Abstract
Acquisition parameters play a crucial role in Diffusion Tensor Imaging (DTI), as they have a major impact on the values of scalar measures such as Fractional Anisotropy (FA) or Mean Diffusivity (MD) that are usually the focus of clinical studies based on white matter analysis. This paper presents an analysis on the impact of the variation of several acquisition parameters on these scalar measures with a novel double focus. First, a tractography-based approach is employed, motivated by the significant number of clinical studies that are carried out using this technique. Second, the consequences of simultaneous changes in multiple parameters are analyzed: number of gradient directions, b-value and voxel resolution. Results indicate that the FA is most affected by changes in the number of gradients and voxel resolution, while MD is specially influenced by variations in the b-value. Even if the choice of a tractography algorithm has an effect on the numerical values of the final scalar measures, the evolution of these measures when acquisition parameters are modified is parallel.
Highlights
IntroductionDiffusion Magnetic Resonance Imaging (dMRI) is an MRI imaging technique that allows the quantification of the diffusivity of water molecules within the tissue, providing information about the organization of the white matter of the brain and the orientation of its fiber tracts [1]
Diffusion Magnetic Resonance Imaging is an MRI imaging technique that allows the quantification of the diffusivity of water molecules within the tissue, providing information about the organization of the white matter of the brain and the orientation of its fiber tracts [1]. dMRI has gathered an extraordinary interest among the scientific community during the last years due to the relationships found between a number of neurological and neurosurgical pathologies and alterations in the white matter as revealed by an increasing number of dMRI studies [2,3,4,5]
Four fiber-related measures were analyzed: number of fibers obtained by the tractography algorithm, average length of the fiber tracts in each bundle, total volume occupied by the tracts of each bundle and overlapping volume between reconstructions
Summary
Diffusion Magnetic Resonance Imaging (dMRI) is an MRI imaging technique that allows the quantification of the diffusivity of water molecules within the tissue, providing information about the organization of the white matter of the brain and the orientation of its fiber tracts [1]. The most popular model of the diffusion profile is based on the Gaussian assumption, which allows the diffusion to be modeled with a single covariance matrix, namely the second order diffusion tensor. This technique is known as Diffusion Tensor Imaging (DTI) and requires measurements at least six different diffusion directions. It is today feasible to PLOS ONE | DOI:10.1371/journal.pone.0137905 October 12, 2015
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
