Meeting Banner
Abstract #4421

On the spatiotemporal phase modulation of odd and even EPI echoes at 300 mT/m diffusion MRI: A field monitoring analysis

Gabriel Ramos Llorden1, Daniel Park1, Hong-Hsi Lee1, Alina Scholz2, Boris Keil2, Lawrence L. Wald1,3, Thomas L. Witzel4, and Susie Y. Huang1,3
1Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 2Institute of Medical Physics and Radiation Protection, Mittelhessen University of Applied Sciences, Giessen, Germany, 3Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States, 4Q Bio Inc, San Carlos, CA, United States

Synopsis

Keywords: Gradients, BrainMost of EPI ghosting algorithms assume that odd/even of phase modulations, either of first or higher spatial order, are stationary through the readout. Hence, a phase maps (or a linear function) for the subset of odd and even k-space lines is judged enough to model Nyquist ghosting and obtaining ghosting free images. Nevertheless, we demonstrate with field monitoring that for high-gradient strength diffusion MRI, persistent eddy currents from the diffusion module interfere non-linearly with the image encoding, leading to phase modulations that are time-varying during the readout. Implications for existing ghosting correction algorithms and potential alternatives are discussed.

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.

Keywords