Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5407092 | Journal of Magnetic Resonance | 2008 | 9 Pages |
Abstract
At high magnetic field, B1+ non-uniformity causes undesired inhomogeneity in SNR and image contrast. Parallel RF transmission using tailored 3D k-space trajectory design has been shown to correct for this problem and produce highly uniform in-plane magnetization with good slice selection profile within a relatively short excitation duration. However, at large flip angles the excitation k-space based design method fails. Consequently, several large-flip-angle parallel transmission designs have recently been suggested. In this work, we propose and demonstrate a large-flip-angle parallel excitation design for 90° and 180° spin-echo slice-selective excitations that mitigate severe B1+ inhomogeneity. The method was validated on an 8-channel transmit array at 7 T using a water phantom with B1+ inhomogeneity similar to that seen in human brain in vivo. Slice-selective excitations with parallel RF systems offer means to implement conventional high-flip excitation sequences without a severe pulse-duration penalty, even at very high B0 field strengths where large B1+ inhomogeneity is present.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Kawin Setsompop, Vijayanand Alagappan, Adam C. Zelinski, Andreas Potthast, Ulrich Fontius, Franz Hebrank, Franz Schmitt, Lawrence L. Wald, Elfar Adalsteinsson,