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.
Drag the cross to see the image corresponding to low or high-spatial frequency information. A point in k-space encodes for data with the same orientation of the line passing through this point and the center of k-space.