Magnetic resonance imaging method with sub-sampling

• US 6,377,045 B1
• Filed: 05/17/2000
• Issued: 04/23/2002
• Est. Priority Date: 05/20/1999
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Dydak, Ulrike, Lamerichs, Rudolf Mathias Johannes Nicolaas, Van Den Brink, Johan Samuel, Pruessmann, Klaas Paul, Van Muiswinkel, Arianne Margarethe Corinne, Weiger, Markus, Folkers, Paulus Johannes Maria
• Primary Examiner(s): ARANA, LOUIS M
• Application Number:
  US09/572,994
• Time in Patent Office: 706 Days
• Field of Search: 324/309, 324/307, 324/306, 324/300, 324/314, 324/312, 324/318, 324/322, 600/410, 600/421, 600/422
• US Class Current: 324/307
• CPC Class Codes: G01R 33/4822 in three dimensions
• CPC Class Codes: G01R 33/485 based on chemical shift information [CSI] or spectroscopic imaging, e.g. to acquire the spatial distributions of metabolites
• CPC Class Codes: G01R 33/5611 Parallel magnetic resonance imaging, e.g. sensitivity encoding [SENSE], simultaneous acquisition of spatial harmonics [SMASH], unaliasing by Fourier encoding of the overlaps using the temporal dimension [UNFOLD], k-t-broad-use linear acquisition speed-up technique [k-t-BLAST], k-t-SENSE structural details of arrays of sub-coils G01R33/3415

Abstract

A spectroscopic magnetic resonance imaging method involves sub-sampling in the k space. For example, the SENSE technique is applied in spectroscopic MR imaging. Such sub-sampling is also applied in three-dimensional MR imaging.

Claims

1. A spectroscopic magnetic resonance imaging method comprising the steps of:

generating an RF excitation pulse in an examination space,

generating magnetic resonance signals in an object to be examined in the examination space in response to said RF excitation pulse, the magnetic resonance signals being received in a sub-sampled fashion by a set of receiving coils having a coil sensitivity profile,

wherein a plurality of positions in a measuring plane in the examination space in which the magnetic resonance signals are generated are encoded on the basis of at least two linearly independent components of the wave vector of the magnetic resonance signals,

wherein a frequency distribution of the magnetic resonance signals represents spectroscopic information concerning the object to be examined, and

wherein a spectroscopic magnetic resonance image is reconstructed from the sub-sampled magnetic resonance signals and the coil sensitivity profile.

2. The spectroscopic magnetic resonance imaging method as claimed in claim 1, further including applying phase encoding gradients in one of:

two and three linearly independent directions, subsequent to the generation of the RF excitation pulse and prior to the reception of the magnetic resonance signals by the receiving coils.

3. The spectroscopic magnetic resonance imaging method as claimed in claim 1, further including

reconstructing spectroscopic receiving coil images from the sub-sampled magnetic resonance signals received by individual receiving coils, and

deriving the spectroscopic magnetic resonance image from such spectroscopic receiving coil images and the coil sensitivity profile.

4. A magnetic resonance imaging method comprising the steps of:

generating an RF excitation pulse in an examination space, and

generating magnetic resonance signals in an object to be examined in the examination space in response to said RF excitation pulse,

wherein the magnetic resonance signals are received in a sub-sampled fashion by a set of receiving coils having a spatial coil sensitivity profile,

wherein the positions in the examination space in which the magnetic resonance signals are generated are encoded in three dimensions on the basis of gradient fields in three linearly independent directions, and

wherein a three-dimensional density distribution of the object is reconstructed from the sub-sampled magnetic resonance signals and the coil sensitivity profile.

5. The magnetic resonance imaging method as claimed in claim 4, further comprising

applying phase encoding gradients in two linearly independent directions, subsequent to the generation of the RF excitation pulse and prior to the reception of the magnetic resonance signals by the receiving coils, and

perpendicularly applying a read-out gradient to the directions of the phase encoding gradients during the reception of the magnetic resonance signals.

6. The magnetic resonance imaging method as claimed in claim 4, wherein

three-dimensional receiving coil density distributions are reconstructed from the sub-sampled magnetic resonance signals received by individual receiving coils, and

the three-dimensional density distribution of the object is reconstructed from the receiving coil densities and the coil sensitivity profile.

7. A magnetic resonance imaging method (MRI method), comprising the steps of:

administering a contrast agent to the patient to be examined,

generating an RF excitation pulse in an examination space,

generating magnetic resonance signals in the patient to be examined in response to said RF excitation pulse, and

receiving magnetic resonance signals generated by the RF excitation pulse in the part of the patient to be examined in which the administered contrast agent is present utilizing a set of at least one receiving coil,

wherein the positions in the examination space in which the magnetic resonance signals are generated are encoded in three dimensions on the basis of gradient fields in three linearly independent directions, and

wherein a three-dimensional density distribution of a part of the object filled with contrast agent is reconstructed from the sub-sampled magnetic resonance signals and the coil sensitivity profile.

8. A magnetic resonance imaging system, comprising:

first generating means arranged to generate an RF excitation pulse in an examination space, and

second generating means arranged to generate, due to the RF excitation pulse, magnetic resonance signals in an object to be examined in the examination space,

wherein the magnetic resonance signals are received in a sub-sampled fashion by a set of receiving coils having a coil sensitivity profile,

wherein the positions in a measuring plane in the examination space in which the magnetic resonance signals are generated are encoded on the basis of at least two linearly independent components of the wave vector of the magnetic resonance signals,

wherein a frequency distribution of the magnetic resonance signals represents spectroscopic information concerning the object to be examined, and

wherein a spectroscopic magnetic resonance image is reconstructed from the sub-sampled magnetic resonance signals and the coil sensitivity profile.

9. A magnetic resonance imaging system constructed to include:

first means to generate an RF excitation pulse in an examination space,

second means to generate, due to the RF excitation pulse, magnetic resonance signals in an object to be examined in the examination space, and

means to receive the magnetic resonance signals in a sub-sampled fashion by way of a set of receiving coils having a spatial coil sensitivity profile,

wherein the positions in the examination space in which the magnetic resonance signals are generated are encoded in three dimensions on the basis of gradient fields in three linearly independent directions, and

wherein a three-dimensional density distribution of the object is reconstructed from the sub-sampled magnetic resonance signals and the coil sensitivity profile.

10. A computer program with instructions to:

receive a plurality of magnetic resonance signals in a sub-sampled fashion by way of a set of receiving coils having a coil sensitivity profile,

encode positions in a measuring plane in the examination space in which the magnetic resonance signals are generated on the basis of at least two linearly independent components of the wave vector of the magnetic resonance signals,

representing a frequency distribution of the magnetic resonance signals as spectroscopic information concerning the object to be examined, and

reconstructing a spectroscopic magnetic resonance image from the sub-sampled magnetic resonance signals and the coil sensitivity profile.