K-space MRI ppt

The individual points (kx,ky) in k-space do not correspond one-to-one with individual pixels (x,y) in the image. Each k-space point contains spatial frequency and phase information about every pixel in the final image. Conversely, each pixel in the image maps to every point in k-space .

The periphery of k-space contains high spatial frequency information (edges, details, sharp transitions). The cells of k-space are commonly displayed on rectangular grid with principal axes kx and ky.

The center of the echo (and hence largest values) occur near the middle of each row of k-space. Cartesian (line-by-line) filling of k-space . In 2DFT imaging, each row in k-space corresponds to the echo data obtained from a single application of the phase-encoding gradient.

By definition, the value of k-space at a particular kx, ky can be determined by performing two steps: (1) multiplying the image by cos(k xx + k yy) and then (2) summing the value of all the signal across the entire image . There are two steps to getting the Fourier transform of a tissue slice, that is, k-space.