Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
Magnetic Resonance Research Center, Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands.
Magn Reson Med. 2022 Mar;87(3):1165-1173. doi: 10.1002/mrm.29053. Epub 2021 Oct 17.
Deuterium metabolic imaging could potentially be used to investigate metabolism in skeletal muscle noninvasively. However, skeletal muscle is a tissue with a high degree of spatial organization. In this study, we investigated the effect of incomplete motional averaging on the naturally abundant deuterated water signal in 7 Tesla deuterium spectra of the lower leg muscles and the dependence on the angle between the muscle fibers and the main magnetic field B , as determined by DTI.
Natural abundance deuterium MRSI measurements of the right lower leg muscles were performed at 7 Tesla. Three subjects were scanned in a supine position, with the right leg parallel with the B field. One subject was scanned twice; during the second scan, the subject was laying on his right side and the right knee was bent such that the angle between the right lower leg and B was approximately 45°. DTI was performed in the same subjects in the same positions at 3 Tesla to determine muscle fiber angles.
We observed splittings in the natural abundance deuterated water signal. The size of the splittings varied between different muscles in the lower leg but were mostly similar among subjects for each muscle. The splittings depended on the orientation of the muscle fibers with respect to the main magnetic field B .
Partial molecular alignment in skeletal muscle leads to residual deuteron quadrupolar couplings in deuterated water, the size of which depends on the angle between the muscle fibers and B .
氘代谢成像是一种潜在的用于研究骨骼肌代谢的非侵入性方法。然而，骨骼肌是一种具有高度空间组织的组织。在这项研究中，我们研究了不完全运动平均对 7T 下小腿肌肉天然丰度氘水信号的影响，以及这种影响与扩散张量成像（DTI）确定的肌纤维与主磁场 B 之间角度的关系。
在 7T 下对右小腿肌肉进行天然丰度氘磁共振波谱成像（MRSI）测量。3 名受试者均以仰卧位进行扫描，右腿与 B 场平行。其中 1 名受试者进行了两次扫描；第二次扫描时，受试者侧卧，右膝弯曲，使小腿与 B 的夹角约为 45°。在同一位置，对同一受试者使用 3T 进行 DTI 以确定肌纤维角度。
我们观察到天然丰度氘水信号的分裂。小腿不同肌肉之间的分裂大小不同，但对于每个肌肉，受试者之间的分裂大小大多相似。分裂取决于肌纤维相对于主磁场 B 的方向。
骨骼肌中的部分分子排列导致氘水中残余的氘核四极耦合，其大小取决于肌纤维与 B 之间的角度。
