B1 and/or B0 mapping in MRI system using k-space spatial frequency domain filtering with complex pixel by pixel off-resonance phase in the B0 map
First Claim
Patent Images
1. A method for generating a B0 map in an MRI system, said method comprising using an MRI system to:
- (a) acquire at least one set of amplitude tagged MRI data signals in spatial frequency domain k-space from MR nuclei within an imaged volume of the MRI system;
(b) process said k-space data with at least one data processor in order to produce at least two sub-sets of frequency-filtered k-space data including at least two of;
(i) a baseline low-frequency sub-set,(ii) a positive higher frequency sub-set including a harmonic version of said baseline sub-set, and(iii) a negative higher frequency sub-set including a harmonic version of said baseline sub-set;
(c) separately Fourier transform each of said at least two sub-sets in order to produce at least two respectively corresponding complex-valued spatial domain data sets;
(d) arithmetically combine said at least two complex-valued spatial domain data sets on a pixel-by-pixel basis in order to generate and provide an off-resonance phase set of pixel data representing a B0 map value; and
(e) store said B0 map values in a non-transitory computer accessible and readable memory device that is subsequently usable by said MRI system.
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Abstract
Frequency filtering of spatially modulated or “tagged” MRI data in the spatial frequency k-space domain with subsequent 2DFT to the spatial domain and pixel-by-pixel arithmetic calculations provide robust data that can be used to derive B1 and/or B0 maps for an MRI system.
29 Citations
17 Claims
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1. A method for generating a B0 map in an MRI system, said method comprising using an MRI system to:
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(a) acquire at least one set of amplitude tagged MRI data signals in spatial frequency domain k-space from MR nuclei within an imaged volume of the MRI system; (b) process said k-space data with at least one data processor in order to produce at least two sub-sets of frequency-filtered k-space data including at least two of; (i) a baseline low-frequency sub-set, (ii) a positive higher frequency sub-set including a harmonic version of said baseline sub-set, and (iii) a negative higher frequency sub-set including a harmonic version of said baseline sub-set; (c) separately Fourier transform each of said at least two sub-sets in order to produce at least two respectively corresponding complex-valued spatial domain data sets; (d) arithmetically combine said at least two complex-valued spatial domain data sets on a pixel-by-pixel basis in order to generate and provide an off-resonance phase set of pixel data representing a B0 map value; and (e) store said B0 map values in a non-transitory computer accessible and readable memory device that is subsequently usable by said MRI system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An MRI system comprising:
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an MRI scanner configured to acquire at least one set of amplitude tagged MRI data signals in spatial frequency domain k-space from MR nuclei within an imaged volume of the MRI system; and at least one processor configured to; process said k-space data in order to produce at least two sub-sets of frequency-filtered k-space data including at least two of; (i) a baseline low-frequency sub-set, (ii) a positive higher frequency sub-set including a harmonic version of said baseline sub-set, and (iii) a negative higher frequency sub-set including a harmonic version of said baseline sub-set; separately Fourier transform each of said at least two sub-sets in order to produce at least two respectively corresponding complex-valued spatial domain data sets; arithmetically combine said at least two complex-valued spatial domain data sets on a pixel-by-pixel basis in order to generate and provide an off-resonance phase set of pixel data representing a B0 map value; and store said B0 map values in a non-transitory computer accessible and readable memory device for subsequent use by said MRI system. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification