title: Brain iron deficiency in idiopathic restless legs syndrome measured by quantitative magnetic susceptibility at 7 tesla.
abstract: Altered brain iron homeostasis with regional iron deficiency has been previously reported in several studies of restless legs syndrome (RLS) patients. Inconsistencies still exist, however, in the reported iron changes in different brain regions and different RLS phenotypes. The purpose of this study was to assess differences in brain iron concentrations between RLS patients and healthy controls and their relation to severity of disease and periodic limb movement during sleep (PLMS).
  
  
  
  Assessment of brain iron was done using quantitative magnetic susceptibility measurement, which has been shown to correlate well with the tissue iron content in brain's gray matter. Thirty-nine RLS patients and 29 age-matched healthy controls were scanned at 7 T. Magnetic susceptibilities in substantia nigra (SN), thalamus, striatum, and several iron-rich gray matter regions were quantified and compared with related clinical measures.
  
  
  
  Compared with healthy controls, RLS patients showed significantly decreased magnetic susceptibility in the thalamus and dentate nucleus. No significant difference was found in the SN between RLS patients and healthy controls, but a significant correlation was observed between magnetic susceptibility in SN and the PLMS measure.
  
  
  
  Using quantitative magnetic susceptibility as an in vivo indicator of brain iron content, the present study supports the general hypothesis of brain iron deficiency in RLS and indicates its possible link to PLMS.
authors.affiliation: F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA. Electronic address: xuli@mri.jhu.edu.
authors.forename: Xu
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Allen
authors.affiliation: Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Earley
authors.affiliation: F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, China.
authors.forename: Hongjun
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Tiana E
authors.initials: TE
authors.lastname: Cruz
authors.affiliation: F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Richard A E
authors.initials: RAE
authors.lastname: Edden
authors.affiliation: F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Barker
authors.affiliation: F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Peter C M
authors.initials: PCM
authors.lastname: van Zijl
mesh_terms: D005260:Female; D006801:Humans; D000090463:Iron Deficiencies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012148:Restless Legs Syndrome / Q000503:physiopathology*; D013378:Substantia Nigra / Q000378:metabolism*; D013788:Thalamus / Q000378:metabolism
keywords: Brain iron deficiency; Periodic limb movement during sleep; Quantitative susceptibility mapping; Restless legs syndrome