Saturated double-angle method for rapid B1+ mapping

✍ Scribed by Charles H. Cunningham; John M. Pauly; Krishna S. Nayak

• Book ID: 102952810
• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 596 KB
• Volume: 55
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20896

✦ Synopsis

Abstract

For in vivo magnetic resonance imaging at high field (≥3 T) it is essential to consider the homogeneity of the active B~1~ field (B~1~+), particularly if surface coils are used for RF transmission. A new method is presented for highly rapid B~1~+ magnitude mapping. It combines the double angle method with a B~1~‐insensitive magnetization‐reset sequence such that the choice of repetition time (TR) is independent of T~1~ and with a multislice segmented (spiral) acquisition to achieve volumetric coverage with adequate spatial resolution in a few seconds. Phantom experiments confirmed the accuracy of this technique even when TR ≪ T~1~, with the side effect being lowered SNR. The speed of this method enabled B~1~+ mapping in the chest and abdomen within a single breath‐hold. In human cardiac imaging, the method enabled whole‐heart coverage within a single 16‐s breath‐hold. Results from phantoms and healthy volunteers at 1.5 T and 3 T are presented. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.