Diffusion MRI basics

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Hi all,

In diffusion based MRI we have a set of gradients which is applied based on which the diffusion behavior in the brain is captured. So I read that there is a loss in the gradient signal in the direction of which diffusion of water is taking place. So signal loss in a particular signal indicates that fiber might be present in that direction. But what exactly leads to the signal loss in the direction of water diffusion ? Also what happens to a diffusion signal in areas where movement of water is restricted?

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I have figured this out. Water molecules diffuse freely along the direction of fibers but will be restricted if the movement of water molecules is perpendicular to the direction of the fibers. Consequently the diffusion signal gets attenuated if the water molecules move perpendicular to the direction of the fibers.

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