Reduction of susceptibility artifacts in subencoded single-shot magnetic resonance imaging

• US 7,298,143 B2
• Filed: 05/08/2003
• Issued: 11/20/2007
• Est. Priority Date: 05/13/2002
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Boesiger, Peter, Pruessmann, Klaas Paul, Schmidt, Conny Frauke, Weiger, Markus, Jaermann, Thomas
• Primary Examiner(s): Casler; Brian L.
• Assistant Examiner(s): Ramirez; John F.
• Application Number:
  US10/514,355
• Publication Number:
  US 20050212517A1
• Time in Patent Office: 1,657 Days
• Field of Search: 600407-423, 324306-309, 324318-322
• US Class Current: 324/307
• 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

In a magnetic resonance imaging method an echo train is generated of successive magnetic resonance signals from an object to be examined. The magnetic resonance signals are received with a degree of undersampling and by means of a receiver antennae system having a spatial sensitivity profile and the degree of undersampling is set on the basis of an amount of phase evolution due to a magnetic susceptibility distribution of the object to be examined.

Claims

1. A magnetic resonance imaging method comprising:

applying a static main magnetic field with a main field strength;

applying an acquisition sequence with an RF-excitation which generates an echo train of successive magnetic resonance signals from an object to be examined, the acquisition sequence including a diffusion sensitization subsequence;

receiving the magnetic resonance signals with a degree of undersampling by means of a receiver antennae system having a spatial sensitivity profile, the degree of undersampling is set on the basis of an amount of phase evolution due to a magnetic susceptibility distribution of the object to be examined;

reconstructing a magnetic resonance image from the magnetic resonance signals and the spatial sensitivity profile;

repeatedly applying the excitation sequence, receiving the magnetic resonance signals and reconstructing the magnetic resonance image to produce a series of magnetic resonance images;

matching said magnetic resonance images and determining mutual matches between said magnetic resonance images;

selecting a number of the magnetic resonance images from the series on the basis of the mutual matches;

averaging over said selected number magnetic resonance images.

2. A magnetic resonance imaging method as claimed in claim 1, wherein the degree of undersampling is dependent on the main field strength.

3. A computer processor or media programmed to perform the steps of:

repeatedly applying an excitation sequence, receiving resultant magnetic resonance signals, and reconstructing the magnetic resonance signals to produce a series of magnetic resonance images;

comparing the magnetic resonance images of the series to determine images with at least a preselected degree of similarity;

combining the magnetic resonance images of the series which have at least the preselected degree of similarity.

4. A magnetic resonance imaging system including a main magnet which applies a static magnetic field, an RF coil, a transmitter for applying an acquisition sequence with an RF excitation which generates an echo train of successive magnetic resonance signals from an object to be examined, a receiver antenna system having a spatial sensitivity profile, a receiver for receiving magnetic resonance signals from the receiver antenna system, and the computer processor media as claimed in claim 3.

5. A magnetic resonance imaging system including a main magnet which applies a static magnetic field, an RF coil, a transmitter for applying an acquisition sequence with an RF excitation which generates an echo train of successive magnetic resonance signals from an object to be examined, a receiver antenna system having a spatial sensitivity profile, a receiver for receiving magnetic resonance signals with a degree of undersampling from the receiver antenna system, and a controller, the controller being programmed to:

selectively adjust the degree of undersampling in accordance with an amount of phase evolution artifacting attributable to a magnetic susceptibility distribution of the object to be examined.

6. The apparatus as claimed in claim 5 further including a reconstruction processor programmed to:

repeatedly apply the excitation sequence, receive the magnetic resonance signals, and reconstruct the magnetic resonance signals to produce a series of magnetic resonance images;

compare the magnetic resonance images of the series to determine images with at least a preselected degree of similarity;

combine the magnetic resonance images of the series which have at least the preselected degree of similarity.