Abstract #2933

Improving Temporal Resolution in fMRS: Assessing Reduced Phase Cycling in semi-LASER MRS

Alex Ensworth^1,2, John L.K. Kramer^2,3,4, Erin L. MacMillan^4,5,6, and Cornelia Laule^1,2,4,5,6,7

¹Physics and Astronomy, The University of British Columbia, Vancouver, BC, Canada, ²International Collaboration on Repair Discoveries (ICORD), The University of British Columbia, Vancouver, BC, Canada, ³Department of Anesthesiology, Pharmacology and Therapeutics, The University of British Columbia, Vancouver, BC, Canada, ⁴Djavad Mowafaghian Center for Brain Health (DMBCH), The University of British Columbia, Vancouver, BC, Canada, ⁵Radiology, The University of British Columbia, Vancouver, BC, Canada, ⁶UBC MRI Research Centre, The University of British Columbia, Vancouver, BC, Canada, ⁷Pathology and Laboratory Medicine, The University of British Columbia, Vancouver, BC, Canada

Synopsis

Keywords: Spectroscopy, Spectroscopy, fMRS, Phase Cycling, semi-LASER, FSL MRS, brain, ghost, artifacts

Motivation: Phase cycling is important for removal of ghosts but limits temporal resolution of functional MRS (fMRS).

Goal(s): To investigate the effects of reducing phase cycle steps in semi-LASER fMRS to enhance temporal resolution while maintaining data integrity.

Approach: Static ¹H-MRS on healthy volunteers using semi-LASER with varying amounts of phase cycle steps. Spectra were fit with FSL-MRS to extract glutamate peak areas and CRLBs.

Results: Cycling only the phase of the excitation pulse resulted in Glu peak areas within 17% of the default 32-step acquisition and similarly low CRLBs. Temporal resolution in fMRS could be improved by only phase cycling the excitation pulse.

Impact: This study demonstrates the impact of reducing phase cycles in MRS and provides guidance on how to reduce phase cycles to enhance temporal resolution and improve the feasibility of fMRS in clinical and research settings.

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