Higher-Order Motion-Compensation for In Vivo Cardiac Diffusion Tensor Imaging in Rats

Abstract

Motion of the heart has complicated in vivo applications of cardiac diffusion MRI and diffusion tensor imaging (DTI), especially in small animals such as rats where ultra-high-performance gradient sets are currently not available. Even with velocity compensation via, for example, bipolar encoding pulses, the variable shot-to-shot residual motion-induced spin phase can still give rise to pronounced artifacts. This study presents diffusion-encoding schemes that are designed to compensate for higher-order motion components, including acceleration and jerk, which also have the desirable practical features of minimal TEs and high achievable b-values. The effectiveness of these schemes was verified numerically on a realistic beating heart phantom, and demonstrated empirically with in vivo cardiac diffusion MRI in rats. Compensation for acceleration, and lower motion components, was found to be both necessary and sufficient for obtaining diffusion-weighted images of acceptable quality and SNR, which yielded the first in vivo cardiac DTI demonstrated in the rat. These findings suggest that compensation for higher order motion, particularly acceleration, can be an effective alternative solution to high-performance gradient hardware for improving in vivo cardiac DTI.

Novel insights into in‐vivo diffusion tensor cardiovascular magnetic resonance using computational modelling and a histology‐based virtual microstructure

“…1 While historically the DTI literature has focussed on the brain, 2 recent developments in diffusion tensor cardiovascular magnetic resonance (DT-CMR) have overcome the difficulties associated with measuring diffusion in the dynamic environment of the heart. [3][4][5][6][7][8] This has facilitated in-vivo assessment of microstructural abnormalities in a number of patient cohorts. [9][10][11][12] The nature of a beating heart means that traditional Stejskal-Tanner-type diffusion-weighted spin echo techniques cannot be used.…”

Spin echo versus stimulated echo diffusion tensor imaging of the in vivo human heart

“…With recent improvements in gradient hardware becoming widely available on clinical MR systems and dedicated diffusion gradient designs, diffusion weighted single-shot spinecho (SE) sequences have become feasible for in vivo cardiac DTI. Several studies have shown that signal attenuation due to myocardial motion can be addressed successfully by incorporating motion compensated diffusion gradient waveforms (17,19,(35)(36)(37)(38)(40)(41)(42)(43). Promising results of the in vivo human (38) and rat (42) heart using second and third order motion compensated DTI have been presented recently.…”

Diffusion tensor imaging and histology of developing hearts

“…DTI has emerged as a preferred technique for noninvasive quantifications of myocardial structures. Although the feasibility of in vivo cardiac DTI has long been demonstrated , recent advances in both gradient hardware and imaging technologies have made in vivo cardiac DTI more widely used . The principal direction of diffusion anisotropy (i.e.…”