Reduced-FOV Imaging with Excitation Using Nonlinear Gradient Magnetic Fields (ENiGMa)

Emre Kopanoglu¹, Ergin Atalar², Robert Todd Constable³

A reduced-FOV imaging method that employs nonlinear gradient fields for excitation is demonstrated using an additional gradient amplifier, a transmit array architecture and a head-sized nonlinear gradient coil. The method makes use of the non-Cartesian shape of the excitation profile to channel folding artifacts to outer sections of the image. Although scan time reduction is application specific, for a given example, around 60% reduction is shown. The main advantage of the proposed method is that the echo and repetition times, as well as the SAR are kept unaltered, compared to a conventional excitation approach.