title: Whole-body MRI in adult inflammatory myopathies: Do we need imaging of the trunk?
abstract: OBJECTIVE
  To evaluate whether imaging of the trunk could be omitted in patients with inflammatory myopathies without losing diagnostic accuracy using a restricted whole-body magnetic resonance imaging (rWB-MRI) protocol.
  
  
  METHODS
  After approval by the institutional review board, this study was performed in 63 patients (male/female, 13/50; median age, 52 years; range, 20-81 years) with new-onset myopathic symptoms (group 1, n = 41) or previously diagnosed inflammatory myopathy (group 2, n = 22). After performing whole-body MRI (WB-MRI) at 3.0 Tesla, myositis and fatty atrophy were evaluated in different muscles by two independent radiologists. The intra-class correlation coefficient (ICC) was calculated to evaluate inter-observer reliability.
  
  
  RESULTS
  Acquisition time was 56:01 minutes for WB-MRI and 37:37 minutes (32.8 % shorter) for rWB-MRI. In group 1, 14 patients were diagnosed with inflammatory myopathy based on muscle biopsy. rWB-MRI and WB-MRI showed equal sensitivity (42.9 %) and specificity (100 %) for myositis, and showed equal sensitivity (71.4 %) and similar specificity (63.0 % and 48.1 %, respectively) for fatty atrophy. No myositis was found in the body trunk in any patient. Inter-observer reliability was between substantial and perfect (ICC, 0.77-1.00).
  
  
  CONCLUSIONS
  rWB-MRI showed diagnostic accuracy similar to WB-MRI for inflammatory myopathy at markedly reduced overall acquisition time.
  
  
  CONCLUSIONS
  • Whole-body MRI (WB-MRI) is a time-consuming imaging modality. • A shortened MRI protocol was evaluated for inflammatory myopathies. • The proposed protocol showed diagnostic accuracy similar to WB-MRI.
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. lukas.filli@usz.ch.
authors.forename: Lukas
authors.initials: L
authors.lastname: Filli
authors.affiliation: Division of Rheumatology, University Hospital Zurich, University of Zurich, Gloriastrasse 25, 8091, Zurich, Switzerland. britta.maurer@usz.ch.
authors.forename: Britta
authors.initials: B
authors.lastname: Maurer
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. andrei.manoliu@usz.ch.
authors.forename: Andrei
authors.initials: A
authors.lastname: Manoliu
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. gustav@andreisek.de.
authors.forename: Gustav
authors.initials: G
authors.lastname: Andreisek
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. roman.guggenberger@usz.ch.
authors.forename: Roman
authors.initials: R
authors.lastname: Guggenberger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000473:pathology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013909:Thorax / Q000473:pathology*; D051598:Whole Body Imaging / Q000379:methods*; D055815:Young Adult
keywords: Dermatomyositis; Inflammatory myopathy; Magnetic resonance imaging; Polymyositis; Whole-body