Physics, Techniques and Procedures

Dephasing

process which occurs whenever a microscopic or macroscopic magnetic field gradient exists in MR imaging. In a field gradient, spins within an imaged voxel lose phase coherence according to the Larmor equation. Dephasing gives rise to many wanted and unwanted effects in MR imaging and is at the basis of flow related dephasing and phase-related flow effects. Dephasing by the application of spoiler gradients can also be used to destroy any remaining in-plane magnetization in a gradient echo pulse sequence and strong dephasing gradients are used when applying diffusion imaging.

GvS