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Motion and eddy current–induced signal dephasing in in vivo cardiac DTI
Author(s) -
Stoeck Christian T.,
Deuster Constantin,
Gorkum Robbert J. H.,
Kozerke Sebastian
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28132
Subject(s) - dephasing , diffusion mri , systole , fractional anisotropy , imaging phantom , nuclear magnetic resonance , physics , cardiac cycle , eddy current , dither , cardiac imaging , signal (programming language) , diastole , biomedical engineering , materials science , computer science , optics , magnetic resonance imaging , computer vision , medicine , radiology , condensed matter physics , cardiology , quantum mechanics , programming language , noise shaping , blood pressure
Purpose To address motion in cardiac DWI, stimulated‐echo acquisition mode (STEAM) and second‐order motion‐compensated spin‐echo (SE) sequences have been proposed. Despite applying motion‐compensation strategies, residual motion can cause misleading signal attenuation. The purpose of this study is to estimate the motion‐induced error in both sequences by analysis of image phase. Methods Diffusion‐weighted motion‐compensated SE sequences and STEAM imaging was applied in vivo with diffusion encoding along 3 orthogonal directions. A b ‐value range of 100 to 600 s/mm 2 and trigger delays of 25%, 50%, and 75% of end systole and middiastole were used. Eddy‐current contributions were obtained from phantom measurements. After computation of motion‐induced phase maps, the amount of signal dephasing was computed from phase gradients, and the resulting errors in diffusion tensor parameters were calculated. Results Motion‐induced dephasing from the STEAM sequence showed less dependency on the b ‐value and no dependency on the heart phase, whereas SE imaging performed best at 75% end systole followed by 50% end systole and middiastole. For a typical experimental setting, errors of 3.3%/3.0% mean diffusivity, 4.9%/4.8% fractional anisotropy, 2.9º/3.2º helix angulation, 0.8º/0.7º transverse angulation, and 9.9º/10.0º sheet angulation (SE/STEAM) were calculated. Conclusion Image phase contains valuable information regarding uncompensated motion and eddy currents in cardiac DTI. Although the trigger delay window for SE is narrower compared with the STEAM‐based approach, imaging in both systole and diastole is feasible and both sequences perform similarly if the trigger delays are selected carefully with SE.