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Three-dimensional phase contrast imaging using interleaved projection data

  • US 6,954,067 B2
  • Filed: 11/08/2002
  • Issued: 10/11/2005
  • Est. Priority Date: 11/12/2001
  • Status: Expired due to Term
First Claim
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1. A method for producing a magnetic resonance image indicative of spin motion, the steps comprising:

  • a) acquiring an NMR signal with an MRI system using a three-dimensional projection reconstruction pulse sequence which includes;

    producing an RF excitation field;

    producing a motion encoding gradient field GM directed along a motion encoding axis; and

    acquiring an NMR signal while producing a readout gradient to sample a three-dimensional k-space volume along a trajectory that extends substantially radially from the center of k-space;

    b) producing a first k-space data set by repeating step a) using different readout gradients to sample k-space throughout the three-dimensional k-space volume along different trajectories with substantially uniform spacing between trajectories;

    c) producing a second k-space data set by repeating steps a), and b) using a different motion encoding gradient GM;

    d) reconstructing a first phase image from the first k-space data set;

    e) reconstructing a second phase image from the second k-space data set;

    f) producing a velocity image by combining the first and second phase images, in which the initial motion encoding gradient field GM has a first moment +M1 and the second motion encoding gradient field GM has an opposite first moment −

    M1 and step f) is performed by subtracting the first and second phase images; and

    which includes repeating steps a)-c) a plurality of times using motion encoding gradient fields GM having different valued first moments +M1 and −

    M1 for each repeat, producing a corresponding plurality of first k-space data sets and a corresponding plurality of second k-space data sets, and wherein step f) includes subtracting corresponding k-space data sets in said plurality of first and second k-space data sets to form a plurality of subtracted k-space data sets, and performing a one-dimensional Fourier transformation along corresponding locations in the plurality of subtracted k-space data sets to produce velocity bin data sets.

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