Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Aix Marseille Université, CNRS, CRMBM-CEMEREM, UMR 7339, Marseille, France.
Magn Reson Med. 2017 Oct;78(4):1362-1372. doi: 10.1002/mrm.26523. Epub 2016 Nov 17.
This paper describes a technique that can be used in vivo to measure the dipolar relaxation time, T , of macromolecular protons contributing to magnetization transfer (MT) in tissues and to produce quantitative T maps.
The technique builds upon the inhomogeneous MT (ihMT) technique that is particularly sensitive to tissue components with long T . A standard ihMT experiment was altered to introduce a variable time for switching between positive and negative offset frequencies for RF saturation. A model for the dependence of ihMT was developed and used to fit data acquired in vivo.
Application of the method to images from brains of healthy volunteers produced values of T = (5.9 ± 1.2) ms in gray matter and T = (6.2 ± 0.4) ms in white matter regions and provided maps of the T parameter.
The model and experiments described provide access to a new relaxation characteristic of tissue with potentially unique diagnostic information. Magn Reson Med 78:1362-1372, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
本文描述了一种可在体测量对磁化转移（MT）有贡献的大分子质子的偶极弛豫时间 T 的技术，并生成定量 T 图。
该技术基于对 T 较长的组织成分特别敏感的不均匀 MT（ihMT）技术。对标准 ihMT 实验进行了修改，引入了在正、负偏移频率之间切换的可变时间以进行 RF 饱和。建立了 ihMT 的依赖模型，并用于拟合体内采集的数据。
将该方法应用于健康志愿者大脑的图像中，在灰质中得到 T = (5.9 ± 1.2) ms，在白质中得到 T = (6.2 ± 0.4) ms，并提供了 T 参数图。
本文描述的模型和实验提供了一种新的组织弛豫特性，具有潜在的独特诊断信息。磁共振医学 78:1362-1372, 2017。© 2016 国际磁共振学会。
