METHOD AND MAGNETIC RESONANCE APPARATUS FOR CORRECTING FIELD DRIFTS OF A HIGHER ORDER THAT OCCUR DUE TO THE OPERATION OF GRADIENT COILS

摘要

In a method and magnetic resonance apparatus for correcting field drifts of a higher order than the zeroth order that occur due to the operation of gradient coils in a magnetic resonance scanner while recording magnetic resonance data, at least one temperature sensor is used to determine the gradient coil temperature directly on the gradient coils, and as a function of the gradient coil temperature, at least one field variable describing at least one part of the field drifts is determined, and the field drifts are corrected by the actuation of the gradient coils and/or shim coils being modified in order to compensate for field drifts described by the field variable, and/or the acquired magnetic resonance data are corrected in post-processing as to the effects of the field drifts described by the field variable.

主权项

1. A method for correcting field drifts of a higher order than the zeroth order that occur in a basic magnetic field in a magnetic resonance scanner due to operation of gradient coils in the scanner while acquiring magnetic resonance data with the scanner, said method comprising:
operating a magnetic resonance scanner to acquire magnetic resonance data from a subject therein, including generating a basic magnetic field in the scanner, generating gradient magnetic fields with gradient coils in the scanner being operated with gradient coils operating parameters, and shimming the basic magnetic field with shim coils operated with shim coils data acquisition parameters; with a temperature sensor, sensing a gradient coil temperature directly on the gradient coils, and emitting a temperature sensor signal representing said temperature; providing said temperature sensor signal to a computer and, in said computer, executing a field drift determining algorithm to determine a field variable that describes at least a portion of field drifts that occur in said basic magnetic field due to said temperature; and correcting said field drifts by executing at least one correction algorithm in said computer selected from the group consisting of a gradient coils parameter modification algorithm that modifies said gradient coils data acquisition parameters dependent on said field variable and that results said computer emitting electrical signals to said gradient coils representing modified gradient coils operating parameters, a shim coils parameter modification algorithm that modifies said shim coils data acquisition parameters dependent on said field variable and that results in said computer emitting electrical signals to said shim coils that represent modified shim coils operating parameters, and a post-processing algorithm that corrects, dependent on said field variable, effects of field drifts in said magnetic resonance data acquired from the subject and that results in said computer emitting post-processed magnetic resonance data in electronic form as a data file.