Patent ID: 7038453
Filing Date: 2006-05-02
Classification: G01R

Abstract:
1. A method for spatially resolved measurement of a radio-frequency field distribution associated with radio-frequency pulses emitted by a radio-frequency antenna of magnetic resonance imaging apparatus adapted to receive an examination object therein, comprising the steps of: emitting a double echo radio-frequency pulse sequence including a first excitation pulse followed by at least two refocusing pulses, respectively for generating a first echo and a following second echo, at least the excitation pulse being slice selective for exciting nuclear spins, by giving said nuclear spins a flip angle, in a selected slice of the examination object, said first excitation pulse and said at least two refocusing pulses producing an electromagnetic field having a field strength; in the slice defined by said slice selective excitation pulse, spatially encoding a first echo image, associated with said first echo, and a second echo image, associated with said second echo by activating respective gradient pulses for at least one of phase encoding and frequency encoding, said first and second echo images respectively having amplitudes at a plurality of locations in the first and second echo images; and from a relationship of said amplitudes of said first and second echo images at said plurality of locations, determining said flip angle, as a representation of said field strength, in the slice selected by said excitation pulse.