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Diffusion-weighted and diffusion tensor imaging of the brain, made easy.

Huisman TA - Cancer Imaging (2010)

Bottom Line: In addition, DWI/DTI allows exploring the microarchitecture of the brain.A detailed knowledge of the basics of DWI/DTI is mandatory to better understand pathology encountered and to avoid misinterpretation of typical DWI/DTI artifacts.This article reviews the basic physics of DWI/DTI exemplified by several classical clinical cases.

View Article: PubMed Central - PubMed

Affiliation: Division Pediatric Radiology, Johns Hopkins Hospital, Baltimore, MD 21287-0842, USA. thuisma1@jhmi.edu

ABSTRACT
Diffusion-weighted and diffusion tensor imaging (DWI/DTI) has revolutionized clinical neuroimaging. Pathology may be detected earlier and with greater specificity than with conventional magnetic resonance imaging sequences. In addition, DWI/DTI allows exploring the microarchitecture of the brain. A detailed knowledge of the basics of DWI/DTI is mandatory to better understand pathology encountered and to avoid misinterpretation of typical DWI/DTI artifacts. This article reviews the basic physics of DWI/DTI exemplified by several classical clinical cases.

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Anisotropic diffusion (a) resembles a three-dimensional ellipsoid in space with predominant diffusion of molecules along the main axis of the ellipsoid and restricted diffusion perpendicular to the ellipsoid. Isotropic diffusion (b) can be represented by a sphere with equal diffusion in all directions in space. The arrows represent the motion of individual molecules.
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Figure 3: Anisotropic diffusion (a) resembles a three-dimensional ellipsoid in space with predominant diffusion of molecules along the main axis of the ellipsoid and restricted diffusion perpendicular to the ellipsoid. Isotropic diffusion (b) can be represented by a sphere with equal diffusion in all directions in space. The arrows represent the motion of individual molecules.

Mentions: Diffusion is however a three-dimensional phenomenon with a direction and shape. The three-dimensional shape and magnitude of diffusion differ between various brain structures. The microstructural architecture as well as physiologic factors influence the diffusion of water molecules within the brain. Diffusion in white matter tracts is, for example, predominantly along the direction parallel to the long axis of tracts and limited in the direction perpendicular to the tract. This directional diffusion can be graphically represented as an ellipsoid or cigar, and is known as anisotropic diffusion (Fig. 3a). When the degree of diffusion is equal in all directions in space such as in CSF, where no cell membranes limit diffusion, the three-dimensional shape of diffusion can be graphically represented by a sphere and is known as isotropic diffusion (Fig. 3b).Figure 3


Diffusion-weighted and diffusion tensor imaging of the brain, made easy.

Huisman TA - Cancer Imaging (2010)

Anisotropic diffusion (a) resembles a three-dimensional ellipsoid in space with predominant diffusion of molecules along the main axis of the ellipsoid and restricted diffusion perpendicular to the ellipsoid. Isotropic diffusion (b) can be represented by a sphere with equal diffusion in all directions in space. The arrows represent the motion of individual molecules.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2967146&req=5

Figure 3: Anisotropic diffusion (a) resembles a three-dimensional ellipsoid in space with predominant diffusion of molecules along the main axis of the ellipsoid and restricted diffusion perpendicular to the ellipsoid. Isotropic diffusion (b) can be represented by a sphere with equal diffusion in all directions in space. The arrows represent the motion of individual molecules.
Mentions: Diffusion is however a three-dimensional phenomenon with a direction and shape. The three-dimensional shape and magnitude of diffusion differ between various brain structures. The microstructural architecture as well as physiologic factors influence the diffusion of water molecules within the brain. Diffusion in white matter tracts is, for example, predominantly along the direction parallel to the long axis of tracts and limited in the direction perpendicular to the tract. This directional diffusion can be graphically represented as an ellipsoid or cigar, and is known as anisotropic diffusion (Fig. 3a). When the degree of diffusion is equal in all directions in space such as in CSF, where no cell membranes limit diffusion, the three-dimensional shape of diffusion can be graphically represented by a sphere and is known as isotropic diffusion (Fig. 3b).Figure 3

Bottom Line: In addition, DWI/DTI allows exploring the microarchitecture of the brain.A detailed knowledge of the basics of DWI/DTI is mandatory to better understand pathology encountered and to avoid misinterpretation of typical DWI/DTI artifacts.This article reviews the basic physics of DWI/DTI exemplified by several classical clinical cases.

View Article: PubMed Central - PubMed

Affiliation: Division Pediatric Radiology, Johns Hopkins Hospital, Baltimore, MD 21287-0842, USA. thuisma1@jhmi.edu

ABSTRACT
Diffusion-weighted and diffusion tensor imaging (DWI/DTI) has revolutionized clinical neuroimaging. Pathology may be detected earlier and with greater specificity than with conventional magnetic resonance imaging sequences. In addition, DWI/DTI allows exploring the microarchitecture of the brain. A detailed knowledge of the basics of DWI/DTI is mandatory to better understand pathology encountered and to avoid misinterpretation of typical DWI/DTI artifacts. This article reviews the basic physics of DWI/DTI exemplified by several classical clinical cases.

Show MeSH