Show Summary Details
Page of

Anisotropic Diffusion: From the Apparent Diffusion Coefficient to the Apparent Diffusion Tensor 

Anisotropic Diffusion: From the Apparent Diffusion Coefficient to the Apparent Diffusion Tensor
Chapter:
Anisotropic Diffusion: From the Apparent Diffusion Coefficient to the Apparent Diffusion Tensor
Author(s):

Peter J. Basser

and Evren Özarslan

DOI:
10.1093/med/9780195369779.003.0006
Page of

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com). © Oxford University Press, 2016. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 16 December 2019

This chapter provides some conceptual underpinnings of diffusion tensor imaging (DTI). In particular, it explains isotropic and anisotropic diffusion and presents the definition of the apparent diffusion coefficient (ADC) and that of an analogous quantity, the apparent diffusion tensor (ADT). The underlying models and experimental designs used for diffusion nuclear magnetic resonance (NMR) and diffusion tensor NMR are compared. The chapter also describes information contained in the diffusion ellipsoid that one can use to characterize its size, shape, and orientation in diffusion tensor NMR. Intrinsic features of the ADT, such as the trace or mean ADC, the eigenvalues and eigenvectors of the ADT, and the fractional anisotropy (FA), are defined and described. The diffusion tensor NMR experiment can be further generalized to diffusion tensor MRI or DTI; in this context, the meaning of the b-matrix is explained. The notion of a diffusion tensor field is discussed, and DTI “tractography” is described in this context. Limitations of the Gaussian displacement model used in DTI are also addressed, along with new ways to extend the scope and applications of diffusion MRI methods to probe microstructural features not detectable by DTI.

Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Public users are able to search the site and view the abstracts for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.