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Abstract #3962

Parallel 2D-RF Excitation for Arbitrarily Shaped Regionof-Interest MR Spectroscopy at 16.4 T

Dinesh K. Deelchand1, Xiaoping Wu1, Pierre-Gilles Henry1, Pierre-Francois Van de Moortele1

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

In this study we demonstrate with phantom experiments the feasibility of selectively exciting arbitrary shaped voxel using 2D-RF pulse design (segmented radial k-space trajectory) with parallel RF excitation at 16.4 T while achieving sufficient excitation bandwidth for 1H MR spectroscopy. A novel simulation guided segment-wise RF pulse design is introduced to tackle the issue of gradient imperfection and is shown to preserve the excitation quality in the presence of gradient waveform deviations.

Keywords

accuracy achieve achieving acquisition acquisitions actual adiabatic although arbitrarily arbitrary back bandwidth bore capability central channel channels chemical coil coils compute correct covering critical cubic delineates density design designed deviations domain done element errors even excitation excite expected feasibility field fields fixed form forth frequencies fully fundings furthermore general gradient greatly guided hand henry horizontal improving includes individual initially intensities intrinsic introduce issue larger latter limit limited location maps match maximize measured metabolites minimal minimize mode necessary novel obstacles offer offset optimal outside parallel pattern patterns periphery phantom placed power preliminary preserving proposed pulse pulses radial receive reduce reduced reducing refocusing regime require resources running satisfactory segment segmented segments select selective selectively shape shaped shim shorten side simulated simulation simulations simulator slew slice space spatial spectral spectroscopy spectrum spin split spoilers spoke spokes structures substantially sufficient system taking target though together trajectories trajectory transmit travels typically vanish water waveform whole window