy,
Limaye Vidya
Publication year - 2019
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.26660
Subject(s) - polymyositis , medicine , inclusion body myositis , dermatomyositis , myositis , atrophy , inflammatory myopathy , myopathy , pathology , muscle atrophy , muscle biopsy , muscle weakness , thigh , edema , biopsy , anatomy
Abstract Introduction This study assesses the burden, distribution, and evolution of muscle inflammation and damage on MRI among subtypes of idiopathic inflammatory myopathy (IIM). Methods Musculoskeletal MRIs performed in 66 patients with IIM and 10 patients with non‐IIM between 2009 and 2016 were retrospectively graded for muscle edema, fatty replacement (FR), and atrophy. Results Immune‐mediated necrotizing myopathy (IMNM) patients had severe and extensive lower limb muscle edema, FR, and atrophy. The pelvic muscles and adductors were significantly more affected than in patients with dermatomyositis and polymyositis. Inclusion body myositis (IBM) was characterized by marked anterior thigh involvement, which stabilized or progressed at follow‐up imaging. Atrophy and FR grades improved over time in some non‐IBM IIM patients. Discussion Patients with IMNM and IBM have characteristic patterns of muscle MRI abnormalities that may allow them to be differentiated radiologically from other IIM subtypes. Muscle damage in non‐IBM IIM may be reversible.