Extracting more for less: multi-echo MP2RAGE for simultaneous T1-weighted imaging, T1 mapping, R2∗ mapping, SWI, and QSM from a single acquisition

Hongfu Sun, Jon O. Cleary, Rebecca Glarin, Scott C. Kolbe, Roger J. Ordidge, Bradford A. Moffat, G. Bruce Pike

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Abstract

Purpose: To demonstrate simultaneous T1-weighted imaging, T1 mapping, R2 * mapping, SWI, and QSM from a single multi-echo (ME) MP2RAGE acquisition. Methods: A single-echo (SE) MP2RAGE sequence at 7 tesla was extended to ME with 4 bipolar gradient echo readouts. T1-weighted images and T1 maps calculated from individual echoes were combined using sum of squares and averaged, respectively. ME-combined SWI and associated minimum intensity projection images were generated with TE-adjusted homodyne filters. A QSM reconstruction pipeline was used, including a novel phase-offsets estimation from multi-echoes (POEM) method to properly combine the phase images from the 32 receiver channels. Measurements of susceptibility, R2 *, and T1 of brain tissue from ME-MP2RAGE were compared with those from standard ME-gradient echo and SE-MP2RAGE. Results: The ME combined T1-weighted, T1 map, SWI, and minimum intensity projection images showed increased SNRs compared to the SE results. The proposed POEM coil combination method led to QSM results free of phase-singularity artifacts, which were present in the standard adaptive combination method. T1-weighted, T1, and susceptibility maps from ME-MP2RAGE were comparable to those obtained from SE-MP2RAGE and ME-gradient echo, whereas R2 * maps showed increased blurring and reduced SNR. T1, R2 *, and susceptibility values of brain tissue from ME-MP2RAGE were consistent with those from SE-MP2RAGE and ME-gradient echo. Conclusion: High-resolution structural T1 weighted imaging, T1 mapping, R2 * mapping, SWI, and QSM can be extracted from a single 8.5-min ME-MP2RAGE acquisition using a customized reconstruction pipeline. This method can be applied to replace separate SE-MP2RAGE and ME-gradient echo acquisitions to significantly shorten total scan time.

Original languageEnglish
Pages (from-to)1178-1191
Number of pages14
JournalMagnetic Resonance in Medicine
Volume83
Issue number4
DOIs
Publication statusPublished - Apr 2020

Keywords

  • coil combination
  • magnetic susceptibility
  • ME-MP2RAGE
  • multiparametric mapping
  • POEM
  • QSM

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