PUSHUP-CEST: Calibration free homogeneous saturation for ulta-high field CEST imaging

CEST imaging benefits from the increased spectral resolution at ultra-high field. Due to the inhomogeneous RF field, a B1+-correction is necessary, which requires repeated measurements. The number of required repetitions can be reduced to two by using a ptx-based saturation scheme, like MIMOSA. We present an alternative saturation scheme that is based on PUSH saturation and universal pulses, which we name PUSHUP. Using this approach, we could reduce the inhomogeneity of the CEST saturation as effectively as MIMOSA while being more SAR efficient.