MR imaging method with motion compensation
AssigneeKoninklijke Philips Electronics N.V.
InventorsKay Nehrke, Peter Boernert, Bernd Aldefeld, Michael Harald Kuhn, Dirk Manke
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Abstract
An MR imaging method wherein motion of an object to be imaged is examined during a preparation phase preceding the actual MR examination. The necessary sequences for the subsequent MR examination are modified during the examination to compensate for the motion based on motion parameters calculated during the preparation phase or motion parameters derived from the motion parameters calculated during the preparation phase based on a correlation between the motion parameters.
Claims20
A method for MR imaging of a moving object in an examination zone, comprising:
- correlating a plurality of motion parameters,
- measuring a variation in time of the correlated motion parameters during a preparation phase preceding an examination phase,
- measuring only a portion of the correlated motion parameters during the examination phase,
- deriving a remaining portion of the motion parameters which were not measured from the measured portion of the correlated motion parameters,
- exciting the nuclear magnetization in the presence of a steady magnetic field by sequences which include at least a respective RF pulse of defined frequency,
- evaluating MR signals received with a defined phase position and produced under the influence of additional magnetic gradient fields, and
- varying at least one parameter of the sequence based on at least one of the derived or measured motion parameters in order to achieve motion compensation.
An apparatus for MR imaging of a moving object, comprising:
- a magnet for generating a uniform, steady magnetic field,
- an RF transmitter for generating magnetic RF pulses,
- a receiver for receiving MR signals,
- a generator for generating gradient magnetic fields with gradients that vary differently in time and space,
- an evaluation unit for processing the received MR signals, and
- a control unit arranged to control the RF transmitter, the receiver, the generator and the evaluation unit, the control unit being programmed to measure a variation in time of a plurality of correlated motion parameters during a preparation phase preceding an examination phase, measure only a portion of the correlated motion parameters during the examination phase, derive a remaining portion of the motion parameters which are not measured during the examination phase from the measured motion parameters and vary at least one parameter of a sequential generation of the magnetic field during the examination phase based on at least one of the derived or measured motion parameters in order to achieve motion compensation.
A device for generating a computer program for a control unit for controlling an MR imaging apparatus, comprising:
- means for measuring the variation in time of a plurality of correlated motion parameters during a preparation phase preceding an examination phase,
- means for measuring only a portion of the correlated motion parameters during the examination phase,
- means for deriving the motion parameters which are not measured during the examination phase from the measured motion parameters, and
- means for varying at least one parameter of a sequential generation of a magnetic field during the examination phase based on at least one of the derived or measured motion parameters in order to achieve motion compensation.
Dependencies are inferred from the claim text.