Generic Magnetic Resonance Imaging Gradient Delay Correction Method for Radial and Spiral Acquisitions


Vanderbilt researchers have developed a way to correct for ubiquitous gradient delay errors in radial and spiral MRI data using only the data necessary to acquire the images. No extra data is required and no special scan must be done to perform the corrections using this unique method.


• Radial scans have been employed in order to take advantage of undersampling for increased speed of imaging
• Gradient delays and eddy currents can cause differences between specified and acquired k-space trajectories, causing errors and leading to image degradation. Gradient inhomogeneity problems are exacerbated in radial scans
• Current scanners use readout profile alternation to correct for gradient delays in radial and spiral data
• Correction for gradient delays is not possible with new golden angle (a spatial sampling method) scans or when chemical shift effects (dislocation of protons by Fourier transformation when converting from frequency to spatial domain) are important
• Traditionally, data is acquired in a special way and these errors are inferred, but that requirement cannot be met for all scans.

Technology Description

The novel MR pulse sequence and analysis method of this invention eliminates the need to compensate for traditional errors. In this novel method, undersampled data from a radial or spiral scan is fitted to an analytic function to infer the peak of the data along the direction parallel to the readout. The difference between this peak point and the point at which the center of k-space was supposed to have been collected in an important quantity. The method then solves for the 3-axis gradient delays that lead to the measured gradient shifts, and adds the derived delays to each coordinate to produce a clean image.


• Method can be integrated into MR scanner acquisition sequence with no noticeable increase in time
• Correction of gradient delay errors in MRI data when other methods are unavailable or impractical
• Ability to correct gradient delay errors using acquired data itself
• Eliminates need for extra data collection or special scanning or calibration to perform corrections

Intellectual Property Status

A U.S. Provisional Patent Application has been filed

Figure 1. Uncorrected phantom images (above) and phantom images corrected with the proposed invention (below)

David Smith
Licensing manager: 
Chris Harris

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