Multi-Shot, Diffusion-Weighted Imaging at 3T using Readout-Segmented EPI and GRAPPA
Heidemann R, Porter D
Siemens Medical Solutions
The increased signal-to-noise at 3T is a particular benefit in diffusion-weighted imaging due to the inherently low signal levels. However, routine diffusion-weighted image quality is degraded by the sensitivity of single-shot EPI to the increased susceptibility and T2* decay effects at 3T. A number of options exist for improvement using multi-shot methods. This study investigated the readout-segmented EPI technique, using a GRAPPA reconstruction to give a reduction in EPI echo-train length. The method was found to give a substantial reduction in susceptibility artefact, allowing high-resolution T2- and trace-weighted images to be acquired with typical scan times of around 3 minutes.