Measurement and automatic correction of high-order B0 inhomogeneity in the rat brain at 11.7 Tesla.
In vivo B(0) inhomogeneity in the rat brain at 11.7 Tesla was measured and decomposed up to the fourth-order spherical harmonic terms using an automatic slice shimming routine derived from the FLATNESS method. In vivo shimming of horizontal slices showed that significant improvement in the T(2)*-weighted echo-planar imaging was achieved after correction of all first-, second- and third-order in-slice shims. For localized proton spectroscopy, reproducible, high quality data were obtained after correcting all first- and second-order shims. The measured high-order in vivo B(0) inhomogeneity in terms of spherical harmonic terms should provide a useful guide for designing shims to meet in vivo requirements.
Chen
Zhengguang
Z
Molecular Imaging Branch, NIMH, National Institute of Health, Bethesda, MD 20892, USA.
Li
Shizhe Steve
SS
Yang
Jehoon
J
Letizia
David
D
Shen
Jun
J
D000818:Animals; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D017352:Echo-Planar Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D023421:Models, Animal; D019047:Phantoms, Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley