title: MTR variations in normal adult brain structures using balanced steady-state free precession.
abstract: BACKGROUND
  Magnetization transfer (MT) is sensitive to the macromolecular environment of water protons and thereby provides information not obtainable from conventional magnetic resonance imaging (MRI). Compared to standard methods, MT-sensitized balanced steady-state free precession (bSSFP) offers high-resolution images with significantly reduced acquisition times. In this study, high-resolution magnetization transfer ratio (MTR) images from normal appearing brain structures were acquired with bSSFP.
  
  
  METHODS
  Twelve subjects were studied on a 1.5 T scanner. MTR values were calculated from MT images acquired in 3D with 1.3 mm isotropic resolution. The complete MT data set was acquired within less than 3.5 min. Forty-one brain structures of the white matter (WM) and gray matter (GM) were identified for each subject.
  
  
  RESULTS
  MTR values were higher for WM than GM. In general, MTR values of the WM and GM structures were in good accordance with the literature. However, MTR values showed more homogenous values within WM and GM structures than previous studies.
  
  
  CONCLUSIONS
  MT-sensitized bSSFP provides isotropic high-resolution MTR images and hereby allows assessment of reliable MTR data in also very small brain structures in clinically feasible acquisition times and is thus a promising sequence for being widely used in the clinical routine. The present normative data can serve as a reference for the future characterization of brain pathologies.
authors.affiliation: Department of Neuroradiology, Institute of Radiology, University of Basel Hospital, Petersgraben 4, 4031 Basel, Switzerland. garciame@uhbs.ch
authors.forename: Meritxell
authors.initials: M
authors.lastname: Garcia
authors.forename: Monika
authors.initials: M
authors.lastname: Gloor
authors.forename: Oliver
authors.initials: O
authors.lastname: Bieri
authors.forename: Stephan G
authors.initials: SG
authors.lastname: Wetzel
authors.forename: Ernst-Wilhelm
authors.initials: EW
authors.lastname: Radue
authors.forename: Klaus
authors.initials: K
authors.lastname: Scheffler
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity