Abstract #3933

A dynamic shim approach to correct eddy-currents and concomitant-field using multi-coil AC/DC shim array

Congyu Liao^1,2, Jason Stockmann³, Xiaozhi Cao^1,2, Adam Kerr^2,4, and Kawin Setsompop^1,2

¹Department of Radiology, Stanford University, Stanford, CA, United States, ²Department of Electrical Engineering, Stanford University, Stanford, CA, United States, ³Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, ⁴Stanford Center for Cognitive and Neurobiological Imaging, Stanford University, Stanford, CA, United States

Synopsis

Keywords: System Imperfections, Diffusion/other diffusion imaging techniques

Motivation: To correct undesirable eddy-current and concomitant-fields effect in MRI acquisitions.

Goal(s): To achieve successful eddy-current and concomitant-fields mitigations, paving the way for high-quality 3D-invivo diffusion MRI with high-SNR.

Approach: We developed a dynamic shim approach with a multi-coil AC/DC shim-array to correct eddy-currents induced-phase in diffusion-prep encoding, and concomitant-field in long spiral in double-oblique positions.

Results: Invivo experiments were performed on the AC/DC shim-array to demonstrate cardiac-gated, multi-shot 3D-diffusion-prepared DTI acquisition without need for SNR-zapping stabilizer. High-quality, high-b-value(2000 s/mm²) acquisition was achieved where a synergistic combination of shim-array and pre-pulse gradient mitigation strategies were employed to minimize eddy-current phase in this difficult case.

Impact: We proposed a dynamic shim approach for robust invivo eddy-current correction in 3D-DTI with short preparation-time and high-SNR. Our results demonstrates the AC/DC coil's effectiveness in compensating challenging concomitant-fields during double-oblique slice acquisitions, especially with long-spiral sampling and high-performance gradients.

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.