Double oscillating diffusion encoding and sensitivity to microscopic anisotropy

作者：Ianus Andrada; Shemesh Noam; Alexander Daniel C; Drobnjak Ivana

来源：Magnetic Resonance in Medicine, 2017, 78(2): 550-564.

DOI：10.1002/mrm.26393

• double diffusion encoding
• multiple diffusion encoding
• microscopic anisotropy
• microstructure
• double-PFG
• oscillating gradient spin echo
• OGSE
• MRI

PurposeTo introduce a novel diffusion pulse sequence, namely double oscillating diffusion encoding (DODE), and to investigate whether it adds sensitivity to microscopic diffusion anisotropy (mu A) compared to the well-established double diffusion encoding (DDE) methodology.
MethodsWe simulate measurements from DODE and DDE sequences for different types of microstructures exhibiting restricted diffusion. First, we compare the effect of varying pulse sequence parameters on the DODE and DDE signal. Then, we analyse the sensitivity of the two sequences to the microstructural parameters (pore diameter and length) which determine mu A. Finally, we investigate specificity of measurements to particular substrate configurations.
ResultsSimulations show that DODE sequences exhibit similar signal dependence on the relative angle between the two gradients as DDE sequences, however, the effect of varying the mixing time is less pronounced. The sensitivity analysis shows that in substrates with elongated pores and various orientations, DODE sequences increase the sensitivity to pore diameter, while DDE sequences are more sensitive to pore length. Moreover, DDE and DODE sequence parameters can be tailored to enhance/suppress the signal from a particular range of substrates.
ConclusionsA combination of DODE and DDE sequences maximize sensitivity to mu A, compared to using just the DDE method. Magn Reson Med 78:550-564, 2017. (c) 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

• 出版日期2017-8