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US 7,888,935 B1Granted
K-space trajectory estimation in spiral MRI system and related method thereof
AssigneeUniversity of Virginia Patent Foundation
InventorsHao Tan, Craig H. Meyer
Life of this patent
Estimating the term…
Abstract
First, benchmark data are collected on two thin slices of an object to get measured k-space trajectories. To find delays on different physical gradients, the root mean square error between estimated and measured k-space trajectories is minimized for different delays. To reduce the error further, an eddy current compensation is introduced along each physical gradient axis. A more accurate estimation of the k-space trajectory can be obtained to image the object.
Claims12
A method for imaging an object, the method comprising:
- (a) scanning at least two slices of a calibration object;
- (b) measuring k-space trajectories in said at least two slices to obtain benchmark data;
- (c) scanning the object to obtain image data for a plurality of gradient axes;
- (d) applying an anisotropic delay to the image data for each of the gradient axes, wherein the anisotropic delay is determined so as to minimize an error between the image data and the benchmark data;
- (e) obtaining a first k-space trajectory estimate from the image data to which the anisotropic delay has been applied;
- (f) applying an eddy current compensation to the image data for each of the gradient axes, the eddy current compensation being determined in accordance with a difference between the measured k-space trajectories and the first k-space trajectory estimate;
- (g) obtaining a second k-space trajectory estimate from the image data with the anisotropic delay and the eddy current compensation applied;
- and
- (h) reconstructing an image of the object using the second k-space trajectory estimate.
6 more elements
A system for imaging an object, the system comprising:
- a scanner for scanning the object;
- a processor, in communication with the scanner, for scanning at least two slices of a calibration object, measuring k-space trajectories in said at least two slices to obtain benchmark data, scanning the object to obtain image data for a plurality of gradient axes, applying an anisotropic delay to the image data for each of the gradient axes, wherein the anisotropic delay is determined so as to minimize an error between the image data and the benchmark data, obtaining a first k-space trajectory estimate from the image data to which the anisotropic delay has been applied, applying an eddy current compensation to the image data for each of the gradient axes, the eddy current compensation being determined in accordance with a difference between the measured k-space trajectories and the first k-space trajectory estimate, obtaining a second k-space trajectory estimate from the image data with the anisotropic delay and the eddy current compensation applied, and reconstructing an image of the object using the second k-space trajectory estimate;
- and
- an output, in communication with the processor, for outputting the image.
1 more element
A method for imaging an object with a scanner, the method comprising:
- (a) retrieving benchmark data and calibration data for the scanner, the benchmark data and the calibration data representing k-space trajectories of a calibration object measured in the scanner;
- (b) scanning the object to obtain image data for a plurality of gradient axes;
- (c) applying an anisotropic delay to the image data for each of the gradient axes, wherein the anisotropic delay is determined so as to minimize an error between the image data and the benchmark data;
- (d) obtaining a first k-space trajectory estimate from the image data to which the anisotropic delay has been applied;
- (e) applying an eddy current compensation to the image data for each of the gradient axes, the eddy current compensation being determined in accordance with a difference between the measured k-space trajectories and the first k-space trajectory estimate;
- (f) obtaining a second k-space trajectory estimate from the image data with the anisotropic delay and the eddy current compensation applied;
- and
- (g) reconstructing an image of the object using the second k-space trajectory estimate.
5 more elements
Dependencies are inferred from the claim text.