Spatial encoding MR data of a moving subject using a higher-order gradient field
AssigneeGeneral Electric Company
InventorsRichard Scott Hinks, Kevin F. King, Jason A. Polzin
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Abstract
The present invention includes a technique for use with magnetic resonance imaging that includes the application of a non-linear, higher-order gradient field in the presence of a moving object to be scanned. MR data is acquired as the object moves through the non-linear gradient field. Resulting images are contiguous and do not require the patching together of data in either k-space or image space and result in an image with expanded FOV in a longitudinal direction of the moving object.
Claims28
A method of acquiring spatially encoded MR data comprising the steps of:
- applying a gradient field having an exponential relation higher than a single order along an object direction;
- moving an object to be scanned in the object direction through the gradient field;
- and
- acquiring MR data as the object moves with contiguous continuity in the object direction.
An MR pulse sequence comprising:
- a series of RF pulses, each RF pulse occurring within a defined repetition time period TR;
- and
- a phase encoding gradient comprised of a higher order gradient having a consistent value as applied in each TR.
An MR apparatus to acquire continuous imaging of a moving object over an extended FOV comprising:
- a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet to impress a polarizing magnetic field and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images, wherein at least one of the gradient coils is constructed to impart a higher-order gradient field;
- a table moveable along a longitudinal axis into and out of the bore of the magnet;
- and
- a computer programmed to:
- transmit a series of RF pulses;
- apply a higher-order gradient field between each RF pulse in the series of RF pulses;
- and
- move the table and acquire data.
A method of acquiring MR images with expanded FOV in a longitudinal direction of an object comprising the steps of:
- defining a direction of motion of an object to be scanned;
- arranging the object such that a longitudinal axis is positioned along the direction of motion;
- applying a non-linear gradient field in the direction of motion;
- moving the object through the applied non-linear gradient field;
- and
- acquiring k-space data with spatial encoding in the direction of motion.
A computer program comprising instructions which, when executed by a computer, cause the computer to:
- A)initiate transmission of an RF signal toward an imaging object;
- B)energize a higher-order gradient coil;
- C)acquire MR data;
- D)move the imaging object;
- E)repeat steps A-D until sufficient MR data is acquired along a desired length of the imaging object coincident with a direction of motion;
- and
- F)reconstruct a contiguous image of the desired length of the object.
A method of acquiring MR images with expanded FOV comprising the steps of:
- defining a default FOV based on characteristics of an MR scanner;
- defining a desired FOV larger than the default FOV;
- defining a motion axis to move an object through the MR scanner;
- applying a non-linear gradient field;
- moving the object along the motion axis and through the non-linear gradient field;
- and
- acquiring k-space data over the desired FOV to reconstruct a continuous image over the desired FOV.
Dependencies are inferred from the claim text.