title: Brain iron deposition and sequence characteristics in Parkinsonism: comparison of SWI, T₂* maps, T₂-weighted-, and FLAIR-SPACE.
abstract: OBJECTIVE
  To compare quantitatively T2- and T2*-based magnetic resonance imaging sequences in patients with symptoms of Parkinson disease and to evaluate the information content of those sequences regarding brain iron concentration.
  
  
  METHODS
  We imaged 51 patients with symptoms of Parkinson disease on 3-T magnetic resonance imaging with T2-weighted sampling perfection with application optimized contrasts using different flip-angle evolution (SPACE), fluid attenuation inversion recovery (FLAIR)-SPACE, susceptibility-weighted imaging (SWI), and parametric T2* sequence (MapIt). Signal analysis was performed in 22 regions of interest in the brain.
  
  
  RESULTS
  Correlations (r2 = 0.82...0.96) with brain iron concentration were excellent. Contrast and tissue separability ratios were best in the T2* maps and FLAIR-SPACE, respectively. Good correlations of contrast were reached between SWI and both T2-weighted SPACE and FLAIR-SPACE. Their relation to quantitative T2* values was reminiscent of a quadratic curve shape. However, separation into gray and white matter revealed a linear positive and negative correlation, respectively.
  
  
  CONCLUSIONS
  SWI showed potential in differentiating illnesses characterized by brain iron deposition. Closely similar information was given by T2-weighted SPACE and FLAIR-SPACE, whereas other sequence comparisons revealed dispersion from intersequence agreement.
authors.affiliation: Department of Radiology, Medical Imaging Centre, Tampere University Hospital, Tampere, Finland. maija.rossi@pshp.fi
authors.forename: Maija
authors.initials: M
authors.lastname: Rossi
authors.forename: Hanna
authors.initials: H
authors.lastname: Ruottinen
authors.forename: Irina
authors.initials: I
authors.lastname: Elovaara
authors.forename: Pertti
authors.initials: P
authors.lastname: Ryymin
authors.forename: Seppo
authors.initials: S
authors.lastname: Soimakallio
authors.forename: Hannu
authors.initials: H
authors.lastname: Eskola
authors.forename: Prasun
authors.initials: P
authors.lastname: Dastidar
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020734:Parkinsonian Disorders / Q000378:metabolism* / Q000473:pathology; D018709:Statistics, Nonparametric
chemical_list: D007501:Iron