使用多梯度回波序列在0.55 T场强下进行髓鞘水成像。
Myelin water imaging at 0.55 T using a multigradient-echo sequence.
作者信息
Schäper Jessica, Bieri Oliver
机构信息
Department of Biomedical Engineering, University of Basel, Basel, Switzerland.
Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, Switzerland.
出版信息
Magn Reson Med. 2024 Mar;91(3):1043-1056. doi: 10.1002/mrm.29949. Epub 2023 Nov 27.
PURPOSE
To investigate the prospects of a multigradient-echo (mGRE) acquisition for in vivo myelin water imaging at 0.55 T.
METHODS
Scans were performed on the brain of four healthy volunteers at 0.55 and 3 T, using a 3D mGRE sequence. The myelin water fraction (MWF) was calculated for both field strengths using a nonnegative least squares (NNLS) algorithm, implemented in the qMRLab suite. The quality of these maps as well as single-voxel fits were compared visually for 0.55 and 3 T.
RESULTS
The obtained MWF values at 0.55 T are consistent with previously reported ones at higher field strengths. The MWF maps are a considerable improvement over the ones at 3 T. Example fits show that 0.55 T data is better described by an exponential model than 3 T data, making the assumed multi-exponential model of the NNLS algorithm more accurate.
CONCLUSION
This first assessment shows that mGRE myelin water imaging at 0.55 T is feasible and has the potential to yield better results than at higher fields.
目的
研究在0.55 T场强下采用多梯度回波（mGRE）采集技术进行体内髓鞘水成像的前景。
方法
使用三维mGRE序列，对4名健康志愿者的大脑分别在0.55 T和3 T场强下进行扫描。利用qMRLab软件包中实现的非负最小二乘法（NNLS）算法计算两种场强下的髓鞘水分数（MWF）。对0.55 T和3 T场强下这些图谱的质量以及单像素拟合结果进行视觉比较。
结果
在0.55 T场强下获得的MWF值与之前在更高场强下报道的值一致。与3 T场强下的图谱相比，0.55 T场强下的MWF图谱有显著改善。示例拟合结果表明，指数模型对0.55 T数据的描述比3 T数据更好，这使得NNLS算法所假定的多指数模型更为准确。
结论
首次评估表明，在0.55 T场强下进行mGRE髓鞘水成像可行，并且有可能比在更高场强下获得更好的结果。
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