In this work we compare a single flip angle and dual flip angle approach to overcome B1 inhomogeneities in DW-SSFP data of post mortem human brain at 7T. Both approaches were designed and optimized to achieve optimal CNR with whole brain coverage. The single flip angle approach displayed slight improvements in orientation estimates; however, the dual flip angle approach is being further investigated as a potential source of microstructural estimates with little to no cost in orientation.Abstract and Poster - International Society for Magnetic Resonance in Medicine (ISMRM) 24th Annual Meeting & Exhibition, Session - Diffusion, May 07th - 13th, 2016.
In this work we present voxel-wise orientation estimates from diffusion-weighted steady state free precession MRI data of post-mortem human brain, acquired with three resolutions at 7T. Data were acquired with 0.5mm, 1mm, and 2mm isotropic resolution over 90 directions. These resolutions were chosen because 1mm and 2mm are typical of in vivo DTI. Deterministic tractography was produced in various regions using the highest resolution dataset. Orientation maps demonstrate small structures that are less apparent in lower resolution data. Orientation estimates and tractography results were validated with polarized light microscopy imaging. Abstract and Presentation Video - International Society for Magnetic Resonance in Medicine (ISMRM) 24th Annual Meeting & Exhibition, Session - Diffusion Validation Using Phantoms & Histology, May 07th - 13th, 2016.