Imaging of water and fat fractions in high-field MRI with multiple slice chemical shift-selective inversion recovery

Fat and water fractions were quantified at high field using. chemical shift -selective inversion recovery (CSS-IR) sequence to address the major diffic ulties encountered at gh field by phase-sensitive techniques used for fat/w ater discrimination. Water- and fat-suppressed Images were perfectly regist ered, which is a prerequisite for quantification. Immunity of the Inversion pulse to B-1 field modulations and off-resonance effects was tested for tw o adiabatic inversion pulses, with hyperbolic secant and asymmetric hyper-p ulse waveforms. Taking Into account adiabaticity, immunity to off-resonance , radiofrequency power requirements, and specific absorption rate, the form er was chosen. A close correlation was found between fat content measured b y CSS-IR at 4.7 T (R-2 = 0.97, P < 0.001) and 9.4 T (R-2 = 0.99, P < 0.05) and that measured by Soxhlet extraction. Different sources of bias (low sig nal-to-noise ratio, magnetization transfer effect) are discussed. <(c)> 200 0 Wiley-Liss, Inc.