Diffusion-weighted MR imaging with turbo-flash

This paper reports on diffusion imaging using spin-warp techniques which suffers from phase-encoding artifacts due to gross patient motion and brain pulsation. A diffusion-sensitive preparation pulse preceding a Turbo fast low-angle shot (FLASH) sequence overcomes this problem. A driven equilibrium Fourier transform (DEFT) pulse converts the spin-echo signal into longitudinal magnetization, which is used by the subsequent fast FLASH sequence. The application of additional gradients balanced with respect to the 180 degrees pulse leads to spin dephasing in the case of diffusion as well as motion. The DEFT scheme leads to a modulation of the transverse and longitudinal magnetization in the case of diffusion and, therefore, to intensity modulations in the image that can be removed by the application of phase-cycling methods to the DEFT pulse