MGH DTI Protocol

DTI data will be acquired on a 3T Siemens Trio at MGH (Charlestown, MA) using a single-shot SENSE EPI sequence, and a Siemens 8-channel head coil. Sixty four axial oblique slices (AC-PC plane) will be acquired, providing whole-head coverage. The diffusion preparation will employ a twice-refocused balanced echo sequence. The imaging parameters will be TR/TE=8400/74ms, b=700s/mm2, 72 diffusion directions, 10 T2 images, 2x2 mm in-plane resolution, 2mm (skip 0) slice thickness, 5/8 partial Fourier, 3-fold SENSE acceleration. The n=72 diffusion gradient directions will be obtained using the electrostatic shell repulsion method (Jones 1999). The total acquisition time will be ~11 min 30 sec.