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Diffusion Tensor Imaging (DTI): a magnetic resonance imaging technique that uses single-shot echo-planar MRI pulse sequences which have been optimized to detect the diffusivity of water molecules in tissue. By inducing magnetic gradients in different non-colinear directions while a subject is in the scanner, a series of diffusion weighted images (DWIs) can be acquired. For each given gradient, the echo attenuation values (ie “intensities”) at each voxel can then be used to calculate the apparent diffusion coefficient (ADC). The set of ADCs for each voxel can be used in turn to calculate the diffusion tensor for that voxel, an ellipsoid which models the diffusion profile of water within that voxel. The eccentricity of the ellipsoid is known as the Fractional Anisotropy (FA); the mean of the three principle eigenvectors is known as the mean diffusivity (MD). Source&Credit: DTI Notes, Jesse Brown, UCLA

Diffusion Tensor Imaging (DTI): a magnetic resonance imaging technique that uses single-shot echo-planar MRI pulse sequences which have been optimized to detect the diffusivity of water molecules in tissue. By inducing magnetic gradients in different non-colinear directions while a subject is in the scanner, a series of diffusion weighted images (DWIs) can be acquired. For each given gradient, the echo attenuation values (ie “intensities”) at each voxel can then be used to calculate the apparent diffusion coefficient (ADC). The set of ADCs for each voxel can be used in turn to calculate the diffusion tensor for that voxel, an ellipsoid which models the diffusion profile of water within that voxel. The eccentricity of the ellipsoid is known as the Fractional Anisotropy (FA); the mean of the three principle eigenvectors is known as the mean diffusivity (MD).

Source&Credit: DTI Notes, Jesse Brown, UCLA

Scientists in Ohio and France have explained some strange atomic behavior, and made a discovery that could ultimately make MRI images sharper. This graphic depicts the quantum mechanical principal of super-adiabaticity, which was responsible for the behavior of atoms in some nuclear magnetic resonance experiments. If the trajectory of the atoms during an experiment were mapped on a globe, then the purpose of an adiabatic experiment is to move the atoms being studied from one point on the globe to another, slowly, and following a very carefully designed path (gray line). With super-adiabaticity, the atoms follow a different, sometimes, wildly different path (orange line), but still end up at the right destination. Credit: Philip Grandinetti, Ohio State University. Source, Departments Of Chemistry and Biochemistry, Ohio State University.

Scientists in Ohio and France have explained some strange atomic behavior, and made a discovery that could ultimately make MRI images sharper. This graphic depicts the quantum mechanical principal of super-adiabaticity, which was responsible for the behavior of atoms in some nuclear magnetic resonance experiments. If the trajectory of the atoms during an experiment were mapped on a globe, then the purpose of an adiabatic experiment is to move the atoms being studied from one point on the globe to another, slowly, and following a very carefully designed path (gray line). With super-adiabaticity, the atoms follow a different, sometimes, wildly different path (orange line), but still end up at the right destination.

Credit: Philip Grandinetti, Ohio State University.

Source, Departments Of Chemistry and Biochemistry, Ohio State University.