As the slice data is collected it is slotted into a 2D representation called "K-space". K-space can get very difficult to understand but I'll just cover the key points you need to know.
Each column of k-space contains the data obtained during one frequency encoding step. Each row is filled in by repeating the phase-encoding steps.
- The point to understand is that each point in k-space contains information on the whole of the MR image.
- The centre of k-space contains the contrast information
- The periphery of k-space contains the fine detail