Gradients and spatial frequency

How and when the MR signals are mapped into the k-space cause great differences in the spatial, temporal and contrast resolution of the resulting MR images.

The location of the datas in k-space depends on the net strength and duration of the phase encoding gradient and frequency encoding gradient :

• A low-amplitude or short-duration gradient event encodes low-spatial-frequency information
• A high-amplitude or long-duration gradient event encodes high-spatial-frequency information.

The low-spatial-frequency informations are mapped near the center of k-space and the high-spatial-frequency informations are mapped to the periphery of k-space.