×

Adaptive method for reducing motion and flow artifacts in NMR images

  • US 4,937,526 A
  • Filed: 06/13/1989
  • Issued: 06/26/1990
  • Est. Priority Date: 11/23/1988
  • Status: Expired due to Term
First Claim
Patent Images

1. An NMR system, the combination comprising:

  • means for generating a polarizing magnetic field;

    excitation means for generating an RF excitation magnetic field which produces transverse magnetization in nuclei subjected to the polarizing magnetic field;

    receiver means for sensing the NMR signal produced by the transverse magnetization and producing digitized in-phase (I) and quadrature (Q) samples of the NMR signal;

    first gradient means for generating a first magnetic field gradient to impart a first phase component into the NMR signal which is indicative of the location of the transversely magnetized nuclei along a first coordinate axis;

    second gradient means for generating a second magnetic field gradient to impart a second phase component into the NMR signal which is indicative of the location of the transversely magnetized nuclei along a second coordinate axis;

    pulse control means coupled to the excitation means, first and second gradient means, and receiver means, said pulse control means being operable to conduct a scan in which a series of pulse sequences are conducted in which the second magnetic field gradient is stepped through a series of discrete values and a corresponding series of NMR signals are sensed and digitized to form an NMR data set; and

    processor means for storing the NMR data set and for reconstructing an image array for a display from the stored NMR data set by;

    (a) Fourier transforming the NMR data set along one of its dimensions to create hybrid-space data arrays I'"'"' and Q'"'"';

    (b) producing a correction data array using the data in the hybrid-space data arrays I'"'"' and Q'"'"' by calculating the magnitude of the transformed sampled NMR signals in the hybrid-space data arrays I'"'"' and Q'"'"' to produce a modulus array, and correlating each row of the modulus array to produce a corresponding shift value for the correction data array;

    (c) applying the data in the correction data array to the NMR data set to reduce motion effects; and

    (d) Fourier transforming the corrected NMR image data set to produce the image array.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×