Diffusion tensor mapping of the human brain using single-shot line scan imaging.

A recently developed single-shot line scan imaging technique for diffusion measurements (Finsterbusch and Frahm, Magn Reson Med 1999;42:772-778) was extended to full diffusion tensor mapping of the human brain. Because the sequence acquires stimulated echoes from individual columns of magnetization ("lines"), the approach is affected neither by spatial aliasing when studying inner volumes nor by resonance offset effects or T2* dephasing as in diffusion-weighted echoplanar imaging. Experiments on healthy subjects were performed at 2.0 T using 31 single-shot images (5b values, 6 orientations, 520 msec each) at 1.5 x 1.5 mm2resolution (interpolated) and 6.0 mm section thickness. Apart from calculated images with isotropic diffusion weighting, the results include maps of the six independent diffusion tensor components, the apparent diffusion coefficient, the relative anisotropy, and the main diffusion direction. The achievable signal-to-noise ratio and resolution allow the identification of differently oriented nerve fibers in the brain stem. J. Magn. Reson. Imaging 2000;12:388-394.