| 摘要 |
A method for acquiring spatially and spectrally selective MR images by means of an MR imaging system includes the step of selecting an SPSP pulse sequence, comprising a succession of RF sub-pulses and an oscillatory gradient magnetic field, which is disposed to select a slice through a subject. The method further includes measuring specified parameters of a perturbation magnetic field associated with the imaging system, and deriving an expression for the perturbation field from respective measured parameters and from the oscillatory gradient magnetic field. A specified ideal frequency modulation function, associated with the SPSP sequence, is disposed to offset the slice to a particular spatially localized region of the subject. The SPSP pulse sequence is modified by adjusting the frequency modulation function in specified corresponding relationship with the expression. The modified SPSP pulse sequence is then applied to the subject to excite a selected spectral species in the spatially localized region, while substantially reducing signal intensity loss resulting from the perturbation magnetic field.
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