Signa 1.5 tesla lx mri system

Diffusion-weighted imaging data were acquired using a GE Signa 1.5 Tesla LX MRI system (General Electric, Milwaukee, WI, USA) with a standard birdcage quadrature head coil, using an echo planar imaging sequence peripherally gated to the cardiac cycle and optimized for the acquisition of white matter diffusion tensor MRI. Seven non-diffusion-weighted images (b = 0) were acquired, along with 64 images with diffusion gradients (b = 1300 s/mm2) uniformly distributed in space (Jones et al., 2002 (link)) at each of 60 slices. The TR was 15 cardiac R-R intervals with a TE of 107 ms. Whole-head acquisition gave isotropic (2.5 mm × 2.5 mm × 2.5 mm) voxels, reconstructed to a 1.875 × 1.875 mm in-plane pixel size. Following mutual-information image correction (diffusion images individually registered to the mean image see Catani et al., 2002 (link)), in-house software was used to remove non-brain tissue, determine the diffusion tensor using multivariate linear regression on log-transformed signal intensities, and calculate the FA in each remaining voxel (Basser et al., 1994 (link)).

Diffusion-weighted imaging data were acquired using a GE Signa 1.5 Tesla LX MRI system (General Electric, Milwaukee, Wisconsin, USA) with a standard birdcage quadrature head coil, using an echo planar imaging sequence peripherally gated to the cardiac cycle and optimised for the acquisition of white matter diffusion tensor MRI. Seven non-diffusion-weighted images (b = 0) were acquired, along with 64 images with diffusion gradients (b = 1300 s/mm2) uniformly distributed in space [23] (link) at each of 60 slices. The TR was 15 cardiac R-R intervals with a TE of 107 ms. Whole-head acquisition gave isotropic (2.5 mm³) voxels, reconstructed to a 1.875×1.875 mm in-plane pixel size. Following a mutual-information image correction (see [24] (link)), in-house software was used to remove non-brain tissue, determine the diffusion tensor and calculate the fractional anisotropy (FA) in each remaining voxel [25] (link).