Diffusion-weighted radial fast spin-echo for high-resolution diffusion tensor imaging at 3T

✍ Scribed by Joelle E. Sarlls; Carlo Pierpaoli

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 477 KB
• Volume: 60
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.21639

✦ Synopsis

Abstract

There is a need for an imaging sequence that can provide high‐resolution diffusion tensor images at 3T near air–tissue interfaces. By employing a radial fast spin‐echo (FSE) collection in conjunction with magnitude filtered back‐projection reconstruction, high‐resolution diffusion‐weighted images can be produced without susceptibility artifacts. However, violation of the Carr‐Purcell‐Meiboom‐Gill (CPMG) condition of diffusion prepared magnetization is a prominent problem for FSE trains that is magnified at higher fields. The unique aspect of violating the CPMG condition in trajectories that oversample the center of k‐space and the implications for choosing the solution are examined. For collecting diffusion‐weighted radial‐FSE data at 3T we propose mixed‐CPMG phase cycling of RF refocusing pulses combined with a 300% wider refocusing than excitation slice. It is shown that this approach produces accurate diffusion values in a phantom, and can be used to collect undistorted, high‐resolution diffusion tensor images of the human brain. Magn Reson Med 60:270–276, 2008. © 2008 Wiley‐Liss, Inc.