Quantitative oxygenation venography from MRI phase.
PURPOSE
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.


CONCLUSION
The proposed analysis of susceptibility images enables reliable mapping of quantitative SvO2 along venograms and may facilitate clinical use of venous oxygenation imaging.
['Fan|Audrey P|AP|', 'Bilgic|Berkin|B|', 'Gagnon|Louis|L|', 'Witzel|Thomas|T|', 'Bhat|Himanshu|H|', 'Rosen|Bruce R|BR|', 'Adalsteinsson|Elfar|E|']
D000328:Adult D002550:Cerebral Veins D003198:Computer Simulation D005260:Female D064368:Healthy Volunteers D006801:Humans D007089:Image Enhancement D007090:Image Interpretation, Computer-Assisted D021621:Imaging, Three-Dimensional D018810:Magnetic Resonance Angiography D008297:Male D010100:Oxygen
venography quantitative susceptibility brain oxygenation venous oxygen saturation