Simultaneous water and lipid suppression for in vivo brain spectroscopy in humans

A method to achieve simultaneous water and lipid suppression is described. The key feature of the new dual suppression technique is the use of the well-known hyperbolic secant (HS) waveform as a 90° saturation pulse. Two HS pulses with opposite frequency offsets are employed either sequentially or simultaneously to saturate resonance frequencies corresponding to water and lipid, while leaving the target spins untouched. The excitation bandwidth is controlled by the frequency sweep and offset of each pulse, while varying the pulse length controls the transition bandwidth. An example of the use of the dual saturation method in in vivo magnetic resonance spectroscopic imaging of the human brain is presented.