Landheer Karl, Gajdošík Martin, Treacy Michael, Juchem Christoph
Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, New York, USA.
Radiology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
Magn Reson Med. 2020 Nov;84(5):2327-2337. doi: 10.1002/mrm.28282. Epub 2020 May 19.
We aimed to investigate the concentration and effective T relaxation time of macromolecules assessed with an ultra-short TE sLASER sequence in 2 brain regions, the occipital and frontal cortex, in both genders at 3T.
An optimized sLASER sequence was used in conjunction with a double-inversion preparation module to null the metabolites. Eight equally spaced TEs were chosen from 20.1 to 62.1 ms, and the macromolecules were modeled by 10 line broadened singlets. The amplitude of each of the macromolecule signals was extracted at each TE and fit to a monoexponential function to extract the respective effective T values. Absolute quantification of the macromolecule resonances was performed using water signal as a reference. A total of 10 young healthy adult subjects (5 females) were scanned, with spectra being obtained from both the frontal and occipital cortex. Differences in the effective T relaxation times and concentrations were investigated between both regions and genders.
A wide disparity was observed between the effective T values of the individual resonances; however, no significant differences between gender or region for any of the measured macromolecule concentration or effective T values were found.
The effective T relaxation times and concentration of 10 different macromolecule resonances were measured and found to be well represented by the monoexponential model. These results will be useful for absolute quantification of macromolecules in future studies, or in the generation of synthetic basis sets for optimization or machine learning.
我们旨在研究在3T场强下，使用超短回波时间的sLASER序列评估枕叶和额叶皮质这两个脑区中大分子的浓度及有效T弛豫时间，涉及男女两性。
使用优化的sLASER序列结合双反转准备模块以消除代谢物信号。从20.1至62.1毫秒中选择8个等间距的回波时间，大分子由10个线宽展宽的单峰模拟。在每个回波时间提取每个大分子信号的幅度，并拟合为单指数函数以提取各自的有效T值。以水信号为参考对大分子共振进行绝对定量。共扫描了10名年轻健康的成年受试者（5名女性），获取了额叶和枕叶皮质的光谱。研究了两个脑区和不同性别之间有效T弛豫时间和浓度的差异。
观察到各个共振的有效T值之间存在很大差异；然而，在所测量的任何大分子浓度或有效T值方面，未发现性别或脑区之间存在显著差异。
测量了10种不同大分子共振的有效T弛豫时间和浓度，发现单指数模型能很好地描述这些结果。这些结果将有助于未来研究中大分子的绝对定量，或用于生成用于优化或机器学习的合成基集。
