Motion and eddy current–induced signal dephasing in in vivo cardiac DTI. Issue 1 (23rd December 2019)

• Record Type: Journal Article
• Authors: Stoeck, Christian T.; von Deuster, Constantin; van Gorkum, Robbert J. H.; Kozerke, Sebastian
• Is Part Of: Magnetic resonance in medicine. Volume 84:Issue 1(2020)
• Page Start: 277
• Page End: 288
• Publication Date: 2019-12-23
• Subjects: cardiac DTI -- in vivo -- second‐order motion‐compensated DTI -- STEAM -- tensor Imaging; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.28132
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : 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.