Theoretical and experimental analysis of imaging gradients in DTI.
A comprehensive, analytical framework for MR- DTI is constructed in a linear algebra setup. The expressions describing the effects of imaging gradients show formulation ambiguities. Center-symmetric gradient schemes use no cross terms (NoCroT) in the calculations resulting, at least in theory, in the alleviation of the issue. When three estimation methods, all gradients, NoCroT and diffusion gradients only are compared based on experimental results it is observed that the full inclusion of imaging gradients can be detrimental and there is slight improvement with NoCroT over diffusion gradients only. It is concluded that design of new diffusion gradient schemes via optimization is necessary to decouple to the maximum extent the effects of imaging gradients.
Ozcan
Alpay
A
Biomedical MR Laboratory, Mallinckrodt Institute of Radiology, Washington University in Saint Louis, School of Medicine, Box 8227, St. Louis, MO 63110, USA. ozcan@zach.wustl.edu
D000465:Algorithms; D003198:Computer Simulation; D003952:Diagnostic Imaging / Q000379:methods; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D016018:Least-Squares Analysis; D015233:Models, Statistical; D008962:Models, Theoretical; D015203:Reproducibility of Results