Patent ID: 7091720

Claim:
A method for avoiding peripheral interference signals when using a spin-echo pulse sequence for magnetic resonance tomography, comprising the steps of: placing a subject in a basic magnetic field having a homogenous volume adjoining a non-homogeneous volume; obtaining echo signals from the subject in said basic magnetic field using a spin-echo pulse sequence, including emitting a radio-frequency excitation pulse and, during said radio-frequency excitation pulse, activating a first slice selection gradient, and emitting a radio-frequency refocusing pulse and, during said radio-frequency refocusing pulse, activating a second slice selection gradient; and in said spin-echo sequence, employing a radio-frequency excitation pulse having an average frequency and a bandwidth that differ from an average frequency and a bandwidth of said radio-frequency refocusing pulse, and activating said first slice selection gradient with an amplitude g 1 differing from an amplitude g 2 of said second slice selection gradient g 2 =(1+ε)g 1 , for superimposing a transverse excitation slice in the subject produced by said radio-frequency excitation pulse in said homogenous volume, and a refocusing slice in the subject produced by said radio-frequency refocusing pulse in said homogenous volume, and locally separating, from said homogenous volume, a portion of said refocusing slice produced by said radio-frequency refocusing pulse in said non-homogenous volume for substantially preventing echo signals from arising in said non-homogenous volume, wherein ɛ > 1 ( R - r ) / d - 1 / 2 , wherein R is the radius of the homogenous volume, r is a slice position of said transverse layer, and d is a thickness of said transverse excitation slice.