title: Quantitative oxygenation venography from MRI phase.
abstract: OBJECTIVE
  To demonstrate acquisition and processing methods for quantitative oxygenation venograms that map in vivo oxygen saturation (SvO2 ) along cerebral venous vasculature.
  
  
  METHODS
  Regularized quantitative susceptibility mapping (QSM) is used to reconstruct susceptibility values and estimate SvO2 in veins. QSM with ℓ1 and ℓ2 regularization are compared in numerical simulations of vessel structures with known magnetic susceptibility. Dual-echo, flow-compensated phase images are collected in three healthy volunteers to create QSM images. Bright veins in the susceptibility maps are vectorized and used to form a three-dimensional vascular mesh, or venogram, along which to display SvO2 values from QSM.
  
  
  RESULTS
  Quantitative oxygenation venograms that map SvO2 along brain vessels of arbitrary orientation and geometry are shown in vivo. SvO2 values in major cerebral veins lie within the normal physiological range reported by (15) O positron emission tomography. SvO2 from QSM is consistent with previous MR susceptometry methods for vessel segments oriented parallel to the main magnetic field. In vessel simulations, ℓ1 regularization results in less than 10% SvO2 absolute error across all vessel tilt orientations and provides more accurate SvO2 estimation than ℓ2 regularization.
  
  
  CONCLUSIONS
  The proposed analysis of susceptibility images enables reliable mapping of quantitative SvO2 along venograms and may facilitate clinical use of venous oxygenation imaging.
authors.affiliation: Magnetic Resonance Imaging Group, Research Laboratory of Electronics, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: Audrey P
authors.initials: AP
authors.lastname: Fan
authors.forename: Berkin
authors.initials: B
authors.lastname: Bilgic
authors.forename: Louis
authors.initials: L
authors.lastname: Gagnon
authors.forename: Thomas
authors.initials: T
authors.lastname: Witzel
authors.forename: Himanshu
authors.initials: H
authors.lastname: Bhat
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Rosen
authors.forename: Elfar
authors.initials: E
authors.lastname: Adalsteinsson
mesh_terms: D000328:Adult; D002550:Cerebral Veins; D003198:Computer Simulation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000097:blood*
chemical_list: D010100:Oxygen
keywords: brain oxygenation; quantitative susceptibility; venography; venous oxygen saturation