Method and apparatus for reduction of specific absorption rate (SAR) in magnetic resonance data acquisition

摘要

In the acquisition of magnetic resonance data from an examination subject according to a pulse sequence that causes radiation into the examination subject of a radiated radio frequency (RF) pulse having a frequency spectrum and a slice profile with a relationship therebetween, the examination subject is substantially simultaneously, with the radiated RF pulse, to a non-linear magnetic field that alters the relationship in the radiated RF pulse between the frequency spectrum and the slice profile. The alteration of this relationship can be used, for example, to reduce the specific absorption rate (SAR) of the examination subject during the acquisition of the magnetic resonance data.

主权项

1. A method for acquiring magnetic resonance (MR) data from an examination subject, comprising:
placing an examination subject in an MR data acquisition unit; operating the MR data acquisition unit with a pulse sequence protocol configured to acquire MR data from a slice of an examination subject within a volume of the MR data acquisition unit defined by spatial coordinates, said pulse sequence protocol comprising at least one defined radio-frequency (RF) pulse that causes radiation into said slice of a radiated RF pulse, said defined RF excitation pulse having a frequency spectrum and a slice profile with a relationship between said frequency spectrum and said slice profile; and substantially simultaneously with radiation of said radiated RF pulse, exposing said examination subject in said MR data acquisition unit to at least one non-linear magnetic field that is non-linear with respect to said spatial coordinates and, with said at least one non-linear magnetic field, altering said relationship in said radiated RF pulse between said frequency spectrum and said slice profile with respect to said relationship in said defined RF pulse.