Abstract
PurposeTo compare signal‐to‐noise ratio (SNR) efficiency and diffusion tensor metrics of cardiac diffusion tensor mapping using acceleration‐compensated spin‐echo (SE) and stimulated echo acquisition mode (STEAM) imaging.MethodsDiffusion weighted SE and STEAM sequences were implemented on a clinical 1.5 Tesla MR system. The SNR efficiency of SE and STEAM was measured (b = 50–450 s/mm2) in isotropic agar, anisotropic diffusion phantoms and the in vivo human heart. Diffusion tensor analysis was performed on mean diffusivity, fractional anisotropy, helix and transverse angles.ResultsIn the isotropic phantom, the ratio of SNR efficiency for SE versus STEAM, SNRt(SE/STEAM), was 2.84 ± 0.08 for all tested b‐values. In the anisotropic diffusion phantom the ratio decreased from 2.75 ± 0.05 to 2.20 ± 0.13 with increasing b‐value, similar to the in vivo decrease from 2.91 ± 0.43 to 2.30 ± 0.30. Diffusion tensor analysis revealed reduced deviation of helix angles from a linear transmural model and reduced transverse angle standard deviation for SE compared with STEAM. Mean diffusivity and fractional anisotropy were measured to be statistically different (P < 0.001) between SE and STEAM.ConclusionCardiac DTI using motion‐compensated SE yields a 2.3–2.9× increase in SNR efficiency relative to STEAM and improved accuracy of tensor metrics. The SE method hence presents an attractive alternative to STEAM based approaches. Magn Reson Med 76:862–872, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Highlights
The fiber architecture of the heart has significant influence on cardiac function, mechanical contraction and electrophysiology [1,2,3,4,5]
Cardiac diffusion tensor imaging using motion-compensated SE yields up to 2.9Â increase in signal-to-noise ratio (SNR) efficiency relative to Because the SE approach requires only one cardiac cycle to acquire a diffusion weighted image, the sequence is suited for free-breathing navigator gated acquisition
diffusion tensor imaging (DTI) acquisition was performed during free-breathing with a navigator gating scheme as proposed by NiellesVallespin et al [18] along three (b 1⁄4 100 s/mm2) and nine (b 1⁄4 450 s/mm2) diffusion directions without visual feedback system
Summary
The fiber architecture of the heart has significant influence on cardiac function, mechanical contraction and electrophysiology [1,2,3,4,5]. The principal orientation of myofibers can be obtained from histological studies [6,7,8] or ex vivo [9,10,11] and in vivo [12,13,14,15,16,17,18,19,20,21,22,23,24] diffusion tensor imaging (DTI). While histological exams provide localized information on myocyte orientation with very high spatial resolution ex vivo, cardiac DTI allows assessment of myofiber aggregates noninvasively and in vivo. Fiber disarray and myocardial remodeling due to myocardial infarction and cardiomyopathies have been assessed by DTI methods both in animal and humans subjects [28,29,30,31,32,33]. Whereas mean diffusivity increased in myocardial infarction, FA was found to decrease
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
