Whole-body MRI in the assessment of disease activity in juvenile dermatomyositis

Ann Rheum Dis. 2014 Jun;73(6):1083-90. doi: 10.1136/annrheumdis-2012-202915. Epub 2013 May 1.

Abstract

Objective: To compare whole-body MRI (WB-MRI) with clinical examination in the assessment of disease activity in juvenile dermatomyositis (JDM).

Methods: WB-MR images were obtained from 41 JDM patients and 41 controls using a 1.5 T MRI scanner and short τ inversion recovery sequences. 18 patients had follow-up WB-MRI. Muscle, subcutaneous tissue and myofascial signal abnormalities were scored in 36 muscular groups and on proximal and distal extremities. WB-MRI and clinical assessments were performed concurrently and results compared. Validation procedures included analysis of feasibility, reliability, construct validity, discriminative ability and responsiveness.

Results: WB-MRI revealed distal legs (26/41 patients) and forearm (19/41 patients) muscle inflammation undetected during clinical examination and allowed an accurate assessment of subcutaneous (23/41 patients) and myofascial involvement (13/41 patients). 27 patients showed a patchy distribution of muscle inflammation while in seven the abnormal hyperintense areas tended to be homogeneously distributed. The inter-reader agreement for muscular, subcutaneous and myofascial WB-MRI scores was excellent. Correlations between WB-MRI muscle score and disease activity measures were excellent (Manual Muscle Test: rs=-0.84, Childhood Myositis Assessment Scale: rs=-0.81). WB-MRI score was higher in JDM active patients when compared with the control group (pB<0.0001) and the inactive patients (pB=0.004), and showed an excellent responsiveness (standardised response mean=1.65). Follow-up WB-MRI showed resolution of inflammation in nine patients whereas clinical criteria for remission were satisfied in five.

Conclusions: WB-MRI provides additional information to clinical evaluation and represents a promising tool to estimate total inflammatory burden, tailor treatment and monitor its efficacy.

Keywords: Dermatomyositis; Disease Activity; Magnetic Resonance Imaging.

MeSH terms

  • Adolescent
  • Case-Control Studies
  • Child
  • Cohort Studies
  • Dermatomyositis / diagnosis*
  • Dermatomyositis / pathology
  • Fascia / pathology*
  • Feasibility Studies
  • Female
  • Humans
  • Inflammation / pathology
  • Magnetic Resonance Imaging / methods*
  • Male
  • Muscle, Skeletal / pathology*
  • Physical Examination*
  • Reproducibility of Results
  • Severity of Illness Index
  • Subcutaneous Tissue / pathology*
  • Whole Body Imaging*

Supplementary concepts

  • Amyopathic dermatomyositis