A variation of the (Half Fourier Acquisition Single Shot Turbo Spin Echo) HASTE sequence, whereat half of the image information is acquired after the first excitation pulse, and the half after the second excitation pulse. The acquired data are then interleaved into the raw data matrix. A long time to repetition (TR) is selected to allow the spin system to recover between excitation pulses and the dead time is used for additional slices. The length of the echo train is cut in half. Also more than 2 segments are possible.

The Mx and My data (digital MR signal) sampled and stored during data acquisition as a function of time and phase from an MRI sequence are called raw data. The horizontal axis is the frequency code, the vertical axis the phase code (of the protons).
Every point in the raw data matrix contains part of the information for the complete image. A point in the raw data matrix does not correspond to a point in the image matrix. The outer rows of the raw data matrix provide information regarding the borders and contours of the image, detailed structures, and also determine the resolution. This is also called k-space data.