Abstract #4287

Gradient Unwarping: Reverse Engineering the Warpfield with Spherical Harmonics

Paul Polak^1,2, David Lindner¹, Jannis Hanspach¹, Michael Dwyer¹, Niels Bergsland¹, Nicola Bertolino^1,2, Robert Zivadinov^1,2, and Ferdinand Schweser^1,2

¹Neurology, Buffalo Neuroimaging Analysis Center, State University of New York at Buffalo, Buffalo, NY, United States, ²Molecular and Translational Imaging, Clinical Translational Research Center, Buffalo, NY, United States

Gradient “unwarping” is the removal of image distortions caused by non-linearity of the imaging gradient fields. Exasperated by increasing distance from isocenter, the unwarping process is applied to every image by the manufacturer and generally is a “black-box” process occurring near the end of the image processing pipeline. This is problematic for researchers who source their data from a more primitive step, e.g. from raw k-space, since this data is generally “warped”. Presented here is a method to reverse engineer the spherical harmonic coefficients that describe the warp field and are used by the vendor’s black-box process, allowing the researcher to perform the gradient unwarping off-line as a post-processing step.

How to access this content:

For one year after publication, abstracts and videos are only open to registrants of this annual meeting. Registrants should use their existing login information. Non-registrant access can be purchased via the ISMRM E-Library.

After one year, current ISMRM & ISMRT members get free access to both the abstracts and videos. Non-members and non-registrants must purchase access via the ISMRM E-Library.

After two years, the meeting proceedings (abstracts) are opened to the public and require no login information. Videos remain behind password for access by members, registrants and E-Library customers.

Click here for more information on becoming a member.