Method and magnetic resonance system to acquire MR data in a predefined three-dimensional volume segment

摘要

In a method and magnetic resonance (MR) apparatus to acquire MR data in a predetermined three-dimensional volume segment of an examination subject, the three-dimensional volume segment is selectively excited with an RF excitation pulse, wherein a magnetic field gradient at the same time is switched. Two phase coding gradients and an additional magnetic field gradient are switched for spatial coding and MR data are acquired depending on this. A frequency range of the RF excitation pulse is set depending on resonance frequencies of at least two substances to be acquired within the volume segment, such that a center frequency of the frequency range is caused to be located between the resonance frequencies.

主权项

1. A method to acquire magnetic resonance (MR) data comprising:
from a computerized control unit, operating an MR data acquisition unit with an examination subject therein to acquire MR data from a predetermined three-dimensional volume segment of the examination subject by selectively exciting nuclear spins in said three-dimensional volume segment with a radio frequency (RF) excitation pulse while simultaneously activating a first magnetic field gradient, two second magnetic field gradients, and a third magnetic field gradient; acquiring said MR data from the three-dimensional volume segment of the examination subject, resulting from the excited nuclear spins, with phase coding by said two second magnetic field gradients and spatial coding by said third magnetic field gradient; and in said computerized control unit, setting a frequency range of said RF excitation pulse dependent on respective resonant frequencies of at least two types of said nuclear spins in said three-dimensional volume segment, to cause a center frequency of said frequency range to be between said respective resonance frequencies by calculating an average of said resonance frequencies of said at least two types of nuclear spins, and setting said center frequency to be equal to said average.