Acute swelling of the limbs: magnetic resonance pictorial review of fascial and muscle signal changes

Objective: This pictorial review analyzes the magnetic resonance (MR) fasci al/muscular changes in 69 patients referred as emergencies with acute swell ing of the limbs (ASL) from various causes. Methods and material: A prospec tive MR imaging (MRI) study of 69 patients referred as emergencies for ASL was performed. Our population consisted of 45 patients with skin and soft-t issue infections (cellulitis and necrotizing fasciitis, and pyomyositis), s ix patients with soft-tissue inflammatory diseases (dermatomyositis, graft- versus-host disease), 11 patients with acute deep venous thrombosis, three patients with rhabdomyolysis, one patient with acute denervation and three other patients with rare diseases. Hematomas, tumorous or infectious bone i nvolvement and soft-tissue tumors were excluded. All studies included spin echo T1-weighted images and spin echo T2-weighted images. Gadolinium-enhanc ed spin echo T1-weighted images were obtained when an abscess was suspected on T2-weighted images. Selective fat-saturated T1- and T2-weighted sequenc es were also used. MRI analysis was performed to obtain a compartmentalized anatomical approach according to the location of signal abnormalities in s ubcutaneous fat, superficial and deep fascia and muscle. Results: In all pa tients with ASL, MRI demonstrated soft-tissue abnormalities involving subcu taneous fat, superficial fascia, deep fascia, on muscle. Although MR findin gs were non-specific, MRI appears sensitive for detecting subtle fascial an d muscle signal changes. Conclusions: In skin and soft-tissue infections, M RI can be helpful for therapeutic management by determining the depth of so ft-tissue involvement, particularly within fasciae and muscles, which is pa rtly related to the severity of cellulitis with severe systemic manifestati ons. MRI can also aid the surgeon in diagnosing abscesses. In inflammatory diseases, MRI can determine the best site for biopsy and also monitor thera peutic response. (C) 1999 Published by Elsevier Science Ireland Ltd. All ri ghts reserved.