Method for correcting motion-induced phase errors in magnetic resonance imaging
First Claim
1. A method for correcting motion-induced phase errors in diffusion-weighted k-space data acquired with a magnetic resonance imaging (MRI) system, the steps of the method comprising:
- a) directing the MRI system to;
i) acquire three-dimensional diffusion-weighted k-space data from an imaging volume;
ii) acquire three-dimensional diffusion-weighted navigator data from the imaging volume;
iii) acquire three-dimensional non-diffusion-weighted k-space data from the imaging volume;
iv) acquire three-dimensional non-diffusion-weighted navigator data from the imaging volume;
b) calculating k-space shift values and a constant phase offset value using the three-dimensional diffusion-weighted navigator data acquired in step a)ii) and the three-dimensional non-diffusion-weighted navigator data acquired in step a)iv);
c) updating the k-space shift values and the constant phase offset value calculated in step b) by iteratively minimizing a cost function that relates a phase of the diffusion-weighted k-space data acquired in step a)i) to a phase of the non-diffusion-weighted k-space data acquired in step a)iii) as shifted by the k-space shift values and constant phase offset value calculated in step b); and
d) correcting the diffusion-weighted k-space data acquired in step a)i) for motion-induced phase errors using the k-space shift values and constant phase offset value updated in step c).
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Abstract
A method for correcting motion-induced phase errors in diffusion-weighted k-space data acquired with a magnetic resonance imaging (MRI) system is provided. The MRI system is directed to acquire the following data from an imaging volume: three-dimensional diffusion-weighted k-space data, three-dimensional diffusion-weighted navigator data, three-dimensional non-diffusion-weighted k-space data, and three-dimensional non-diffusion-weighted navigator data. Initial estimates of k-space shift values and a constant phase offset value are calculated using the three-dimensional diffusion-weighted navigator data and the three-dimensional non-diffusion-weighted navigator data. These initial k-space shift values and constant phase offset value are then updated by iteratively minimizing a cost function that relates the phase of the diffusion-weighted k-space data to the phase of the non-diffusion-weighted k-space data, as shifted by the initial k-space shift values and constant phase offset value. The diffusion-weighted k-space data is then corrected for motion-induced phase errors using the updated k-space shift values and constant phase offset value.
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Citations
7 Claims
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1. A method for correcting motion-induced phase errors in diffusion-weighted k-space data acquired with a magnetic resonance imaging (MRI) system, the steps of the method comprising:
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a) directing the MRI system to; i) acquire three-dimensional diffusion-weighted k-space data from an imaging volume; ii) acquire three-dimensional diffusion-weighted navigator data from the imaging volume; iii) acquire three-dimensional non-diffusion-weighted k-space data from the imaging volume; iv) acquire three-dimensional non-diffusion-weighted navigator data from the imaging volume; b) calculating k-space shift values and a constant phase offset value using the three-dimensional diffusion-weighted navigator data acquired in step a)ii) and the three-dimensional non-diffusion-weighted navigator data acquired in step a)iv); c) updating the k-space shift values and the constant phase offset value calculated in step b) by iteratively minimizing a cost function that relates a phase of the diffusion-weighted k-space data acquired in step a)i) to a phase of the non-diffusion-weighted k-space data acquired in step a)iii) as shifted by the k-space shift values and constant phase offset value calculated in step b); and d) correcting the diffusion-weighted k-space data acquired in step a)i) for motion-induced phase errors using the k-space shift values and constant phase offset value updated in step c). - View Dependent Claims (2, 3, 4, 5, 6, 7)
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